Pathology recall practice
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Q1. A 75-year-old woman sustains an osteoporotic vertebral compression fracture after a minor fall. Which serum finding is most typical of primary osteoporosis?
Appeared in (recall papers): September 2016; April 2017; January 2020; April 2021; May 2022; 2022 or 2023 (session not specified); Paper/session not recorded in source
A. Hypercalcaemia
B. Normocalcaemia
C. Hypocalcaemia
D. Hyperphosphataemia
Answer and explanation
B. Normocalcaemia
Primary osteoporosis reduces bone mass without usually disrupting serum calcium homeostasis. Serum calcium, phosphate and ALP are usually normal; abnormal values prompt assessment for secondary bone disease.
A. Hypercalcaemia suggests another process such as primary hyperparathyroidism or malignancy, not uncomplicated primary osteoporosis.
C. Low calcium suggests vitamin D deficiency, hypoparathyroidism or another secondary metabolic problem.
D. Raised phosphate is not characteristic of uncomplicated osteoporosis and warrants evaluation of renal or endocrine disorders.
- A fragility fracture after low-energy trauma may establish clinical osteoporosis.
- DEXA T-score ≤ −2.5 at relevant sites supports osteoporosis in postmenopausal women and men aged ≥50 years.
- Normal serum calcium does not exclude severe osteoporosis.
Q2. A patient with urinary schistosomiasis has chronic bladder irritation. Which epithelial adaptation is classically associated with this infection?
Appeared in (recall papers): January 2018; 2021 (session not specified)
A. Columnar dysplasia with goblet cells
B. Transitional-cell neoplasia
C. Granulomatous metaplasia
D. Squamous metaplasia of urothelium
Answer and explanation
D. Squamous metaplasia of urothelium
Chronic Schistosoma haematobium infection irritates the bladder urothelium and is associated with squamous metaplasia. Long-standing disease increases the risk of squamous-cell carcinoma of the bladder.
A. Goblet-cell intestinal metaplasia is not the classic schistosomiasis-associated adaptation.
B. Neoplasia is autonomous new growth, which may be benign or malignant; it is not the specific adaptive cell-type response asked here.
C. Schistosomiasis can cause granulomatous inflammation, but granulomas are not a type of epithelial metaplasia.
- S. haematobium deposits eggs in the urinary tract.
- Haematuria is a classic presenting feature.
- Squamous metaplasia is an adaptation; dysplasia and squamous carcinoma are distinct later events.
Q3. Which type of epithelium normally lines the urinary bladder?
Appeared in (recall papers): September 2017; September 2020; September 2021
A. Transitional epithelium (urothelium)
B. Non-keratinising stratified squamous epithelium
C. Columnar epithelium with goblet cells
D. Keratinising stratified squamous epithelium
Answer and explanation
A. Transitional epithelium (urothelium)
The urinary bladder is lined by specialised stratified transitional epithelium (urothelium). Its umbrella cells and changing configuration permit distension while limiting exposure of deeper tissues to urine.
B. Non-keratinising squamous epithelium lines portions of other urogenital structures, but not the normal bladder body.
C. Goblet-cell columnar epithelium suggests intestinal differentiation or metaplasia rather than normal bladder lining.
D. Keratinising squamous epithelium is not the normal urinary bladder lining.
- Umbrella cells form the superficial urothelial layer.
- Urothelium also lines the renal pelvis and ureters.
- Chronic irritation can induce squamous metaplasia.
Q4. Which coagulation factor is specific to the initiation of the tissue-factor (extrinsic) pathway?
Appeared in (recall papers): September 2016; January 2019; January 2020; January 2021; May 2022; September 2022; January 2023; January 2024
A. Factor I (fibrinogen)
B. Factor IX
C. Factor VII
D. Factor X
Answer and explanation
C. Factor VII
Tissue factor exposed after vascular injury binds factor VII/VIIa and initiates the extrinsic pathway. The common pathway follows activation of factor X.
A. Fibrinogen is converted to fibrin in the common terminal pathway.
B. Factor IX is part of the intrinsic pathway, classically affected in haemophilia B.
D. Factor X participates in the common pathway, activated via both intrinsic and extrinsic mechanisms.
- PT/INR is used to assess the extrinsic and common pathways.
- aPTT assesses intrinsic and common pathways.
- Factor VII has the shortest half-life among vitamin K-dependent clotting factors.
Q5. In a postoperative wound infection, which process coats bacteria to enhance their subsequent ingestion by phagocytes?
Appeared in (recall papers): January 2016; September 2017; Paper/session not recorded in source
A. Apoptosis
B. Opsonisation
C. Autophagy
D. Phagocytosis
Answer and explanation
B. Opsonisation
Opsonisation coats microbial surfaces with molecules such as IgG and complement C3b, facilitating recognition and ingestion by phagocytes. Phagocytosis is the engulfment step that follows; it is not synonymous with opsonisation.
A. Apoptosis is programmed cellular death and does not describe coating microbes for uptake.
C. Autophagy is intracellular degradation and recycling of cellular components.
D. Phagocytosis is the actual engulfment of bacteria, rather than the preparatory enhancement through coating.
- Major opsonins include IgG and C3b.
- Neutrophils and macrophages use Fc and complement receptors.
- Opsonisation and phagocytosis are related but distinct processes.
Q6. A patient with long-standing Hashimoto thyroiditis develops a primary thyroid lymphoma. From which lineage does the lymphoma usually arise?
Appeared in (recall papers): January 2017
A. B lymphocytes
B. T lymphocytes
C. Macrophages
D. Plasma cells
Answer and explanation
A. B lymphocytes
Primary thyroid lymphomas associated with Hashimoto thyroiditis are most commonly B-cell non-Hodgkin lymphomas, including diffuse large B-cell and extranodal marginal zone (MALT) lymphoma. Chronic lymphocytic inflammation increases lymphoma risk.
B. T-cell thyroid lymphoma is uncommon and not the usual Hashimoto-associated type.
C. Macrophages do not give rise to the common primary thyroid B-cell lymphomas.
D. A plasma-cell neoplasm is not the classic lymphoma lineage in this setting.
- Rapidly enlarging thyroid mass in Hashimoto disease warrants lymphoma evaluation.
- MALT lymphoma arises in acquired mucosa-associated lymphoid tissue.
- Thyroid lymphoma must be distinguished from anaplastic thyroid carcinoma.
Q7. A 5-year-old child has disproportionate short stature suggestive of achondroplasia. What is its inheritance pattern?
Appeared in (recall papers): January 2016; April 2017
A. X-linked recessive
B. Y-linked
C. Autosomal recessive
D. Autosomal dominant
Answer and explanation
D. Autosomal dominant
Achondroplasia is caused by an activating FGFR3 variant and follows autosomal dominant inheritance. Many affected children have a de novo variant despite unaffected parents.
A. FGFR3-associated achondroplasia is not an X-linked recessive disorder.
B. Y-linked inheritance cannot explain affected females and is not involved in achondroplasia.
C. The condition is not typically autosomal recessive; a single pathogenic FGFR3 allele is sufficient.
- FGFR3 is located on chromosome 4p16.3.
- Achondroplasia impairs endochondral ossification.
- Foramen magnum stenosis and cervicomedullary compression are important complications.
Q8. Which serum tumour marker is characteristically elevated in testicular yolk sac tumours?
Appeared in (recall papers): September 2022; April 2025
A. β-hCG
B. LDH
C. Alpha-fetoprotein (AFP)
D. S100
Answer and explanation
C. Alpha-fetoprotein (AFP)
Yolk sac tumours (endodermal sinus tumours) often produce alpha-fetoprotein. AFP is useful for diagnosis, staging and monitoring response in nonseminomatous germ-cell tumours.
A. β-hCG is associated especially with trophoblastic differentiation and choriocarcinoma.
B. LDH is a nonspecific marker of tumour burden and lacks yolk sac specificity.
D. S100 is a marker used in melanocytic and some neural-origin tumours, not a typical serum marker of yolk sac tumours.
- Schiller–Duval bodies are characteristic histological structures.
- Pure seminoma does not produce AFP.
- Post-orchidectomy AFP kinetics help assess residual disease.
Q9. An asbestos-exposed construction worker has diffuse pleural thickening and a pleural mass. What is the most likely malignancy?
Appeared in (recall papers): May 2024
A. Pulmonary adenocarcinoma
B. Malignant pleural mesothelioma
C. Squamous-cell carcinoma of the lung
D. Small-cell carcinoma of the lung
Answer and explanation
B. Malignant pleural mesothelioma
Malignant pleural mesothelioma arises from pleural mesothelial cells and has a strong association with asbestos exposure. Pleural thickening or an encasing pleural mass is a classic pattern.
A. Lung adenocarcinoma is a pulmonary epithelial tumour, not the characteristic diffuse pleural malignancy.
C. Squamous-cell lung cancer more often arises centrally in major bronchi, although variable appearances occur.
D. Small-cell lung cancer is usually a central neuroendocrine lung malignancy and is strongly associated with smoking.
- Mesothelioma may present decades after occupational exposure.
- The pleura is a major site; peritoneal mesothelioma also occurs.
- Histological subtypes include epithelioid, sarcomatoid and biphasic.
Q10. A 68-year-old lifelong non-smoker has a peripheral lung mass. Which primary lung carcinoma is most likely?
Appeared in (recall papers): January 2018; January 2019
A. Adenocarcinoma
B. Small-cell carcinoma
C. Squamous-cell carcinoma
D. Large-cell carcinoma
Answer and explanation
A. Adenocarcinoma
Pulmonary adenocarcinoma is the most common lung cancer histology among never-smokers and often occurs peripherally. Definitive diagnosis still requires imaging and histology; this is a probability-based single-best-answer question.
B. Small-cell carcinoma is more strongly related to smoking and typically centrally located.
C. Squamous-cell carcinoma also has a strong smoking association and often arises centrally.
D. Large-cell carcinoma is an uncommon diagnosis of exclusion after modern pathological classification.
- Histology, not location alone, establishes cancer subtype.
- TTF-1 and napsin A commonly support lung adenocarcinoma in appropriate settings.
- Molecular testing can guide targeted therapy in metastatic disease.
Q11. A man previously treated by total colectomy for familial adenomatous polyposis develops progressive painless obstructive jaundice. Which extracolonic malignancy is particularly associated with FAP?
Appeared in (recall papers): April 2017; Paper/session not recorded in source
A. Gastric adenocarcinoma
B. Hepatocellular carcinoma
C. Primary biliary cholangitis
D. Duodenal/periampullary adenocarcinoma
Answer and explanation
D. Duodenal/periampullary adenocarcinoma
Familial adenomatous polyposis is associated with duodenal and periampullary adenomas and carcinoma even after colectomy. An ampullary lesion can cause obstructive jaundice.
A. Gastric neoplasia can occur in polyposis syndromes but does not best explain the classic FAP-related periampullary risk in this case.
B. Hepatocellular carcinoma is not the characteristic postcolectomy malignancy risk in FAP.
C. Primary biliary cholangitis is an autoimmune cholestatic disease, not a malignancy associated with FAP.
- FAP is caused by germline APC variants.
- Colectomy does not eliminate extracolonic malignancy risk.
- Duodenal surveillance includes visualisation of the ampulla.
Q12. A thyroid biopsy shows dense mature lymphocytic infiltration with oncocytic Hürthle-cell change. Which diagnosis is most likely?
Appeared in (recall papers): 2022 or 2023 (session not specified); January 2023; May 2023; April 2026
A. Graves disease
B. Hashimoto thyroiditis
C. Papillary thyroid carcinoma
D. Medullary thyroid carcinoma
Answer and explanation
B. Hashimoto thyroiditis
Hashimoto thyroiditis is a chronic autoimmune lymphocytic thyroiditis. Histology may show lymphoid follicles, germinal centres and oxyphilic (Hürthle) cell change.
A. Graves disease classically exhibits diffuse hyperplasia and scalloped colloid in the setting of stimulating TSH-receptor antibodies.
C. Papillary thyroid carcinoma is identified by characteristic nuclear features; a papillary architecture is not required in every variant.
D. Medullary thyroid carcinoma is derived from parafollicular C cells and associated with calcitonin/amyloid.
- Anti-TPO antibodies are common in Hashimoto thyroiditis.
- Hürthle cells have abundant eosinophilic granular cytoplasm.
- Hashimoto thyroiditis commonly causes primary hypothyroidism.
Q13. A persistent unilateral eczematous nipple lesion contains malignant glandular cells in the epidermis. Which underlying process is particularly associated with this finding?
Appeared in (recall papers): January 2025
A. Ductal carcinoma in situ or invasive breast carcinoma
B. Physiological lactational change
C. Fat necrosis alone
D. Simple fibroadenoma
Answer and explanation
A. Ductal carcinoma in situ or invasive breast carcinoma
Mammary Paget disease is commonly associated with an underlying ductal breast malignancy. Persistent unilateral nipple eczema warrants assessment.
B. Lactation does not produce malignant epidermal cells.
C. Fat necrosis produces damaged adipocytes and inflammation, not Paget cells.
D. A fibroadenoma does not explain malignant intraepidermal glandular cells.
- Persistent unilateral nipple eczema warrants assessment.
- Paget cells are malignant glandular cells; the underlying lesion may be in situ or invasive.
- Paget disease of the nipple commonly affects the nipple and may extend to the areola.
Q14. Which microscopic change directly weakens medial elastic support in an aorta predisposed to dissection?
Appeared in (recall papers): September 2024; January 2025; April 2025; April 2026
A. Intimal fatty streak formation alone
B. Degeneration of medial elastic tissue
C. Intimal smooth-muscle hyperplasia alone
D. Adventitial scar formation alone
Answer and explanation
B. Degeneration of medial elastic tissue
Fragmentation and loss of medial elastic lamellae reduce the supporting framework of the aortic wall. Separate the initiating intimal tear from the weakened media.
A. A fatty streak is an intimal lipid lesion rather than loss of medial elastic lamellae.
C. This thickens the intima and is different from degeneration of medial elastic support.
D. An adventitial scar is outside the media and does not describe the specified medial change.
- Separate the initiating intimal tear from the weakened media.
- Medial degeneration alone does not establish a diagnosis of Marfan syndrome.
- A dissection creates a false channel within the aortic wall.
Q15. A saccular aneurysm is found at a cerebral arterial branch point. Which structural abnormality predisposes to this lesion?
Appeared in (recall papers): April 2018; April 2021
A. Septic destruction of an artery as the usual mechanism
B. Atherosclerotic plaque rupture as the defining lesion
C. Focal weakness of the media and internal elastic lamina
D. Tearing of bridging veins
Answer and explanation
C. Focal weakness of the media and internal elastic lamina
Reduced support at cerebral arterial branch points favours saccular outpouching. Rupture may cause subarachnoid haemorrhage.
A. Infective aneurysms are a different subgroup, not the usual branch-point saccular lesion.
B. Plaque rupture is a thrombotic atherosclerotic event, not the defining structural lesion of a typical saccular aneurysm.
D. Bridging-vein injury causes subdural bleeding rather than an arterial aneurysm.
- Rupture may cause subarachnoid haemorrhage.
- Aneurysm formation is multifactorial; avoid describing every lesion as purely congenital.
- Branch points in the circle of Willis are typical locations for saccular aneurysms.
Q16. A woman develops severe abdominal pain, tachycardia, hypertension and motor weakness after starting a potentially porphyrinogenic medicine. Abdominal imaging shows no surgical cause. Which diagnosis best unifies these findings?
Appeared in (recall papers): April 2019; April 2021; Paper/session not recorded in source
A. Primary biliary cholangitis
B. Uncomplicated gallbladder stones
C. Acute intermittent porphyria
D. Gilbert syndrome
Answer and explanation
C. Acute intermittent porphyria
A neurovisceral attack can combine abdominal pain, autonomic disturbance and neuropathy. During an attack, urinary porphobilinogen is an important initial test.
A. PBC typically produces chronic cholestasis and pruritus.
B. Gallstones do not account for a motor neuropathy and autonomic syndrome.
D. Gilbert syndrome causes mild unconjugated hyperbilirubinaemia without this neurovisceral syndrome.
- During an attack, urinary porphobilinogen is an important initial test.
- Normal imaging does not exclude an acute hepatic porphyria.
- Acute porphyria may be associated with hyponatraemia.
Q17. A well adult has recurrent mild jaundice during fasting or intercurrent illness. Bilirubin is predominantly unconjugated; liver enzymes and haemolysis investigations are normal. What is the most likely diagnosis?
Appeared in (recall papers): January 2021
A. Gilbert syndrome
B. Extrahepatic biliary obstruction
C. Autoimmune haemolysis
D. Acute viral hepatitis
Answer and explanation
A. Gilbert syndrome
Reduced bilirubin conjugation produces intermittent isolated unconjugated hyperbilirubinaemia. Unconjugated bilirubin is albumin-bound and is not excreted in urine.
B. Obstruction predominantly raises conjugated bilirubin and often cholestatic enzymes.
C. Haemolysis would be supported by anaemia, reticulocytosis and other haemolytic markers.
D. Hepatitis usually produces hepatocellular enzyme abnormalities.
- Unconjugated bilirubin is albumin-bound and is not excreted in urine.
- Dark bilirubin-positive urine should prompt another explanation.
- Gilbert syndrome involves reduced UGT1A1-mediated bilirubin conjugation.
Q18. A woman has chronic pruritus, a cholestatic liver enzyme pattern and positive antimitochondrial antibodies. Which diagnosis is most likely?
Appeared in (recall papers): January 2018; April 2021; September 2021; Paper/session not recorded in source
A. Primary biliary cholangitis
B. Gilbert syndrome
C. Primary sclerosing cholangitis
D. Autoimmune hepatitis
Answer and explanation
A. Primary biliary cholangitis
Cholestatic enzymes and antimitochondrial antibodies support autoimmune small intrahepatic bile duct disease. ALP is often disproportionately raised.
B. Gilbert syndrome causes isolated unconjugated hyperbilirubinaemia rather than cholestatic injury.
C. PSC is characterised by fibrosing biliary strictures and does not have the same characteristic AMA association.
D. Autoimmune hepatitis usually has a more hepatocellular pattern and different diagnostic antibody and histological features.
- ALP is often disproportionately raised.
- The modern name is primary biliary cholangitis; cirrhosis is not required at diagnosis.
- PBC primarily injures small intrahepatic bile ducts.
Q19. Four weeks after kidney transplantation, biopsy shows interstitial lymphocytic inflammation and tubulitis. Which immune mechanism best explains this acute cellular rejection?
Appeared in (recall papers): Paper/session not recorded in source
A. Recipient T-cell-mediated injury
B. Preformed antibody injury within minutes of reperfusion
C. IgE-mediated mast-cell degranulation
D. Passive deposition of inhaled particles
Answer and explanation
A. Recipient T-cell-mediated injury
Tubulitis and interstitial inflammation support acute T-cell-mediated rejection. Timing alone cannot distinguish T-cell-mediated from antibody-mediated acute rejection.
B. This is the classic hyperacute pattern, with vascular injury and thrombosis.
C. This produces immediate allergic reactions, not typical rejection tubulitis.
D. This is unrelated to kidney allograft rejection.
- Timing alone cannot distinguish T-cell-mediated from antibody-mediated acute rejection.
- Use biopsy findings and the antibody assessment to classify rejection.
- Tubulitis describes inflammatory cells infiltrating tubular epithelium.
Q20. A patient has cold intolerance, constipation, bradycardia and raised TSH with low free T4. Which lipid abnormality commonly accompanies this endocrine disorder?
Appeared in (recall papers): May 2024
A. Markedly reduced LDL as the usual pattern
B. Raised LDL cholesterol
C. Raised HDL as the sole defining abnormality
D. Chylomicronaemia as an obligatory finding
Answer and explanation
B. Raised LDL cholesterol
Hypothyroidism can reduce LDL clearance and cause secondary hypercholesterolaemia. Check for hypothyroidism when investigating secondary dyslipidaemia.
A. Reduced LDL is not the characteristic untreated hypothyroid association.
C. An isolated HDL rise does not describe the characteristic secondary dyslipidaemia.
D. Severe chylomicronaemia is not an obligatory consequence of hypothyroidism.
- Check for hypothyroidism when investigating secondary dyslipidaemia.
- Interpret TSH with free T4 and the clinical context.
- Primary hypothyroidism usually produces high TSH with low free T4.
Q21. A thyroid carcinoma has nuclear grooves and intranuclear cytoplasmic inclusions, with cervical lymph node deposits. Which subtype is most likely?
Appeared in (recall papers): May 2024
A. Papillary thyroid carcinoma
B. Follicular thyroid carcinoma
C. Anaplastic thyroid carcinoma
D. Medullary thyroid carcinoma
Answer and explanation
A. Papillary thyroid carcinoma
The characteristic nuclear changes and propensity for lymphatic spread support papillary carcinoma. Papillary carcinoma can present with cervical lymphadenopathy.
B. Follicular carcinoma requires capsular or vascular invasion and more often spreads haematogenously.
C. Anaplastic carcinoma is a highly undifferentiated aggressive tumour.
D. Medullary carcinoma arises from C cells and may contain amyloid.
- Papillary carcinoma can present with cervical lymphadenopathy.
- Nuclear features matter more than a purely papillary architecture.
- Papillary carcinoma is the commonest thyroid carcinoma.
Q22. A patient with a pituitary macroadenoma develops sudden severe headache, visual loss, ophthalmoplegia and hypotension. MRI shows haemorrhage into the lesion. What is the diagnosis?
Appeared in (recall papers): January 2026
A. Chronic primary hypothyroidism alone
B. Stable non-functioning microadenoma
C. Pituitary apoplexy
D. Uncomplicated migraine
Answer and explanation
C. Pituitary apoplexy
Acute haemorrhage or infarction of a pituitary lesion can cause visual, neurological and endocrine compromise. Acute cortisol deficiency can be life-threatening.
A. This does not explain the abrupt haemorrhagic sellar syndrome.
B. A stable small lesion does not account for the acute syndrome.
D. Migraine does not explain haemorrhage into a pituitary mass and adrenal compromise.
- Acute cortisol deficiency can be life-threatening.
- Visual symptoms reflect proximity to the optic pathways and cavernous sinus.
- Ophthalmoplegia may reflect cavernous sinus involvement near the pituitary.
Q23. Which combination of endocrine lesions is characteristic of MEN1?
Appeared in (recall papers): May 2024
A. Parathyroid, pituitary and pancreatic neuroendocrine tumours
B. Medullary thyroid carcinoma and phaeochromocytoma
C. Retinoblastoma and osteosarcoma
D. Renal carcinoma and retinal haemangioblastoma
Answer and explanation
A. Parathyroid, pituitary and pancreatic neuroendocrine tumours
These constitute the classic MEN1 endocrine pattern. MEN1 is an autosomal dominant tumour predisposition syndrome.
B. This is associated with MEN2 rather than the classic MEN1 triad.
C. This suggests an RB1-related tumour predisposition.
D. This suggests von Hippel–Lindau disease.
- MEN1 is an autosomal dominant tumour predisposition syndrome.
- Primary hyperparathyroidism is a common manifestation.
- MEN1 is associated with pathogenic variants in the MEN1 tumour suppressor gene.
Q24. Which prematurely activated pancreatic enzyme can initiate activation of other digestive zymogens during acute pancreatitis?
Appeared in (recall papers): January 2025
A. Elastase
B. Lipase
C. Trypsin
D. Amylase
Answer and explanation
C. Trypsin
Premature intrapancreatic trypsin activation can activate other digestive zymogens. Trypsinogen is normally activated in the intestinal lumen.
A. Elastase degrades elastic tissue after activation; it is not the initiating zymogen activator in this question.
B. Lipase digests triglycerides and is not the principal activator of pancreatic protease zymogens.
D. Amylase digests carbohydrate and does not initiate the protease zymogen cascade.
- Trypsinogen is normally activated in the intestinal lumen.
- Do not confuse a diagnostic serum marker with the initiating intracellular mechanism.
- Trypsin is normally secreted as the inactive precursor trypsinogen.
Q25. A Meckel diverticulum contains lobules of basophilic acinar cells arranged around small ducts. What tissue is present?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Brunner glands
B. Thyroid tissue
C. Exocrine pancreatic tissue
D. Gastric foveolar epithelium
Answer and explanation
C. Exocrine pancreatic tissue
Basophilic acinar cells and ducts form the characteristic exocrine pancreatic architecture. Meckel diverticula may contain ectopic gastric or pancreatic tissue.
A. Brunner glands are pale mucous glands in duodenal submucosa, not the specified basophilic acinar lobules.
B. Thyroid tissue forms colloid-containing follicles rather than exocrine acini and ducts.
D. Foveolar cells are mucus-secreting surface cells rather than lobules of pancreatic acini and ducts.
- Meckel diverticula may contain ectopic gastric or pancreatic tissue.
- Endocrine pancreatic islets are structurally distinct from exocrine acini.
- Gastric heterotopia can cause ulceration and bleeding from a Meckel diverticulum.
Q26. A patient has mucocutaneous pigmentation around the lips and hamartomatous gastrointestinal polyps. Which syndrome is most likely?
Appeared in (recall papers): January 2025
A. Peutz–Jeghers syndrome
B. MEN1
C. Lynch syndrome
D. Familial adenomatous polyposis
Answer and explanation
A. Peutz–Jeghers syndrome
The combination of characteristic pigmentation and hamartomatous polyps supports this diagnosis. STK11 is the major associated tumour suppressor gene.
B. MEN1 chiefly affects endocrine glands.
C. Lynch syndrome is a mismatch-repair cancer predisposition without this characteristic polyp-pigmentation combination.
D. FAP is characterised by numerous adenomatous polyps.
- STK11 is the major associated tumour suppressor gene.
- Hamartomatous histology does not remove the syndrome-associated cancer risk.
- Peutz–Jeghers polyps commonly involve the small intestine.
Q27. A newborn has intestinal obstruction from inspissated meconium. Subsequent assessment identifies pancreatic insufficiency and an elevated sweat chloride concentration. What underlying disease is most likely?
Appeared in (recall papers): April 2017; January 2021; January 2025
A. Hirschsprung disease
B. Cystic fibrosis
C. Isolated meconium plug syndrome
D. Congenital hypothyroidism
Answer and explanation
B. Cystic fibrosis
CFTR dysfunction can cause meconium ileus, pancreatic insufficiency and an elevated sweat chloride concentration. Meconium ileus is different from an isolated meconium plug.
A. Aganglionosis causes distal functional obstruction but does not account for pancreatic insufficiency and the sweat test.
C. This does not explain persistent multisystem CF features.
D. Hypothyroidism can cause bowel hypomotility but does not produce this pancreatic and sweat-chloride pattern.
- Meconium ileus is different from an isolated meconium plug.
- Malabsorption and recurrent respiratory disease provide later clues.
- CFTR dysfunction alters epithelial chloride and bicarbonate transport.
Q28. After antibiotics, a patient develops diarrhoea and colonic plaques composed of fibrin, mucus, inflammatory cells and necrotic debris. Which diagnosis best fits?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Crohn disease
B. Uncomplicated diverticulosis
C. Clostridioides difficile-associated pseudomembranous colitis
D. Ulcerative colitis
Answer and explanation
C. Clostridioides difficile-associated pseudomembranous colitis
Antibiotic-associated diarrhoea with pseudomembranous exudate strongly suggests C. difficile infection. Not every case of C. difficile infection has visible pseudomembranes.
A. Crohn disease more typically produces patchy transmural inflammation and may cause granulomas.
B. Diverticula alone do not explain diffuse inflammatory pseudomembranes.
D. UC can cause severe mucosal inflammation but is not the characteristic antibiotic-associated pseudomembranous diagnosis.
- Not every case of C. difficile infection has visible pseudomembranes.
- Diagnosis requires the clinical setting and appropriate stool testing.
- Toxins from C. difficile contribute to mucosal injury.
Q29. Severe intracranial injury is followed by upper gastrointestinal bleeding from acute gastric ulceration. Which named stress ulcer is classically associated with this setting?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Cushing ulcer
B. Rodent ulcer
C. Marjolin ulcer
D. Curling ulcer
Answer and explanation
A. Cushing ulcer
Cushing ulcers are associated with intracranial disease and injury. Vagal stimulation and acid hypersecretion contribute to the classical association.
B. This term describes an ulcerating basal cell carcinoma.
C. A Marjolin ulcer is malignant change in a chronic wound or scar.
D. Curling ulcers are classically associated with severe burns.
- Vagal stimulation and acid hypersecretion contribute to the classical association.
- Critically ill patients may also have stress-related mucosal ischaemia.
- Acute stress ulcers are different from chronic H. pylori-associated peptic ulcers.
Q30. An adult has an infiltrating cerebral tumour with necrosis, microvascular proliferation and extension across the corpus callosum. Which diagnosis is most likely?
Appeared in (recall papers): January 2018; Paper/session not recorded in source
A. Primary CNS lymphoma
B. Oligodendroglioma
C. Meningioma
D. Glioblastoma
Answer and explanation
D. Glioblastoma
An infiltrating astrocytic malignancy with necrosis and microvascular proliferation can cross the corpus callosum. A butterfly configuration is suggestive rather than individually diagnostic.
A. CNS lymphoma can also cross the corpus callosum, but the specified necrotic microvascular proliferative glial pattern favours glioblastoma.
B. This has a different integrated molecular diagnosis and classic morphology rather than the specified glioblastoma pattern.
C. Meningiomas are typically extra-axial dural-based tumours.
- A butterfly configuration is suggestive rather than individually diagnostic.
- Current classification also requires appropriate molecular assessment.
- Glioblastoma is an infiltrative tumour and may extend beyond the contrast-enhancing margin.
Q31. Surveillance biopsies in longstanding extensive ulcerative colitis show epithelial atypia and disordered maturation without invasion. Which finding is the principal premalignant change?
Appeared in (recall papers): January 2019; January 2020; Paper/session not recorded in source
A. Neutrophils alone
B. Epithelial dysplasia
C. Mucus accumulation alone
D. Simple oedema
Answer and explanation
B. Epithelial dysplasia
Dysplasia is the relevant neoplastic precursor assessed in colitis surveillance. Inflammatory atypia can complicate histological assessment.
A. Active inflammation is not synonymous with dysplasia.
C. Mucus without epithelial atypia does not establish dysplasia.
D. Oedema alone does not establish a neoplastic precursor.
- Inflammatory atypia can complicate histological assessment.
- Interpret dysplasia grade and distribution with specialist pathology review.
- Longstanding extensive colitis carries a higher colorectal neoplasia risk than isolated proctitis.
Q32. Histology of a painful interdigital nerve lesion in the forefoot shows thickening around the nerve. Which process best characterises Morton neuroma?
Appeared in (recall papers): January 2018; January 2019; January 2020; January 2021
A. Caseating granulomatous infection
B. Perineural fibrosis
C. Osteoid production by malignant cells
D. Malignant nerve sheath tumour
Answer and explanation
B. Perineural fibrosis
Morton neuroma is an entrapment neuropathy with perineural fibrosis, despite its name. The common name does not imply a true nerve tumour.
A. Caseating granulomas are not the defining finding.
C. This defines osteosarcoma, not an interdigital nerve lesion.
D. The usual lesion is not a malignant neoplasm.
- The common name does not imply a true nerve tumour.
- Forefoot pain may radiate into adjacent toes.
- The third interdigital space is a common site of Morton neuroma.
Q33. Which invasive malignancy is classically associated with Barrett oesophagus?
Appeared in (recall papers): April 2018; April 2019; April 2021; September 2024
A. Adenocarcinoma
B. Small-cell carcinoma
C. Basal cell carcinoma
D. Osteosarcoma
Answer and explanation
A. Adenocarcinoma
Barrett-associated intestinal metaplasia can progress through dysplasia to adenocarcinoma. Most people with Barrett oesophagus do not develop cancer.
B. This is not the characteristic Barrett-associated tumour.
C. This is predominantly a cutaneous malignancy.
D. This is a malignant bone-forming tumour.
- Most people with Barrett oesophagus do not develop cancer.
- Dysplasia grade changes the level of risk and follow-up.
- Barrett oesophagus is associated with chronic gastro-oesophageal reflux.
Q34. A smoker has recurrent painful inflammation beneath the areola. Squamous metaplasia and keratin plugging affect major lactiferous ducts. Which process best explains this pattern?
Appeared in (recall papers): January 2020; May 2022; May 2023; Paper/session not recorded in source
A. Periductal mastitis with subareolar abscess formation
B. Paget disease
C. Simple fibroadenoma
D. Lactational secretory change alone
Answer and explanation
A. Periductal mastitis with subareolar abscess formation
Keratin obstruction and duct inflammation can lead to recurrent subareolar sepsis and fistulation. Smoking is an important association.
B. Paget disease involves malignant glandular cells within nipple epidermis.
C. This usually presents as a discrete benign mass rather than recurrent duct-centred inflammation.
D. The described keratin-plugging process is not normal lactation.
- Smoking is an important association.
- A persistently atypical or non-resolving breast lesion still requires assessment.
- Periductal inflammation can produce a mammary duct fistula.
Q35. A colorectal neoplasm extends into the muscularis mucosae but not through it into the submucosa. Which classification best describes its depth?
Appeared in (recall papers): January 2020
A. pT1 carcinoma
B. Intramucosal carcinoma, pTis
C. pT3 carcinoma
D. pT2 carcinoma
Answer and explanation
B. Intramucosal carcinoma, pTis
Colorectal carcinoma confined to the mucosa, including muscularis mucosae, is classified as Tis. Do not confuse muscularis mucosae with muscularis propria.
A. T1 requires invasion into the submucosa.
C. T3 extends through muscularis propria into pericolorectal tissue.
D. T2 requires invasion into the muscularis propria.
- Do not confuse muscularis mucosae with muscularis propria.
- Submucosal invasion is a clinically important threshold in a malignant polyp.
- Colorectal Tis should not be interpreted using staging rules for another organ.
Q36. Distal oesophageal squamous mucosa is replaced by columnar epithelium containing goblet cells. Which cellular process has occurred?
Appeared in (recall papers): September 2020; April 2021; September 2021; May 2022; September 2022; 2022 or 2023 (session not specified); January 2023; May 2023; April 2025; January 2026
A. Invasion
B. Hypertrophy
C. Hyperplasia alone
D. Metaplasia
Answer and explanation
D. Metaplasia
One differentiated epithelial phenotype has been replaced by another. The direction is squamous to intestinal-type columnar epithelium.
A. A change in epithelial type alone does not establish basement membrane breach.
B. Hypertrophy means an increase in cell size.
C. Hyperplasia means increased cell number without necessarily changing the epithelial type.
- The direction is squamous to intestinal-type columnar epithelium.
- Metaplasia and dysplasia are different processes.
- Goblet cells are mucus-producing intestinal epithelial cells.
Q37. Malignant glands from a colorectal adenoma extend through the muscularis mucosae into submucosa. What has developed?
Appeared in (recall papers): January 2021
A. Dysplasia confined to epithelium
B. Simple hyperplastic polyp
C. Intramucosal carcinoma only
D. Invasive adenocarcinoma, at least pT1
Answer and explanation
D. Invasive adenocarcinoma, at least pT1
Submucosal invasion establishes an invasive colorectal carcinoma. Assess margins, differentiation and lymphovascular invasion in a malignant polyp.
A. Dysplasia alone does not extend into the submucosa.
B. A hyperplastic polyp does not contain invasive malignant glands.
C. The lesion has crossed beyond the mucosa.
- Assess margins, differentiation and lymphovascular invasion in a malignant polyp.
- T1 is a depth category and does not by itself specify nodal status.
- Lymphovascular invasion adds risk beyond the presence of submucosal invasion alone.
Q38. Failure of normal programmed cell death in interdigital tissue may contribute to which developmental abnormality?
Appeared in (recall papers): January 2021
A. Marfan syndrome
B. Syndactyly
C. Hereditary spherocytosis
D. Achondroplasia
Answer and explanation
B. Syndactyly
Persistence of interdigital tissue can leave adjacent digits joined. Apoptosis is regulated cell death with limited inflammatory leakage.
A. Marfan syndrome is a connective tissue disorder, not failure of interdigital apoptosis.
C. This is a red-cell membrane disorder.
D. Achondroplasia is related to altered FGFR3 signalling and endochondral growth.
- Apoptosis is regulated cell death with limited inflammatory leakage.
- Necrosis and apoptosis have different morphological patterns.
- Apoptotic bodies are cleared by neighbouring cells and phagocytes.
Q39. Bronchial biopsy in a smoker shows replacement of ciliated columnar epithelium by mature stratified squamous epithelium without atypia. What is this process?
Appeared in (recall papers): January 2021; 2021 (session not specified)
A. Squamous metaplasia
B. Hypertrophy
C. Dysplasia
D. Invasive carcinoma
Answer and explanation
A. Squamous metaplasia
Chronic irritation can cause replacement by a different mature epithelial phenotype. Metaplasia may impair normal mucociliary function.
B. The defining change is epithelial type, not cell size.
C. The stem specifically excludes epithelial atypia.
D. There is no described malignant invasion.
- Metaplasia may impair normal mucociliary function.
- A sputum specimen containing squamous cells alone cannot establish bronchial metaplasia.
- Loss of cilia can impair clearance of inhaled particles.
Q40. A skin biopsy shows atypical squamous cells extending through the epithelial basement membrane into dermis. Which process is present?
Appeared in (recall papers): January 2021; Paper/session not recorded in source
A. Metaplasia alone
B. Hyperplasia alone
C. Carcinoma in situ
D. Invasive squamous cell carcinoma
Answer and explanation
D. Invasive squamous cell carcinoma
Malignant epithelial cells breaching the basement membrane establish invasion. Assess depth, differentiation and other risk features after confirming invasion.
A. A mature cell-type change does not account for invasive atypical cells.
B. Increased cell number without malignant invasion is insufficient.
C. In situ disease remains above the basement membrane.
- Assess depth, differentiation and other risk features after confirming invasion.
- Cytological atypia alone does not establish an invasive tumour.
- A tumour can show invasion even when the sampled surface component is small.
Q41. A patient with longstanding chronic kidney disease has enlargement of all four parathyroid glands due to increased numbers of chief cells. What is the cellular adaptation?
Appeared in (recall papers): April 2021
A. Metaplasia
B. Hypertrophy alone
C. Atrophy
D. Hyperplasia
Answer and explanation
D. Hyperplasia
An increase in cell number is hyperplasia. Secondary hyperparathyroidism commonly affects multiple glands.
A. There is no replacement by a different mature cell type.
B. Hypertrophy means an increase in individual cell size.
C. Atrophy is a reduction in tissue mass.
- Secondary hyperparathyroidism commonly affects multiple glands.
- Autonomous hypercalcaemia in advanced disease raises a separate question of tertiary hyperparathyroidism.
- Increased PTH secretion and increased chief-cell number describe function and morphology respectively.
Q42. An enlarged left ventricle contains cardiac myocytes of increased size without a corresponding increase in myocyte number. What is this adaptation?
Appeared in (recall papers): September 2021
A. Hyperplasia
B. Metaplasia
C. Dysplasia
D. Hypertrophy
Answer and explanation
D. Hypertrophy
Larger individual myocytes increase myocardial mass. Pressure overload can produce pathological hypertrophy.
A. This would require increased cell number.
B. The myocytes have not changed into another mature cell type.
C. Disordered atypical epithelial maturation is not described.
- Pressure overload can produce pathological hypertrophy.
- The microscopic finding alone does not identify the exact cause of ventricular enlargement.
- Hypertrophy can be a physiological or pathological response depending on the stimulus.
Q43. Which description best defines epithelial dysplasia?
Appeared in (recall papers): January 2021; May 2022; January 2023
A. Increase in otherwise normal cell number
B. Increase in individual cell size
C. Disordered maturation with cytological and architectural atypia
D. Replacement by another mature differentiated cell type
Answer and explanation
C. Disordered maturation with cytological and architectural atypia
Dysplasia describes abnormal epithelial maturation and organisation. Dysplasia is not synonymous with invasion.
A. This defines hyperplasia.
B. This defines hypertrophy.
D. This defines metaplasia.
- Dysplasia is not synonymous with invasion.
- Some dysplastic lesions regress; progression is not inevitable.
- Architectural disorder is assessed alongside nuclear atypia when grading dysplasia.
Q44. Mature lamellar bone develops within a previously fibrous soft-tissue scar. Which process best describes this change?
Appeared in (recall papers): May 2022; May 2023
A. Invasive carcinoma
B. Osseous metaplasia
C. Dysplasia
D. Atrophy
Answer and explanation
B. Osseous metaplasia
Bone has formed in a site previously occupied by a different mature tissue type. Metaplastic bone may occur after tissue injury.
A. Mature bone in a scar alone does not establish a malignant epithelial tumour.
C. Atypical epithelial maturation is not the described change.
D. Atrophy means tissue loss rather than formation of bone.
- Metaplastic bone may occur after tissue injury.
- Distinguish mature heterotopic bone from malignant osteoid.
- Heterotopic ossification describes bone forming outside the normal skeleton.
Q45. A patient with diabetes develops haematuria and passes sloughed renal tissue. Imaging shows loss of renal papillary tips. What is the most likely lesion?
Appeared in (recall papers): May 2022
A. Minimal change disease
B. Renal papillary necrosis
C. Simple renal cyst
D. IgA nephropathy alone
Answer and explanation
B. Renal papillary necrosis
Ischaemic necrosis of papillae can lead to haematuria and sloughing. Associations include diabetes, analgesic injury, obstruction and sickling disorders.
A. This causes nephrotic syndrome without papillary sloughing.
C. A simple cyst does not explain necrotic papillary tissue.
D. Glomerular bleeding does not produce characteristic loss of papillary tips.
- Associations include diabetes, analgesic injury, obstruction and sickling disorders.
- Sloughed papillae can obstruct the urinary tract.
- Renal papillae are the tips of the medullary pyramids.
Q46. A young adult has hundreds of histologically adenomatous colorectal polyps. Which inherited syndrome best fits?
Appeared in (recall papers): September 2022; January 2023; September 2024; April 2026
A. Peutz–Jeghers syndrome
B. Gilbert syndrome
C. Familial adenomatous polyposis
D. MEN1
Answer and explanation
C. Familial adenomatous polyposis
Numerous adenomas are characteristic of APC-associated FAP. Adenomas are neoplastic polyps with dysplasia.
A. This features hamartomatous polyps and mucocutaneous pigmentation.
B. This concerns bilirubin conjugation rather than colorectal polyposis.
D. This causes endocrine tumour predisposition.
- Adenomas are neoplastic polyps with dysplasia.
- Colectomy does not remove extracolonic cancer risks.
- FAP is usually inherited in an autosomal dominant manner.
Q47. An intravascular clot contains alternating pale platelet-fibrin layers and darker red-cell-rich layers. What does this layering indicate?
Appeared in (recall papers): September 2022
A. Formation in flowing blood before death
B. Caseating granulomatous inflammation
C. Amyloid deposition
D. Simple post-mortem sedimentation only
Answer and explanation
A. Formation in flowing blood before death
Lines of Zahn support an antemortem thrombus formed under flowing conditions. Distinguish a thrombus from a post-mortem clot.
B. Caseation has no platelet-fibrin lamination.
C. Amyloid is an extracellular protein deposit, not a layered thrombus.
D. Post-mortem clots lack the characteristic organised platelet-fibrin layering.
- Distinguish a thrombus from a post-mortem clot.
- The layering does not by itself date the thrombus precisely.
- Venous and arterial thrombi differ in composition and haemodynamic setting.
Q48. Years after an intra-articular fracture, a patient develops joint-space narrowing, subchondral sclerosis and osteophytes in that joint. What is the most likely diagnosis?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Secondary osteoarthritis
B. Osteosarcoma
C. Septic arthritis
D. Acute gout
Answer and explanation
A. Secondary osteoarthritis
Previous joint injury can accelerate degenerative cartilage loss. Intra-articular incongruity increases later osteoarthritis risk.
B. A malignant bone-forming tumour does not produce the typical degenerative joint constellation.
C. An acute infected joint requires a different clinical and microbiological pattern.
D. Gout causes episodic crystal-associated synovitis and does not alone explain this post-traumatic pattern.
- Intra-articular incongruity increases later osteoarthritis risk.
- Joint-space loss reflects articular cartilage loss.
- Osteophytes are marginal bony outgrowths characteristic of osteoarthritis.
Q49. A longstanding osteomyelitis sinus develops a new enlarging, indurated ulcer. Biopsy shows invasive malignant squamous cells. What complication has developed?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Squamous cell carcinoma arising in a chronic wound
B. Keloid alone
C. Uncomplicated granulation tissue
D. Basal cell carcinoma by definition
Answer and explanation
A. Squamous cell carcinoma arising in a chronic wound
Malignant transformation in a chronic scar or sinus is termed a Marjolin ulcer. A change in a chronic wound warrants biopsy.
B. A keloid does not contain invasive malignant squamous cells.
C. The biopsy establishes malignancy.
D. Marjolin ulcers are most commonly squamous carcinomas.
- A change in a chronic wound warrants biopsy.
- Do not assume every persistent sinus has undergone malignant transformation.
- Chronic burn scars and persistent ulcers are other settings for Marjolin carcinoma.
Q50. A benign breast cyst is lined by large cells with abundant eosinophilic cytoplasm and apical snouts, without atypia. What is the change?
Appeared in (recall papers): January 2023; Paper/session not recorded in source
A. Medullary thyroid carcinoma
B. Apocrine metaplasia
C. Invasive ductal carcinoma
D. Paget disease
Answer and explanation
B. Apocrine metaplasia
Benign cyst epithelium may show apocrine differentiation. Apocrine metaplasia alone is not a diagnosis of breast cancer.
A. This is a thyroid C-cell tumour.
C. The stem excludes atypia and invasion.
D. Paget cells are malignant cells within nipple epidermis.
- Apocrine metaplasia alone is not a diagnosis of breast cancer.
- Assess any accompanying atypia separately.
- The term metaplasia does not itself imply an invasive neoplasm.
Q51. Within minutes of reperfusion, a kidney graft becomes dusky. Biopsy shows widespread vascular thrombosis with antibody and complement deposition. Which mechanism is most likely?
Appeared in (recall papers): 2022 or 2023 (session not specified); January 2023; May 2023; January 2026
A. A newly generated T-cell response developing over weeks
B. Pre-existing recipient antibodies to donor antigens
C. IgE-mediated allergy to pollen
D. Chronic fibrotic remodelling over years
Answer and explanation
B. Pre-existing recipient antibodies to donor antigens
Preformed antibodies can activate complement and cause hyperacute vascular injury. Hyperacute rejection is distinct from a purely technical renal artery thrombosis.
A. This does not explain immediate antibody-positive vascular injury.
C. This is unrelated to donor antigen-specific graft thrombosis.
D. This does not occur within minutes.
- Hyperacute rejection is distinct from a purely technical renal artery thrombosis.
- Crossmatching reduces risk from pre-existing donor-reactive antibodies.
- Antibody-mediated endothelial injury can activate coagulation within a graft.
Q52. A patient with a clonal plasma-cell disorder develops systemic amyloid deposits. Which precursor is characteristic of AL amyloid?
Appeared in (recall papers): April 2021; January 2024; January 2025
A. Beta-2 microglobulin
B. Transthyretin
C. Immunoglobulin light chains
D. Serum amyloid A
Answer and explanation
C. Immunoglobulin light chains
Monoclonal light chains can misfold into AL amyloid fibrils. AL and AA refer to different precursor proteins.
A. This is associated with dialysis-related amyloid.
B. This causes ATTR amyloidosis rather than AL amyloid.
D. This is the precursor of AA amyloid associated with chronic inflammation.
- AL and AA refer to different precursor proteins.
- The underlying plasma-cell disorder requires assessment even when amyloid is the presenting problem.
- Light-chain deposition disease is distinct from fibrillar AL amyloidosis.
Q53. Skin is transferred from the thigh to a burn wound on the same patient. What type of graft is this?
Appeared in (recall papers): September 2016
A. Xenograft
B. Autograft
C. Isograft
D. Allograft
Answer and explanation
B. Autograft
Donor and recipient are the same person. Autografts avoid alloimmune rejection.
A. A xenograft crosses species.
C. An isograft is between genetically identical individuals.
D. An allograft is between genetically different people of the same species.
- Autografts avoid alloimmune rejection.
- Graft terminology depends on donor-recipient relationship, not anatomical distance.
- A split-thickness skin autograft includes epidermis and part of the dermis.
Q54. A heart valve is obtained from an unrelated deceased human donor. What is the donor-recipient graft category?
Appeared in (recall papers): September 2016; April 2021
A. Autograft
B. Isograft
C. Xenograft
D. Allograft
Answer and explanation
D. Allograft
The donor and recipient are genetically different members of the same species. A porcine valve is a xenograft.
A. The valve did not come from the recipient.
B. An unrelated donor is not genetically identical to the recipient.
C. Both donor and recipient are human.
- A porcine valve is a xenograft.
- Tissue processing and viability influence immune behaviour separately from the graft category.
- A genetically identical twin graft is an isograft.
Q55. Which material is demonstrated by Perls Prussian blue stain in tissue?
Appeared in (recall papers): April 2017; September 2018
A. Amyloid
B. Glycogen specifically
C. Neutral fat
D. Ferric iron in haemosiderin
Answer and explanation
D. Ferric iron in haemosiderin
Perls staining demonstrates ferric iron deposits. Iron-positive granules often represent haemosiderin.
A. Amyloid is classically demonstrated with Congo red.
B. Glycogen is assessed using PAS with diastase comparison.
C. Lipid requires appropriate fat stains and specimen handling.
- Iron-positive granules often represent haemosiderin.
- A special stain supports, rather than replaces, morphological interpretation.
- Haemosiderin can accumulate after haemorrhage as macrophages process iron.
Q56. Synovial fluid contains needle-shaped crystals with strong negative birefringence. What are they?
Appeared in (recall papers): September 2018
A. Cholesterol crystals
B. Calcium pyrophosphate
C. Calcium oxalate
D. Monosodium urate
Answer and explanation
D. Monosodium urate
Needle-shaped negatively birefringent crystals support gout. Crystals do not exclude coexisting joint infection.
A. These have a plate-like morphology rather than the characteristic urate needles.
B. CPP crystals are usually rhomboid and weakly positively birefringent.
C. These do not give the classic gout crystal pattern.
- Crystals do not exclude coexisting joint infection.
- Polarised microscopy assesses both shape and birefringence.
- CPPD can produce acute arthritis that clinically resembles gout.
Q57. A malnourished patient has impaired dark adaptation, conjunctival xerosis and Bitot spots. Which deficiency best explains the findings?
Appeared in (recall papers): September 2018; January 2020; January 2021; May 2022
A. Vitamin A
B. Vitamin B12
C. Vitamin K
D. Vitamin C
Answer and explanation
A. Vitamin A
Vitamin A deficiency affects vision and epithelial integrity. Night blindness may precede severe ocular surface damage.
B. B12 deficiency causes megaloblastic anaemia and neurological disease.
C. Vitamin K deficiency causes impaired coagulation.
D. Vitamin C deficiency causes scurvy, including bruising and impaired collagen formation.
- Night blindness may precede severe ocular surface damage.
- Corneal involvement can threaten sight.
- Vitamin A is fat-soluble, so malabsorption can contribute to deficiency.
Q58. An ovarian cyst contains mature skin, hair, cartilage and glandular tissue. Which diagnosis is most likely?
Appeared in (recall papers): April 2019; Paper/session not recorded in source
A. Pure yolk sac tumour
B. Mature cystic teratoma
C. Serous cystadenoma
D. Endometrioma
Answer and explanation
B. Mature cystic teratoma
A teratoma contains differentiated tissues from multiple germ layers. Mature tissue differs from an immature neuroepithelial component.
A. Yolk sac tumour is a malignant germ-cell tumour associated with AFP, not a mature dermoid pattern.
C. This does not explain the mixture of mature tissue types.
D. This contains endometriotic tissue and altered blood, not hair and cartilage.
- Mature tissue differs from an immature neuroepithelial component.
- Tumour markers are not substitutes for the tissue diagnosis.
- Malignant potential depends on site, age and teratoma subtype.
Q59. A patient with a very restricted diet has perifollicular bleeding, swollen gums and poor wound healing. Which deficiency best explains this pattern?
Appeared in (recall papers): September 2017; September 2019; September 2020; May 2022; 2022 or 2023 (session not specified); January 2023; September 2024
A. Vitamin B1
B. Vitamin B12
C. Vitamin A alone
D. Vitamin C
Answer and explanation
D. Vitamin C
Scurvy causes defective connective tissue support and impaired healing. Dietary history is central to recognising scurvy.
A. Thiamine deficiency causes beriberi and Wernicke-related disease.
B. B12 deficiency does not explain the characteristic perifollicular bleeding pattern.
C. Vitamin A deficiency classically impairs dark adaptation and epithelial integrity.
- Dietary history is central to recognising scurvy.
- Bleeding reflects fragile connective tissue, not necessarily abnormal coagulation tests.
- Humans require a dietary source of vitamin C.
Q60. A severely malnourished person with alcohol dependence develops peripheral neuropathy and high-output cardiac failure. Which deficiency is most likely?
Appeared in (recall papers): September 2020; September 2021
A. Vitamin K
B. Vitamin A
C. Vitamin C
D. Thiamine, vitamin B1
Answer and explanation
D. Thiamine, vitamin B1
Thiamine deficiency can cause neuropathy and wet beriberi with cardiac failure. Wet and dry beriberi emphasise cardiac and neurological manifestations.
A. Vitamin K deficiency impairs coagulation factor function.
B. Vitamin A deficiency chiefly affects vision and epithelial integrity.
C. Scurvy principally affects collagen-dependent tissues.
- Wet and dry beriberi emphasise cardiac and neurological manifestations.
- Suspected Wernicke encephalopathy requires urgent parenteral thiamine.
- Thiamine is needed for several carbohydrate-metabolism enzyme systems.
Q61. A patient with bilateral hilar lymphadenopathy has a biopsy showing well-formed non-necrotising granulomas. Infection and other causes are excluded. Which diagnosis is most likely?
Appeared in (recall papers): September 2020; January 2021; September 2021; May 2022; September 2024
A. Amyloidosis
B. Metastatic adenocarcinoma
C. Sarcoidosis
D. Simple reactive oedema
Answer and explanation
C. Sarcoidosis
Compatible clinical findings and non-necrotising granulomas support sarcoidosis after excluding alternatives. Non-necrotising granulomas are not specific for sarcoidosis.
A. Amyloid forms extracellular protein deposits rather than epithelioid granulomas.
B. This would show malignant epithelial glands or cells.
D. Oedema does not form organised granulomas.
- Non-necrotising granulomas are not specific for sarcoidosis.
- Clinical context and exclusion of infection remain essential.
- Granulomatous inflammation may be infectious or non-infectious.
Q62. A patient with rheumatoid arthritis has a firm subcutaneous elbow nodule. Histology shows central fibrinoid necrobiotic material surrounded by palisading histiocytes. What is the lesion?
Appeared in (recall papers): January 2018; September 2020; May 2022; September 2022; September 2024
A. Lipoma
B. Metastatic carcinoma
C. Gouty tophus by definition
D. Rheumatoid nodule
Answer and explanation
D. Rheumatoid nodule
This is the characteristic necrobiotic granulomatous pattern of a rheumatoid nodule. Do not describe all rheumatoid synovium as a rheumatoid nodule.
A. A lipoma contains mature adipose tissue.
B. Carcinoma would contain malignant epithelial cells.
C. Tophi contain urate crystal deposits with an associated inflammatory reaction.
- Do not describe all rheumatoid synovium as a rheumatoid nodule.
- Pannus is an inflamed proliferative synovial tissue process.
- Pressure areas are common locations for subcutaneous rheumatoid nodules.
Q63. An extracellular deposit stains with Congo red. Which appearance under polarised light supports amyloid?
Appeared in (recall papers): September 2020; September 2021
A. Strong negative birefringence of needles
B. Acid-fast red bacilli
C. Prussian blue granules
D. Apple-green birefringence
Answer and explanation
D. Apple-green birefringence
This is the classic optical feature of Congo-red-positive amyloid. Congo red demonstrates amyloid but does not identify its precursor protein.
A. This describes monosodium urate crystals.
B. These support mycobacterial organisms.
C. These indicate ferric iron.
- Congo red demonstrates amyloid but does not identify its precursor protein.
- Amyloid typing is needed to distinguish AL, AA, ATTR and other forms.
- Amyloid is an extracellular fibrillar protein deposit.
Q64. A biopsy contains invasive nests of atypical squamous cells with concentric keratin pearls and intercellular bridges. Which tumour is most likely?
Appeared in (recall papers): January 2023; January 2024
A. Basal cell carcinoma
B. Melanoma
C. Well-differentiated squamous cell carcinoma
D. Liposarcoma
Answer and explanation
C. Well-differentiated squamous cell carcinoma
Keratin production and squamous differentiation support SCC. Keratin pearls indicate squamous differentiation.
A. BCC typically has basaloid nests with peripheral palisading.
B. Melanoma arises from melanocytes and does not form keratin pearls.
D. This is a malignant adipocytic tumour.
- Keratin pearls indicate squamous differentiation.
- Invasion must be distinguished from an in situ squamous lesion.
- Intercellular bridges provide another clue to squamous differentiation.
Q65. A rapidly growing friable red skin nodule bleeds easily. Histology shows a lobular proliferation of capillary-sized vessels. What is the lesion?
Appeared in (recall papers): January 2023
A. Squamous carcinoma
B. Caseating granuloma
C. Keloid
D. Lobular capillary haemangioma
Answer and explanation
D. Lobular capillary haemangioma
This is the lesion commonly called pyogenic granuloma. The name is misleading: it is neither necessarily pyogenic nor a true granuloma.
A. The histology shows vascular lobules rather than malignant squamous invasion.
B. There is no described caseation or granulomatous infection.
C. A keloid is a collagenous scar.
- The name is misleading: it is neither necessarily pyogenic nor a true granuloma.
- Histology distinguishes it from malignant mimics.
- Despite its name, pyogenic granuloma does not require bacterial infection.
Q66. Prolonged systemic glucocorticoid treatment can impair wound strength principally through which effect?
Appeared in (recall papers): September 2024
A. Increased mature collagen deposition in every wound
B. Conversion of all collagen to keratin
C. Reduced fibroblast activity and collagen formation
D. Obligatory malignant transformation of wound edges
Answer and explanation
C. Reduced fibroblast activity and collagen formation
Glucocorticoids suppress inflammatory and reparative responses, including collagen synthesis. Healing depends on dose, duration, comorbidity and local conditions.
A. This is the opposite of the characteristic adverse effect.
B. Collagen and keratin are different structural proteins.
D. Steroids do not invariably cause malignant transformation.
- Healing depends on dose, duration, comorbidity and local conditions.
- Do not stop prescribed long-term steroids abruptly.
- Infection, hypoxia and malnutrition can impair healing alongside steroid exposure.
Q67. During leukocyte recruitment in an inflamed venule, which interaction mediates initial tethering and rolling?
Appeared in (recall papers): September 2024
A. Integrin-mediated firm adhesion only
B. Collagen synthesis by fibroblasts
C. Selectin-mediated transient adhesion
D. Passage through endothelial junctions
Answer and explanation
C. Selectin-mediated transient adhesion
Selectins support weak reversible interactions that permit rolling. Firm adhesion and rolling are distinct steps.
A. Integrin activation supports firm arrest after rolling.
B. This belongs to repair rather than initial leukocyte recruitment.
D. Transmigration follows adhesion.
- Firm adhesion and rolling are distinct steps.
- Chemokines activate leukocyte integrins before stable adhesion.
- Diapedesis means passage of leukocytes through the vessel wall.
Q68. Vitamin C deficiency impairs which step important for stable collagen formation?
Appeared in (recall papers): Paper/session not recorded in source
A. Production of calcitonin by C cells
B. Class switching from IgM to IgG
C. Hydroxylation of proline and lysine residues
D. Conversion of fibrinogen to fibrin
Answer and explanation
C. Hydroxylation of proline and lysine residues
Ascorbate supports the hydroxylase reactions required for normal collagen maturation. Defective collagen contributes to fragile capillaries and poor healing.
A. This is unrelated to collagen hydroxylation.
B. This is a B-cell immune process.
D. This is catalysed by thrombin.
- Defective collagen contributes to fragile capillaries and poor healing.
- Adequate protein and oxygen are also required for repair.
- Lysyl oxidase-mediated cross-linking is a different collagen maturation step from vitamin C-dependent hydroxylation.
Q69. Epithelioid cells and multinucleated giant cells in a granuloma arise chiefly from which cell lineage?
Appeared in (recall papers): April 2017; May 2023; January 2026; April 2026
A. Mature erythrocytes
B. Monocytes and macrophages
C. Platelets
D. Fibroblasts
Answer and explanation
B. Monocytes and macrophages
Activated macrophages form epithelioid histiocytes and can fuse into giant cells. Granuloma architecture includes activated macrophages with accompanying immune cells.
A. Red cells do not differentiate into histiocytes.
C. Platelets are anucleate megakaryocyte fragments.
D. Fibroblasts produce matrix and are not the source of these histiocytes.
- Granuloma architecture includes activated macrophages with accompanying immune cells.
- A granuloma is a reaction pattern, not a diagnosis by itself.
- Langhans-type giant-cell nuclear arrangement is not specific for tuberculosis.
Q70. A healing wound contains numerous newly formed capillaries, fibroblasts and loose extracellular matrix. Which process produces its vascular component?
Appeared in (recall papers): January 2018; January 2019; January 2020
A. Keratinisation alone
B. Haemostasis alone
C. Amyloid deposition
D. Angiogenesis
Answer and explanation
D. Angiogenesis
New vessels are a defining component of granulation tissue. Granulation tissue is prominent during the proliferative phase.
A. Keratin formation does not create the vascular bed.
B. An initial clot does not account for newly formed capillaries.
C. Amyloid is unrelated to normal granulation tissue vessel formation.
- Granulation tissue is prominent during the proliferative phase.
- Wound phases overlap; a day number alone does not identify one exclusive process.
- Fibroblasts lay down collagen and other extracellular matrix during repair.
Q71. A patient with recurrent perianal fistulae has patchy transmural intestinal inflammation and non-necrotising granulomas. Which diagnosis best fits?
Appeared in (recall papers): September 2020; January 2021; September 2021; May 2022; April 2025; Paper/session not recorded in source
A. Crohn disease
B. Ulcerative colitis
C. Simple diverticulosis
D. Irritable bowel syndrome
Answer and explanation
A. Crohn disease
Transmural inflammation and fistulation support Crohn disease. Granulomas may be absent in Crohn disease.
B. UC usually produces continuous mucosal disease; granulomas away from ruptured crypts and fistulation favour Crohn disease.
C. This does not explain the full inflammatory pattern.
D. IBS does not cause destructive granulomatous inflammation.
- Granulomas may be absent in Crohn disease.
- Fistulae reflect inflammation extending beyond the mucosa.
- Crohn disease can affect any part of the gastrointestinal tract.
Q72. Using the four-phase model of wound healing, which phase begins immediately to limit blood loss?
Appeared in (recall papers): January 2025; January 2026; April 2026
A. Haemostasis
B. Proliferation
C. Remodelling
D. Scar maturation only
Answer and explanation
A. Haemostasis
Vasoconstriction, platelet activity and coagulation establish an initial clot. The four phases are haemostasis, inflammation, proliferation and remodelling.
B. This later phase includes fibroblasts, angiogenesis and re-epithelialisation.
C. Remodelling alters collagen organisation and wound strength later.
D. Scar maturation does not provide immediate control of bleeding.
- The four phases are haemostasis, inflammation, proliferation and remodelling.
- They overlap rather than occurring as sharply separated time blocks.
- Early wound matrix is gradually replaced and reorganised during later remodelling.
Q73. A renal mass is associated with raised haemoglobin and an inappropriately high erythropoietin concentration. Which tumour is classically associated with this paraneoplastic pattern?
Appeared in (recall papers): January 2021; September 2024; Paper/session not recorded in source
A. Basal cell carcinoma
B. Papillary thyroid carcinoma
C. Gastric MALT lymphoma
D. Renal cell carcinoma
Answer and explanation
D. Renal cell carcinoma
RCC can produce erythropoietin and cause secondary erythrocytosis. Renal tumours may also present with haematuria.
A. BCC does not characteristically produce erythropoietin.
B. This is not the characteristic EPO-producing tumour in this setting.
C. This does not explain a solid renal mass with EPO excess.
- Renal tumours may also present with haematuria.
- Erythrocytosis has many causes; confirm the renal lesion rather than diagnosing RCC from haemoglobin alone.
- Paraneoplastic erythrocytosis is a secondary rather than clonal marrow cause of raised red-cell mass.
Q74. A man with prostate adenocarcinoma develops multiple sclerotic vertebral lesions. What pattern of bone metastasis is classically associated with this primary?
Appeared in (recall papers): January 2026
A. Purely benign bone islands in every case
B. Exclusively osteolytic metastases
C. Osteoblastic metastases
D. Osteoid osteoma
Answer and explanation
C. Osteoblastic metastases
Prostate cancer commonly produces sclerotic osteoblastic deposits. Metastatic bone disease can have mixed features.
A. New multiple lesions in this context require assessment for metastasis.
B. Prostate deposits are not classically exclusively lytic.
D. This is a different primary benign bone lesion.
- Metastatic bone disease can have mixed features.
- A new neurological deficit may indicate metastatic spinal cord compression.
- Osteoblastic activity produces increased bone density on radiographs.
Q75. A patient has recurrent Proteus urinary infection and a large branching renal calculus. Which composition is most characteristic?
Appeared in (recall papers): May 2024
A. Cholesterol
B. Cystine
C. Magnesium ammonium phosphate
D. Pure uric acid
Answer and explanation
C. Magnesium ammonium phosphate
Urease-producing infection promotes alkaline urine and struvite stone formation. Not every staghorn calculus is struvite.
A. Cholesterol is a gallstone constituent rather than a typical renal stone.
B. Cystine stones result from inherited cystinuria.
D. Uric acid stones are favoured by acidic urine.
- Not every staghorn calculus is struvite.
- Control of infection and complete stone assessment are important.
- Proteus produces urease, which promotes urinary alkalinisation.
Q76. A jaundiced patient has dark urine that tests positive for bilirubin. Which form of bilirubin accounts for this finding?
Appeared in (recall papers): September 2017; May 2022; May 2023; September 2024; April 2025; Paper/session not recorded in source
A. Albumin-bound unconjugated bilirubin
B. Stercobilin
C. Haemoglobin in all cases
D. Conjugated bilirubin
Answer and explanation
D. Conjugated bilirubin
Conjugated bilirubin is water-soluble and can enter urine. Reduced delivery of bile pigments to bowel can cause pale stools.
A. Unconjugated bilirubin is not normally filtered into urine.
B. Stercobilin gives stool its brown colour.
C. Bilirubinuria is different from haemoglobinuria.
- Reduced delivery of bile pigments to bowel can cause pale stools.
- Steatorrhoea in obstruction reflects reduced intestinal bile salts, a separate mechanism.
- Unconjugated and conjugated bilirubin behave differently because of water solubility and protein binding.
Q77. After major trauma, a patient develops diffuse wound oozing, platelets 34 × 10⁹/L, prolonged PT and aPTT, low fibrinogen and raised D-dimer. Which diagnosis best fits?
Appeared in (recall papers): April 2018; April 2019; April 2021; May 2022; 2022 or 2023 (session not specified); January 2023; April 2026; Paper/session not recorded in source
A. Aspirin effect alone
B. Isolated factor VIII deficiency
C. Disseminated intravascular coagulation
D. Immune thrombocytopenia alone
Answer and explanation
C. Disseminated intravascular coagulation
Systemic coagulation activation consumes platelets and factors, producing thrombosis and bleeding. Treat the underlying cause urgently.
A. Aspirin causes qualitative platelet dysfunction, not this global consumptive profile.
B. This does not explain low platelets and low fibrinogen.
D. ITP typically causes isolated thrombocytopenia without this coagulation factor consumption pattern.
- Treat the underlying cause urgently.
- A low fibrinogen supports severe rapidly evolving DIC but normal fibrinogen does not exclude early DIC.
- D-dimer indicates breakdown of cross-linked fibrin but is not specific for DIC.
Q78. A patient has lifelong intermittent jaundice, splenomegaly and a family history of similar symptoms. The blood film shows spherocytes and the direct antiglobulin test is negative. What is most likely?
Appeared in (recall papers): September 2018; September 2019
A. Autoimmune haemolytic anaemia
B. Aplastic anaemia
C. Iron deficiency alone
D. Hereditary spherocytosis
Answer and explanation
D. Hereditary spherocytosis
An inherited red-cell membrane disorder causes splenic haemolysis and spherocytes. Spherocytes are not specific for hereditary disease.
A. This commonly has a positive direct antiglobulin test.
B. Marrow failure does not explain this haemolytic pattern.
C. This causes microcytosis rather than the characteristic inherited spherocytic haemolysis.
- Spherocytes are not specific for hereditary disease.
- Use membrane testing, such as eosin-5-maleimide binding, in the appropriate diagnostic pathway.
- Splenic trapping promotes extravascular destruction of less deformable spherocytes.
Q79. A patient taking aspirin and clopidogrel has wound oozing despite a normal platelet count and normal routine PT/aPTT. What mechanism best explains this?
Appeared in (recall papers): January 2018; January 2019; January 2020; January 2021; May 2022; 2022 or 2023 (session not specified); January 2026
A. Consumption of all coagulation factors
B. Congenital factor VIII absence
C. Qualitative platelet dysfunction
D. Splenic platelet sequestration alone
Answer and explanation
C. Qualitative platelet dysfunction
These drugs inhibit platelet activation through different pathways without necessarily lowering platelet count. Normal platelet count does not establish normal platelet function.
A. This would suggest a consumptive coagulopathy with a different laboratory pattern.
B. This typically prolongs aPTT and does not result from these medicines.
D. This principally lowers circulating platelet numbers.
- Normal platelet count does not establish normal platelet function.
- PT and aPTT do not measure the full primary haemostatic response.
- Aspirin inhibits platelet cyclo-oxygenase, whereas clopidogrel blocks P2Y12 signalling.
Q80. A patient with portal hypertension has splenomegaly and thrombocytopenia. Marrow shows preserved or increased megakaryocytes. Which mechanism can explain the low platelet count?
Appeared in (recall papers): April 2019; January 2021; April 2021; Paper/session not recorded in source
A. Complete absence of megakaryocytes
B. Failure of all haematopoiesis
C. Selective loss of factor VII
D. Splenic sequestration of platelets
Answer and explanation
D. Splenic sequestration of platelets
An enlarged spleen can retain an increased proportion of circulating platelets. Thrombocytopenia in cirrhosis is multifactorial.
A. This contradicts the marrow finding.
B. The stem does not describe global marrow failure.
C. A clotting factor deficiency does not directly explain platelet sequestration.
- Thrombocytopenia in cirrhosis is multifactorial.
- Reduced thrombopoietin and other mechanisms may coexist with sequestration.
- An increased marrow megakaryocyte population argues against simple absent platelet production.
Q81. A boy has recurrent haemarthroses and an isolated prolonged aPTT that corrects on mixing with normal plasma. Factor VIII activity is markedly reduced. Which diagnosis is most likely?
Appeared in (recall papers): January 2020; September 2020
A. Immune thrombocytopenia
B. Haemophilia A
C. Haemophilia B
D. Factor VII deficiency
Answer and explanation
B. Haemophilia A
Factor VIII deficiency causes haemophilia A. Deep tissue and joint bleeding favour a coagulation factor disorder.
A. This affects platelet numbers and usually causes mucocutaneous bleeding.
C. Haemophilia B is factor IX deficiency.
D. This primarily prolongs PT.
- Deep tissue and joint bleeding favour a coagulation factor disorder.
- Acquired factor VIII inhibitors can affect either sex and need a different interpretation of mixing tests.
- Factor VIII acts as a cofactor for activated factor IX.
Q82. Which early blood-count change is commonly seen after splenectomy?
Appeared in (recall papers): January 2020
A. Permanent absence of all leukocytes
B. Reactive thrombocytosis
C. Obligatory severe thrombocytopenia
D. Cessation of erythropoiesis
Answer and explanation
B. Reactive thrombocytosis
Loss of splenic sequestration and the postoperative response commonly raise platelet counts. The count pattern does not replace assessment for postoperative complications.
A. Splenectomy does not abolish leukocyte production.
C. A sustained fall is not the usual uncomplicated response.
D. Bone marrow erythropoiesis continues.
- The count pattern does not replace assessment for postoperative complications.
- Blood-film changes and platelet count changes are different questions.
- Reactive thrombocytosis does not by itself diagnose a myeloproliferative neoplasm.
Q83. A previously sensitised person develops an indurated tuberculin skin test reaction after 48–72 hours. Which immune mechanism is responsible?
Appeared in (recall papers): January 2021
A. IgE-mediated immediate hypersensitivity
B. Preformed IgM causing intravascular haemolysis
C. T-cell-mediated type IV hypersensitivity
D. Immune-complex deposition alone
Answer and explanation
C. T-cell-mediated type IV hypersensitivity
Sensitised T cells drive a delayed inflammatory reaction. A positive test indicates sensitisation, not proof of active tuberculosis.
A. This occurs rapidly through mast-cell mediators.
B. This is not the tuberculin mechanism.
D. This is a type III mechanism, not the classic tuberculin response.
- A positive test indicates sensitisation, not proof of active tuberculosis.
- Interpretation depends on the clinical context and testing method.
- Delayed hypersensitivity is mediated by sensitised lymphocytes rather than newly formed local IgE.
Q84. A basal cell carcinoma is excised. Which histological finding directly indicates residual local tumour risk at the operative boundary?
Appeared in (recall papers): September 2017; January 2021; Paper/session not recorded in source
A. Normal epidermis over the specimen
B. Tumour at an excision margin
C. Absence of melanin
D. A completely tumour-free assessed margin
Answer and explanation
B. Tumour at an excision margin
An involved margin means the tumour reaches the edge of the specimen. BCC is usually locally destructive rather than distantly metastatic.
A. Normal surface epithelium does not establish margin clearance.
C. Pigment absence does not determine completeness of excision.
D. A clear margin is preferable, although it does not guarantee zero recurrence.
- BCC is usually locally destructive rather than distantly metastatic.
- Recurrence risk also depends on site, subtype, size and previous treatment.
- An aggressive infiltrative histological subtype increases concern for local recurrence.
Q85. An untreated hyperthyroid patient becomes febrile, confused and markedly tachycardic after an operation, with atrial fibrillation and cardiovascular instability. Which diagnosis should be suspected?
Appeared in (recall papers): January 2021
A. Uncomplicated thyrotoxicosis
B. Thyroid storm
C. Adrenal crisis alone
D. Myxoedema coma
Answer and explanation
B. Thyroid storm
A hyperthyroid patient with acute fever, marked tachyarrhythmia, encephalopathy and circulatory decompensation may have thyroid storm. This is a clinical emergency requiring coordinated treatment.
A. The acute systemic decompensation is more severe than uncomplicated hyperthyroidism.
C. Adrenal crisis can cause shock but does not best explain the pronounced thyrotoxic tachyarrhythmia pattern.
D. Severe hypothyroid decompensation more typically causes hypothermia and bradycardia.
- This is a clinical emergency requiring coordinated treatment.
- Thyroid hormone concentration alone does not distinguish storm from uncomplicated thyrotoxicosis.
- Infection and surgery are recognised precipitants of thyroid storm.
Q86. A patient with recurrent upper urinary infection has irregularly scarred, asymmetrically small kidneys and calyceal distortion. Which pathological process best fits?
Appeared in (recall papers): 2021 (session not specified)
A. Minimal change disease
B. Acute tubular necrosis alone
C. Chronic pyelonephritis
D. Autosomal dominant polycystic kidney disease
Answer and explanation
C. Chronic pyelonephritis
Recurrent infection and reflux-associated injury can produce irregular renal and calyceal scarring. Consider reflux and obstructive factors in the underlying history.
A. This does not explain distorted calyces and cortical scars.
B. ATN does not produce this characteristic chronic irregular scarring pattern.
D. ADPKD usually produces enlarged cystic kidneys.
- Consider reflux and obstructive factors in the underlying history.
- A single uncomplicated lower UTI does not establish chronic pyelonephritis.
- Reflux-associated scarring often affects renal poles.
Q87. A thyroid malignancy with capsular and vascular invasion develops a distant bone metastasis. Which subtype classically spreads haematogenously in this way?
Appeared in (recall papers): April 2021
A. Benign follicular adenoma
B. Follicular thyroid carcinoma
C. Papillary microcarcinoma without invasion
D. Hashimoto thyroiditis
Answer and explanation
B. Follicular thyroid carcinoma
Vascular invasion and distant haematogenous spread are characteristic of follicular carcinoma. Follicular carcinoma cannot be diagnosed from cytology alone by demonstrating invasion.
A. An adenoma lacks capsular and vascular invasion and does not metastasise.
C. This does not best match the specified vascular invasive pattern.
D. This is an autoimmune inflammatory disorder rather than a metastatic carcinoma.
- Follicular carcinoma cannot be diagnosed from cytology alone by demonstrating invasion.
- Papillary carcinoma more commonly involves regional nodes.
- Follicular adenoma and carcinoma may have similar cytology; invasion is decisive.
Q88. Which microscopic finding establishes acute appendicitis in the appropriate clinical setting?
Appeared in (recall papers): April 2021
A. Isolated serosal adipose tissue
B. Goblet cells in normal mucosa
C. Amyloid in vessel walls alone
D. Neutrophils infiltrating the muscularis propria
Answer and explanation
D. Neutrophils infiltrating the muscularis propria
Neutrophilic mural inflammation is the defining histological feature. Mucosal inflammation alone needs careful interpretation.
A. This does not establish appendicitis.
B. Goblet cells are normal intestinal epithelial cells.
C. This is not the defining acute appendicitis lesion.
- Mucosal inflammation alone needs careful interpretation.
- Transmural suppuration can progress to gangrene and perforation.
- Muscularis propria is the true muscle wall and differs from the thin muscularis mucosae.
Q89. A worker with prolonged hardwood dust exposure develops a malignant gland-forming tumour in the nasal cavity. Which tumour has a recognised occupational association?
Appeared in (recall papers): April 2021
A. Osteosarcoma
B. Sinonasal adenocarcinoma
C. Pleural mesothelioma
D. Renal clear-cell carcinoma
Answer and explanation
B. Sinonasal adenocarcinoma
Wood dust exposure is associated with sinonasal adenocarcinoma. Occupational history can identify relevant carcinogen exposure.
A. This is not a sinonasal gland-forming epithelial malignancy.
C. Mesothelioma is classically linked to asbestos exposure.
D. This is not the characteristic tumour associated with inhaled hardwood dust.
- Occupational history can identify relevant carcinogen exposure.
- An association does not prove causation in an individual patient.
- The sinonasal intestinal-type subtype is especially associated with wood dust.
Q90. Among the following findings in a newly excised localised primary melanoma, which is relatively favourable?
Appeared in (recall papers): April 2018; September 2021; 2021 (session not specified)
A. Lymphovascular invasion
B. Surface ulceration
C. Breslow thickness of 0.6 mm
D. Satellite deposits
Answer and explanation
C. Breslow thickness of 0.6 mm
A thin primary generally has a better outlook than a thick or otherwise high-risk lesion. Thickness is measured vertically in millimetres.
A. This is an adverse feature.
B. Ulceration is an adverse prognostic feature.
D. These indicate regional spread rather than a favourable primary feature.
- Thickness is measured vertically in millimetres.
- Nodal and distant disease alter overall stage and prognosis.
- Clark level describes anatomical level, while Breslow measures thickness in millimetres.
Q91. An older adult has progressive painless jaundice, weight loss and a pancreatic head mass causing distal bile duct obstruction. Which diagnosis is most likely?
Appeared in (recall papers): April 2019; May 2022; January 2023
A. Gilbert syndrome
B. Acute uncomplicated cystitis
C. Benign unconjugated hyperbilirubinaemia alone
D. Pancreatic ductal adenocarcinoma
Answer and explanation
D. Pancreatic ductal adenocarcinoma
A pancreatic head carcinoma can obstruct the distal common bile duct. Head lesions may cause jaundice earlier than body or tail lesions.
A. This does not cause a mass or progressive obstructive jaundice.
B. This is unrelated to biliary obstruction.
C. The structural obstructing lesion requires a different explanation.
- Head lesions may cause jaundice earlier than body or tail lesions.
- Painless jaundice is a warning sign, not a standalone tissue diagnosis.
- Pancreatic body and tail cancers may remain silent until more advanced disease.
Q92. Which red-cell finding is characteristic of reduced splenic filtering after splenectomy?
Appeared in (recall papers): January 2023
A. Auer rods
B. Reed–Sternberg cells
C. Howell–Jolly bodies
D. Keratin pearls
Answer and explanation
C. Howell–Jolly bodies
Nuclear remnants persist when splenic removal is absent or impaired. Target cells may also appear after splenectomy.
A. These are myeloid blast inclusions, not a red-cell filtering change.
B. These are lymphoma-associated large lymphoid cells.
D. These are squamous tumour structures.
- Target cells may also appear after splenectomy.
- Blood-film morphology differs from reactive thrombocytosis.
- Howell–Jolly bodies are DNA remnants within erythrocytes.
Q93. Which reaction is directly catalysed by thrombin during clot formation?
Appeared in (recall papers): January 2024
A. Conversion of plasminogen to erythropoietin
B. Destruction of all platelets
C. Synthesis of immunoglobulin
D. Conversion of fibrinogen to fibrin
Answer and explanation
D. Conversion of fibrinogen to fibrin
Thrombin cleaves fibrinogen, permitting fibrin polymer formation. Factor XIII stabilises fibrin through cross-linking.
A. These are unrelated proteins and pathways.
B. Thrombin activates platelets rather than universally destroying them.
C. Antibodies are produced by plasma cells.
- Factor XIII stabilises fibrin through cross-linking.
- Thrombin has additional regulatory and platelet-activating functions.
- Prothrombin is the inactive precursor of thrombin.
Q94. A patient years after total gastrectomy has anaemia, paraesthesia and reduced vitamin B12. Which blood-film finding is most likely?
Appeared in (recall papers): September 2017; January 2020; January 2021; September 2021; January 2024
A. Isolated sickled red cells
B. Numerous spherocytes as the defining feature
C. Auer rods in mature erythrocytes
D. Macro-ovalocytes and hypersegmented neutrophils
Answer and explanation
D. Macro-ovalocytes and hypersegmented neutrophils
B12 deficiency impairs DNA synthesis and produces megaloblastic morphology. Loss of gastric intrinsic factor can impair B12 absorption.
A. Sickling reflects an abnormal haemoglobin disorder.
B. Spherocytes suggest a membrane or immune haemolytic process.
C. Auer rods occur in myeloid blasts, not mature red cells.
- Loss of gastric intrinsic factor can impair B12 absorption.
- Iron deficiency can coexist and mask macrocytosis.
- Neurological B12 deficiency can occur even without striking macrocytosis.
Q95. Which factor participates in the intrinsic tenase complex with activated factor VIII to activate factor X?
Appeared in (recall papers): May 2024; April 2025
A. Factor VII alone
B. Activated factor IX
C. Plasmin
D. Fibrinogen
Answer and explanation
B. Activated factor IX
IXa and VIIIa form intrinsic tenase on a phospholipid surface. VIII is a cofactor; IX is a protease in the complex.
A. VIIa works with tissue factor in the extrinsic initiation pathway.
C. Plasmin mediates fibrin breakdown.
D. Fibrinogen is the substrate converted to fibrin.
- VIII is a cofactor; IX is a protease in the complex.
- Both VIII and IX belong to the intrinsic pathway, so they cannot be competing single-best answers to an unqualified pathway question.
- Tissue factor with VIIa initiates the extrinsic pathway in the classical teaching model.
Q96. After treatment for medullary thyroid carcinoma, which marker is characteristic for biochemical surveillance?
Appeared in (recall papers): April 2026
A. Calcitonin
B. Prostate-specific antigen
C. Alpha-fetoprotein
D. Thyroglobulin as the defining marker
Answer and explanation
A. Calcitonin
Medullary carcinoma arises from calcitonin-producing C cells. CEA may also contribute to medullary carcinoma monitoring.
B. PSA is used in prostate disease.
C. AFP is associated with selected germ-cell and liver tumours.
D. Thyroglobulin is associated with differentiated follicular-cell thyroid tissue, not the defining medullary lineage.
- CEA may also contribute to medullary carcinoma monitoring.
- A marker result must be interpreted with the clinical and imaging assessment.
- Medullary carcinoma may be sporadic or associated with inherited RET variants.
Q97. Which virus is a recognised cause of hepatocellular carcinoma among these choices?
Appeared in (recall papers): Paper/session not recorded in source
A. Human papillomavirus
B. Human T-cell lymphotropic virus 1
C. Hepatitis B virus
D. Epstein–Barr virus
Answer and explanation
C. Hepatitis B virus
Chronic HBV infection is an established HCC risk factor. HCV is another important HCC risk factor.
A. HPV is associated with several anogenital and oropharyngeal cancers, not the classic HBV-HCC relationship.
B. HTLV-1 is associated with adult T-cell leukaemia/lymphoma.
D. EBV is linked to selected lymphomas and other tumours rather than this principal hepatotropic association.
- HCV is another important HCC risk factor.
- HBV-associated HCC can occur without established cirrhosis.
- Chronic viral hepatitis and cirrhosis require risk-based liver surveillance pathways.
Q98. A patient with actively bleeding DIC has a markedly low fibrinogen concentration despite initial resuscitation. Which blood component is a concentrated source of fibrinogen?
Appeared in (recall papers): January 2026
A. Washed red cells
B. Normal saline
C. Albumin solution
D. Cryoprecipitate
Answer and explanation
D. Cryoprecipitate
Cryoprecipitate contains concentrated fibrinogen and can support replacement in severe bleeding with hypofibrinogenaemia. Component treatment is guided by bleeding and laboratory results.
A. Red cells principally restore oxygen-carrying capacity.
B. Saline does not supply coagulation proteins.
C. Albumin does not replace fibrinogen.
- Component treatment is guided by bleeding and laboratory results.
- Treating the precipitating cause remains essential.
- Fibrinogen concentrate is another replacement option in some protocols and settings.
Q99. Within the liver, which cell type is an important source of factor VIII?
Appeared in (recall papers): September 2024; January 2026; April 2026
A. Liver sinusoidal endothelial cells
B. Podocytes
C. Mature erythrocytes
D. Hepatocytes as the exclusive source
Answer and explanation
A. Liver sinusoidal endothelial cells
Human hepatic sinusoidal endothelial cells, rather than hepatocytes, contain and produce factor VIII. The statement that factor VIII is never made in the liver is incorrect.
B. Podocytes are glomerular epithelial cells, not the hepatic source.
C. Mature red cells do not synthesise factor VIII.
D. Most coagulation proteins are hepatocyte-derived, but factor VIII has an important endothelial source.
- The statement that factor VIII is never made in the liver is incorrect.
- Distinguish an organ from the particular cell type within it.
- Endothelial origin helps explain why organ-level factor synthesis mnemonics can mislead.
Q100. A patient with sickle cell disease has culture-confirmed bacterial septic arthritis. Which organism remains an important common cause and should not be displaced automatically by the osteomyelitis mnemonic?
Appeared in (recall papers): September 2018
A. Epstein–Barr virus
B. Candida as the universal organism
C. Staphylococcus aureus
D. Plasmodium falciparum
Answer and explanation
C. Staphylococcus aureus
S. aureus is a major cause of septic arthritis, including in sickle cell disease. Separate septic arthritis from osteomyelitis.
A. EBV is not a typical pyogenic joint pathogen.
B. Fungal arthritis can occur but is not the universal explanation.
D. This causes malaria, not a typical bacterial septic arthritis.
- Separate septic arthritis from osteomyelitis.
- Culture and aspiration guide organism-specific treatment.
- An acutely hot swollen joint requires urgent aspiration and microbiological assessment.
Q101. Which bacterial genus has a classic increased association with osteomyelitis in sickle cell disease?
Appeared in (recall papers): January 2021; April 2025
A. Neisseria gonorrhoeae as the characteristic association
B. Salmonella
C. Clostridioides difficile
D. Helicobacter pylori
Answer and explanation
B. Salmonella
Salmonella is an important recognised association in sickle-cell osteomyelitis. Staphylococcus aureus is also an important cause.
A. Gonococcal disease is not the classic sickle-cell osteomyelitis association.
C. C. difficile causes antibiotic-associated colitis.
D. H. pylori predominantly colonises the stomach.
- Staphylococcus aureus is also an important cause.
- Relative frequencies vary by population; the mnemonic cannot replace culture.
- Bone infarction and infection can overlap clinically in sickle cell disease.
Q102. Which activated coagulation factor is not a direct serine-protease target of antithrombin?
Appeared in (recall papers): May 2022; May 2023
A. Thrombin, factor IIa
B. Factor IXa
C. Factor Xa
D. Factor VIIIa
Answer and explanation
D. Factor VIIIa
VIIIa is a cofactor rather than a serine protease target of antithrombin. Heparin enhances antithrombin activity.
A. Thrombin is a principal antithrombin target.
B. IXa is among the activated proteases inhibited by antithrombin.
C. Xa is a major antithrombin target.
- Heparin enhances antithrombin activity.
- Antithrombin inhibits coagulation proteases; it does not activate them.
- Factor VIIIa is a cofactor; factors IIa, IXa and Xa are proteases.
Q103. Warfarin impairs production of functional forms of which coagulation factors?
Appeared in (recall papers): September 2022; September 2024; April 2026
A. II, VII, IX and X
B. VIII and XI only
C. All circulating proteins equally
D. I, V, VIII and XIII
Answer and explanation
A. II, VII, IX and X
These are the vitamin K-dependent procoagulant factors. Proteins C and S are also vitamin K-dependent.
B. Neither is the defining warfarin-dependent set.
C. Warfarin does not nonspecifically suppress all plasma proteins.
D. This is not the vitamin K-dependent factor set.
- Proteins C and S are also vitamin K-dependent.
- Warfarin inhibits vitamin K recycling rather than directly inhibiting circulating factor IX.
- Functional deficiency reflects impaired gamma-carboxylation of vitamin K-dependent proteins.
Q104. A patient with chronic haemolytic anaemia develops dark gallstones. Which material predominates in the characteristic stone type?
Appeared in (recall papers): September 2022; January 2023; May 2024
A. Magnesium ammonium phosphate
B. Pure cholesterol only
C. Bilirubin pigment, principally calcium bilirubinate
D. Cystine
Answer and explanation
C. Bilirubin pigment, principally calcium bilirubinate
Increased bilirubin load from haemolysis favours black pigment stones. Chronic haemolysis increases biliary bilirubin delivery.
A. This describes struvite urinary stones.
B. Cholesterol stones have a different principal composition.
D. Cystine is associated with inherited urinary stone disease.
- Chronic haemolysis increases biliary bilirubin delivery.
- Pigment and cholesterol stone mechanisms should be distinguished.
- Black pigment stones are associated with chronic haemolysis.
Q105. Which renal cell population is the principal physiological source of erythropoietin in adults?
Appeared in (recall papers): May 2024
A. Peritubular interstitial fibroblast-like cells
B. Juxtaglomerular granular cells
C. Podocytes
D. Macula densa cells
Answer and explanation
A. Peritubular interstitial fibroblast-like cells
Specialised renal interstitial cells respond to oxygen availability by regulating EPO production. CKD anaemia is often partly due to inadequate EPO production.
B. These principally secrete renin.
C. These form part of the glomerular filtration barrier.
D. These sense tubular solute delivery as part of tubuloglomerular feedback.
- CKD anaemia is often partly due to inadequate EPO production.
- Iron deficiency and inflammation can coexist.
- Renin-producing granular cells are part of the juxtaglomerular apparatus.
Q106. Which substance is stored in platelet dense, or delta, granules?
Appeared in (recall papers): January 2025
A. Fibrinogen
B. Serotonin
C. Von Willebrand factor
D. Platelet-derived growth factor
Answer and explanation
B. Serotonin
Dense granules contain small molecules including serotonin, ADP, ATP and calcium. Dense granules mainly store small molecules.
A. Fibrinogen is associated with alpha granules rather than the defining dense-granule contents.
C. VWF is associated with platelet alpha granules.
D. PDGF is an alpha-granule protein.
- Dense granules mainly store small molecules.
- Alpha granules contain proteins involved in adhesion, coagulation and repair.
- ADP released from dense granules amplifies platelet activation.
Q107. Which immunoglobulin predominates in secretions such as saliva and intestinal secretions?
Appeared in (recall papers): 2022 or 2023 (session not specified); January 2023
A. IgE
B. Secretory IgA
C. Pentameric IgM as the dominant normal secretory class
D. IgD
Answer and explanation
B. Secretory IgA
Dimeric IgA with secretory component is important in mucosal defence. Secretory component protects IgA in mucosal environments.
A. IgE is important in immediate allergy and anti-parasite responses.
C. IgM is mainly intravascular and is not the predominant normal mucosal isotype.
D. IgD mainly serves as a receptor on naïve B cells.
- Secretory component protects IgA in mucosal environments.
- Serum IgA is predominantly monomeric.
- The secretory IgA dimer contains a joining chain.
Q108. Minutes after re-exposure to an allergen, a patient develops urticaria, wheeze and hypotension. Which antibody class mediates the classic type I mechanism?
Appeared in (recall papers): September 2017; April 2021; 2022 or 2023 (session not specified); January 2023; May 2024; April 2025; April 2026
A. IgA
B. IgG as the defining type I isotype
C. IgD
D. IgE
Answer and explanation
D. IgE
Allergen cross-links IgE bound to high-affinity receptors on mast cells and basophils. Clinical anaphylaxis is treated urgently regardless of whether an IgE mechanism is demonstrated.
A. IgA mainly supports mucosal defence.
B. Type I allergy is classically IgE-mediated, although anaphylaxis can occur through other mechanisms.
C. IgD primarily functions as a B-cell surface receptor.
- Clinical anaphylaxis is treated urgently regardless of whether an IgE mechanism is demonstrated.
- Do not confuse immediate latex allergy with delayed contact allergy.
- Allergen-specific IgE sensitisation does not necessarily produce symptoms on every exposure.
Q109. Which tissue cell releases histamine after allergen cross-links surface-bound IgE in an immediate allergic reaction?
Appeared in (recall papers): September 2017; September 2022; Paper/session not recorded in source
A. Mature erythrocyte
B. Fibroblast
C. Mast cell
D. Osteoclast
Answer and explanation
C. Mast cell
IgE receptor cross-linking triggers mast-cell mediator release. Basophils also express high-affinity IgE receptors.
A. Red cells do not mediate this IgE degranulation response.
B. Fibroblasts principally produce extracellular matrix.
D. Osteoclasts resorb bone.
- Basophils also express high-affinity IgE receptors.
- Eosinophils can contribute to later allergic inflammation.
- Mast cells reside in tissues, whereas basophils circulate in blood.
Q110. Which cell is specialised for secretion of immunoglobulin?
Appeared in (recall papers): September 2020; Paper/session not recorded in source
A. Platelet
B. Neutrophil
C. Erythrocyte
D. Plasma cell
Answer and explanation
D. Plasma cell
Plasma cells are differentiated B-lineage cells specialised for antibody secretion. A plasma cell has abundant rough endoplasmic reticulum.
A. Platelets mediate haemostasis and do not secrete immunoglobulins.
B. Neutrophils are phagocytic granulocytes.
C. Mature red cells transport respiratory gases.
- A plasma cell has abundant rough endoplasmic reticulum.
- B-cell receptors and secreted antibodies are related but distinct forms.
- Plasma-cell neoplasms can produce a monoclonal immunoglobulin or light chain.
Q111. An itchy eczematous rash develops 48 hours after contact with a sensitising glove chemical. Which mechanism is responsible?
Appeared in (recall papers): January 2021; May 2023
A. Type IV T-cell-mediated hypersensitivity
B. Immediate IgE-mediated degranulation alone
C. C3b-mediated opsonisation alone
D. Direct ABO antibody haemolysis
Answer and explanation
A. Type IV T-cell-mediated hypersensitivity
Allergic contact dermatitis is a delayed cellular immune reaction. Not every glove reaction is allergy; irritant dermatitis is also common.
B. This typically occurs rapidly and is a different form of allergy.
C. Opsonisation is not the defining mechanism of allergic contact dermatitis.
D. This causes an incompatible transfusion reaction.
- Not every glove reaction is allergy; irritant dermatitis is also common.
- Patch testing assesses delayed contact sensitisation.
- The delayed response commonly peaks after the immediate-allergy time window.
Q112. An in-vitro allergy blood test measures antibodies directed against a specified allergen. Which immunoglobulin is measured in a specific-IgE assay?
Appeared in (recall papers): January 2023
A. IgA
B. IgD
C. IgE
D. IgM
Answer and explanation
C. IgE
Specific-IgE assays assess IgE sensitisation to the chosen allergen. A positive result shows sensitisation and must match the clinical history.
A. IgA testing addresses different immune questions.
B. IgD is not the target of a specific-IgE assay.
D. IgM is not the defining target of this test.
- A positive result shows sensitisation and must match the clinical history.
- The historic RAST term does not mean every modern assay uses a radioisotope.
- Allergy testing should be selected according to the suspected trigger and reaction history.
Q113. Which description best fits secreted IgM?
Appeared in (recall papers): May 2023; April 2025
A. The antibody class bound to mast cells in type I allergy
B. A monomer that is the main placental antibody
C. Usually pentameric and does not cross the placenta
D. The principal dimer in mucosal secretions
Answer and explanation
C. Usually pentameric and does not cross the placenta
Secreted IgM is a large pentamer and is not transported across the placenta like IgG. Membrane IgM on B cells is monomeric.
A. This describes IgE.
B. This describes important features of IgG rather than secreted IgM.
D. This describes secretory IgA.
- Membrane IgM on B cells is monomeric.
- Separate secreted antibody structure from membrane receptor form.
- IgG crosses the placenta through receptor-mediated transport.
Q114. Which complement components form the membrane attack complex?
Appeared in (recall papers): May 2023
A. C5b–C9
B. C3b alone
C. IgE and histamine
D. C5a–C9
Answer and explanation
A. C5b–C9
C5b initiates assembly of the terminal membrane attack complex. C5 cleavage generates C5a and C5b with different functions.
B. C3b is chiefly an opsonin and convertase component.
C. These are not terminal complement proteins.
D. C5a is a soluble inflammatory mediator, not the initiating structural component.
- C5 cleavage generates C5a and C5b with different functions.
- Terminal complex formation can damage susceptible cell membranes.
- Defects in terminal complement components increase susceptibility to selected Neisseria infections.
Q115. Which complement fragment is a potent neutrophil chemoattractant?
Appeared in (recall papers): May 2023
A. C5a
B. IgD
C. Fibrinogen
D. C5b
Answer and explanation
A. C5a
C5a recruits and activates inflammatory cells. C5a is also an anaphylatoxin.
B. IgD is an immunoglobulin rather than a complement fragment.
C. Fibrinogen is a coagulation protein.
D. C5b initiates the terminal membrane attack complex.
- C5a is also an anaphylatoxin.
- Do not interchange C5a and C5b.
- Chemotaxis means directed cell movement along a chemical gradient.
Q116. Which complement component deposited on a microbial surface promotes phagocytosis?
Appeared in (recall papers): May 2023
A. Thrombin
B. Histamine
C. C5b–C9 alone
D. C3b
Answer and explanation
D. C3b
Surface C3b is recognised by complement receptors and acts as an opsonin. Opsonins improve recognition by phagocytes.
A. Thrombin functions in coagulation.
B. Histamine is an inflammatory mediator, not a complement opsonin.
C. The terminal complex chiefly forms membrane pores.
- Opsonins improve recognition by phagocytes.
- IgG can also act as an opsonin through Fc receptors.
- Opsonisation promotes ingestion rather than directly defining membrane lysis.
Q117. During a typical primary antibody response, which isotype is initially secreted before substantial class-switched IgG production?
Appeared in (recall papers): Paper/session not recorded in source
A. IgE invariably first
B. IgM
C. IgD as the major secreted early antibody
D. IgG must precede IgM
Answer and explanation
B. IgM
IgM is produced early before subsequent class switching in responding B cells. Memory responses can produce rapid class-switched antibodies.
A. IgE production requires an appropriate class-switching response.
C. IgD is chiefly a membrane receptor rather than the major early secreted class.
D. This reverses the usual primary response sequence.
- Memory responses can produce rapid class-switched antibodies.
- IgM may precede several class-switched isotypes; distinguish a primary response from a memory response.
- Class switching changes the antibody constant region while preserving antigen specificity.
Q118. A temporal artery biopsy from an older patient with new headache and jaw claudication shows inflammation centred on the internal elastic lamina with multinucleated giant cells. What pattern is characteristic?
Appeared in (recall papers): September 2022; 2022 or 2023 (session not specified); January 2023; April 2026
A. Malignant endothelial proliferation
B. Non-inflammatory medial calcification alone
C. Purely neutrophilic venulitis
D. Granulomatous arteritis
Answer and explanation
D. Granulomatous arteritis
Giant cell arteritis produces granulomatous inflammation with macrophages and T cells, often disrupting the elastic lamina. Lesions can be segmental, creating skip areas.
A. This would suggest a vascular neoplasm.
B. Calcification alone does not explain the inflammatory syndrome.
C. This does not describe the typical large-artery lesion.
- Lesions can be segmental, creating skip areas.
- Urgent treatment may be needed to prevent visual loss; do not await biopsy in a high-risk presentation.
- Giant cell arteritis predominantly affects medium and large arteries.
Q119. A patient has persistent hypercalcaemia, low phosphate and a raised PTH that is inappropriate for the calcium level. Which diagnosis best fits?
Appeared in (recall papers): January 2023
A. Humoral hypercalcaemia of malignancy from PTHrP
B. Vitamin D intoxication
C. Primary hyperparathyroidism
D. Uncomplicated secondary hyperparathyroidism in CKD
Answer and explanation
C. Primary hyperparathyroidism
Autonomous parathyroid secretion causes PTH-dependent hypercalcaemia. Interpret PTH against the simultaneous calcium concentration.
A. This usually suppresses endogenous PTH.
B. This is generally PTH-independent and suppresses PTH.
D. Calcium is commonly normal or low; hypercalcaemia requires further explanation.
- Interpret PTH against the simultaneous calcium concentration.
- Urinary calcium assessment can help distinguish familial hypocalciuric hypercalcaemia.
- Inappropriately non-suppressed PTH is important when evaluating hypercalcaemia.
Q120. A patient with fatigable weakness, acetylcholine receptor antibodies and an anterior mediastinal epithelial tumour has which recognised association?
Appeared in (recall papers): May 2024
A. Oesophageal leiomyoma
B. Thymoma
C. Posterior mediastinal schwannoma
D. Bronchogenic cyst
Answer and explanation
B. Thymoma
Thymoma has a well-established association with myasthenia gravis. Most myasthenia patients do not necessarily have a thymoma.
A. This is not the usual anterior mediastinal tumour associated with myasthenia.
C. This is a nerve sheath tumour and not the characteristic association.
D. A congenital cyst is not the characteristic thymic epithelial tumour.
- Most myasthenia patients do not necessarily have a thymoma.
- Thymoma is an epithelial neoplasm with variable accompanying lymphocytes.
- The thymus is in the anterior mediastinum.
Q121. Which lymphoma has a characteristic association with coeliac disease?
Appeared in (recall papers): September 2019
A. Enteropathy-associated T-cell lymphoma
B. Classic Hodgkin lymphoma as the defining intestinal association
C. Burkitt lymphoma as the specific association
D. Gastric MALT lymphoma
Answer and explanation
A. Enteropathy-associated T-cell lymphoma
EATL is an intestinal T-cell malignancy associated with coeliac disease. EATL and gastric MALT lymphoma have different cell lineages.
B. This is not the characteristic coeliac-associated entity.
C. Burkitt lymphoma is not the defining coeliac-associated lymphoma.
D. This is a B-cell marginal zone lymphoma commonly associated with H. pylori.
- EATL and gastric MALT lymphoma have different cell lineages.
- New systemic symptoms in refractory coeliac disease require assessment.
- Refractory coeliac disease is not synonymous with an established lymphoma.
Q122. The malignant Hodgkin/Reed–Sternberg cells of most classic Hodgkin lymphomas arise from which lineage?
Appeared in (recall papers): September 2019
A. Fibroblasts
B. Mature neutrophils
C. Germinal-centre B cells
D. Epithelial cells
Answer and explanation
C. Germinal-centre B cells
Classic Hodgkin lymphoma is usually a B-cell-derived neoplasm despite its altered B-cell expression programme. The background inflammatory cells may greatly outnumber malignant cells.
A. Fibroblasts may contribute to stroma but do not form the malignant HRS cells.
B. Neutrophils may be reactive background cells, not the malignant lineage.
D. Classic Hodgkin lymphoma is not a carcinoma.
- The background inflammatory cells may greatly outnumber malignant cells.
- Lineage and immunophenotype are related but not interchangeable.
- Reactive lymphocytes are not the same as malignant Hodgkin/Reed–Sternberg cells.
Q123. A gastric biopsy shows extranodal marginal zone lymphoma of MALT type. What is the malignant cell lineage?
Appeared in (recall papers): April 2021
A. Gastric epithelial cell
B. Macrophage
C. B lymphocyte
D. T lymphocyte
Answer and explanation
C. B lymphocyte
Gastric MALT lymphoma is a B-cell neoplasm. H. pylori is an important association.
A. An epithelial malignancy would be a carcinoma.
B. Macrophages are not the malignant lineage of this entity.
D. This is not the defining lineage of gastric MALT lymphoma.
- H. pylori is an important association.
- Selected localised H. pylori-associated cases respond to eradication therapy.
- Extranodal marginal zone lymphoma can occur outside the stomach.
Q124. A patient with weight loss and iron-deficiency anaemia has metastatic adenocarcinoma in a left supraclavicular lymph node. Which primary should be particularly considered?
Appeared in (recall papers): September 2021
A. Hodgkin lymphoma
B. Primary cutaneous squamous carcinoma of the scalp
C. Primary thyroid medullary carcinoma
D. Gastric carcinoma
Answer and explanation
D. Gastric carcinoma
A left supraclavicular node with metastatic adenocarcinoma and iron-deficiency anaemia is a classic clue to gastric malignancy. A Virchow node is not specific for the stomach.
A. Lymphoma does not produce metastatic adenocarcinoma cells in the node.
B. Scalp SCC drains to head and neck nodes and does not produce the specified adenocarcinoma.
C. This has a different lineage and marker profile and is not the classic abdominal Virchow-node association.
- A Virchow node is not specific for the stomach.
- Investigate the primary using clinical, imaging and pathological evidence.
- Left supraclavicular nodes receive lymphatic drainage related to the thoracic duct.
Q125. An older adult has anaemia, hypercalcaemia, multiple lytic bone lesions, a monoclonal protein and clonal marrow plasma cells. Which diagnosis best fits?
Appeared in (recall papers): May 2022; May 2023; May 2024; April 2026
A. Solitary plasmacytoma
B. Monoclonal gammopathy of undetermined significance
C. Multiple myeloma
D. Reactive polyclonal hypergammaglobulinaemia
Answer and explanation
C. Multiple myeloma
The combination demonstrates a systemic plasma-cell neoplasm with myeloma-related organ injury. A monoclonal spike alone does not establish symptomatic myeloma.
A. This does not explain multiple lesions and systemic marrow disease.
B. MGUS does not account for attributable myeloma-defining organ damage.
D. This does not produce a clonal marrow population and monoclonal pattern.
- A monoclonal spike alone does not establish symptomatic myeloma.
- Renal impairment and light-chain production are important additional features.
- Clonal plasma-cell percentage must be interpreted with myeloma-defining events.
Q126. In a compatible lymph-node biopsy, Hodgkin/Reed–Sternberg cells show which typical classic Hodgkin immunophenotype?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. CD30 positive, often CD15 positive
B. Myeloperoxidase positive as the defining marker
C. Cytokeratin positive as the defining marker
D. Strong CD3 as the defining tumour marker
Answer and explanation
A. CD30 positive, often CD15 positive
This is the typical immunophenotypic pattern of classic Hodgkin lymphoma. CD15 is not positive in every case.
B. MPO supports myeloid rather than classic Hodgkin differentiation.
C. Cytokeratin supports epithelial differentiation.
D. CD3 identifies T-cell differentiation rather than the typical HRS phenotype.
- CD15 is not positive in every case.
- Distinguish classic Hodgkin lymphoma from nodular lymphocyte-predominant B-cell lymphoma.
- CD30 positivity is not unique to classic Hodgkin lymphoma.
Q127. Which immune cell is strongly activated by interferon gamma in a cell-mediated response?
Appeared in (recall papers): April 2025
A. Erythrocyte
B. Macrophage
C. Plasma cell for immediate histamine release
D. Platelet as the defining target
Answer and explanation
B. Macrophage
IFN-gamma enhances macrophage activation and antimicrobial function. Activated T cells and NK cells can produce IFN-gamma.
A. Mature red cells are not the principal immune target of this cytokine.
C. Histamine release is a mast-cell or basophil function.
D. Platelet activation is not the principal answer in this context.
- Activated T cells and NK cells can produce IFN-gamma.
- Macrophage activation is central to granulomatous immune responses.
- Interferon gamma is a cytokine rather than an immunoglobulin.
Q128. A lymphoid neoplasm expresses CD20. Which lineage does this marker support?
Appeared in (recall papers): April 2026
A. T-cell lineage
B. B-cell lineage
C. Histiocytic lineage
D. Myeloid lineage
Answer and explanation
B. B-cell lineage
CD20 expression supports mature B-cell differentiation in an appropriate lymphoid neoplasm. Not every B-cell neoplasm is CD20 positive.
A. CD3 is a key T-lineage marker; CD20 is not the defining T-cell marker.
C. Histiocytic markers include CD68 and CD163 rather than CD20 as a defining lineage marker.
D. Myeloid differentiation is assessed using markers such as myeloperoxidase, not CD20 alone.
- Not every B-cell neoplasm is CD20 positive.
- A full morphology and immunophenotype panel is needed to name the lymphoma.
- Marker expression identifies lineage but rarely supplies a complete lymphoma diagnosis alone.
Q129. A skeletally mature adult has an eccentric lytic lesion extending to subchondral bone at the end of a long bone. Histology shows numerous osteoclast-like giant cells among neoplastic stromal cells. What is most likely?
Appeared in (recall papers): September 2016; January 2019; September 2021
A. Giant cell tumour of bone
B. Osteoid osteoma
C. Osteochondroma
D. Ewing sarcoma
Answer and explanation
A. Giant cell tumour of bone
The epiphyseal-subchondral location and histological pattern support GCT. The neoplastic component is the stromal cell population.
B. This is typically a small nidus-forming lesion.
C. This is an exophytic cartilage-capped bone lesion.
D. Ewing sarcoma usually affects younger patients and contains small round tumour cells.
- The neoplastic component is the stromal cell population.
- GCT can be locally aggressive despite its usual classification.
- Most giant cell tumours arise after growth-plate closure.
Q130. A destructive metaphyseal bone tumour in an adolescent contains malignant cells directly producing osteoid. Which diagnosis is established?
Appeared in (recall papers): September 2017; May 2022; 2022 or 2023 (session not specified); April 2026
A. Giant cell tumour
B. Chondrosarcoma
C. Ewing sarcoma
D. Osteosarcoma
Answer and explanation
D. Osteosarcoma
Malignant osteoid production is the defining feature. The distal femur and proximal tibia are common sites.
A. GCT contains a stromal neoplasm with reactive osteoclast-like giant cells.
B. Chondrosarcoma produces malignant cartilage.
C. Ewing sarcoma is a small-round-cell tumour and does not characteristically form malignant osteoid.
- The distal femur and proximal tibia are common sites.
- Do not infer childhood Paget disease from an irrelevant family history.
- Reactive bone formation is not equivalent to malignant osteoid production.
Q131. A teenager has a painful diaphyseal lesion with a small-round-cell tumour and an EWSR1::FLI1 fusion. Which diagnosis is most likely?
Appeared in (recall papers): September 2020
A. Ewing sarcoma
B. Giant cell tumour
C. Osteochondroma
D. Conventional osteosarcoma
Answer and explanation
A. Ewing sarcoma
The common t(11;22) fusion and small-round-cell pattern support Ewing sarcoma. Imaging may show a laminated periosteal reaction.
B. This usually affects a skeletally mature epiphysis and has a different cellular pattern.
C. This is a benign cartilage-capped exostosis.
D. This requires malignant osteoid rather than the specified fusion pattern.
- Imaging may show a laminated periosteal reaction.
- A molecular result must fit the complete pathological assessment.
- The typical fusion joins EWSR1 on chromosome 22 to FLI1 on chromosome 11.
Q132. A young adult has nocturnal focal bone pain relieved by NSAIDs. CT shows a small cortical nidus under 2 cm with surrounding sclerosis. What is most likely?
Appeared in (recall papers): May 2022
A. Giant cell tumour
B. Osteoid osteoma
C. Osteosarcoma
D. Osteoblastoma
Answer and explanation
B. Osteoid osteoma
The small nidus and characteristic pain pattern support this benign osteoid-forming tumour. Benign osteoid alone cannot distinguish osteoid osteoma from osteoblastoma.
A. This typically forms a larger epiphyseal lytic lesion.
C. A destructive malignant osteoid-forming tumour has a different pattern.
D. This is generally larger and less characteristically relieved by NSAIDs.
- Benign osteoid alone cannot distinguish osteoid osteoma from osteoblastoma.
- Nidus size and the clinical-radiological context are important.
- Osteoid osteoma frequently has marked reactive sclerosis around a small nidus.
Q133. Which site is a common first distant metastatic destination for osteosarcoma?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Lungs
B. Brain
C. Regional lymph nodes
D. Peritoneum
Answer and explanation
A. Lungs
Osteosarcoma commonly spreads haematogenously to the lungs. Chest staging is important in the initial assessment.
B. Brain metastases can occur but are not the common initial distant destination.
C. Nodal spread is not the usual principal distant metastatic pattern.
D. Peritoneal deposits are not the typical first distant site.
- Chest staging is important in the initial assessment.
- Metastatic pattern differs from local extension into adjacent tissues.
- The presence of pulmonary metastasis changes stage and treatment planning.
Q134. After muscle trauma, a soft-tissue mass develops zonal maturation with peripheral mature bone and a less mature centre. Which diagnosis is favoured?
Appeared in (recall papers): January 2025
A. Rheumatoid nodule
B. Simple lipoma
C. Myositis ossificans
D. Conventional osteosarcoma
Answer and explanation
C. Myositis ossificans
Peripheral maturation is a characteristic pattern of post-traumatic heterotopic ossification. Early lesions can be difficult to distinguish from malignancy.
A. This shows necrobiotic material and palisading histiocytes rather than zonal ossification.
B. A lipoma contains mature fat, not zonal bone formation.
D. Malignant osteoid and cytological atypia would support osteosarcoma rather than orderly peripheral maturation.
- Early lesions can be difficult to distinguish from malignancy.
- Interpret biopsy with imaging and the lesion evolution.
- Early central sampling of myositis ossificans may be misleading without the zonal context.
Q135. An extra-axial dural-based tumour shows meningothelial whorls and psammoma bodies. Which diagnosis is most likely?
Appeared in (recall papers): 2022 or 2023 (session not specified); September 2024
A. Meningioma
B. Glioblastoma
C. Pituitary adenoma
D. Schwannoma
Answer and explanation
A. Meningioma
The dural relationship and meningothelial pattern support meningioma. A dural tail is suggestive but not independently diagnostic.
B. This is an infiltrating intra-axial glial malignancy.
C. This is a pituitary neuroendocrine tumour in the sellar region.
D. This has Schwann-cell differentiation and typically Antoni A/B patterns.
- A dural tail is suggestive but not independently diagnostic.
- Grade and molecular features influence behaviour.
- Meningiomas arise from meningothelial cells associated with the arachnoid.
Q136. Which stain is a sensitive marker used within an immunohistochemical panel for melanocytic differentiation, while lacking specificity for melanoma?
Appeared in (recall papers): September 2017; September 2018
A. Prostate-specific antigen
B. S100
C. Thyroglobulin
D. Alpha-fetoprotein
Answer and explanation
B. S100
S100 is sensitive but also stains other cell types and tumours. Use a panel such as SOX10 and melanocytic markers with morphology.
A. PSA supports prostatic differentiation.
C. Thyroglobulin supports thyroid follicular-cell differentiation.
D. AFP supports selected germ-cell or hepatocellular differentiation.
- Use a panel such as SOX10 and melanocytic markers with morphology.
- An IHC marker is different from a serum screening test.
- S100 also stains neural and other non-melanocytic tissues.
Q137. Which serum marker may be used as an adjunct when monitoring selected patients with metastatic breast cancer, rather than as a standalone screening or diagnostic test?
Appeared in (recall papers): September 2017; January 2021
A. CA 15-3
B. PSA
C. AFP
D. Calcitonin
Answer and explanation
A. CA 15-3
CA 15-3 may contribute to monitoring in the appropriate metastatic setting. Marker trends require clinical and imaging correlation.
B. PSA is associated with prostate tissue.
C. AFP is associated with selected liver and germ-cell tumours.
D. Calcitonin is characteristic of medullary thyroid carcinoma.
- Marker trends require clinical and imaging correlation.
- A normal CA 15-3 does not exclude breast cancer.
- CA 15-3 is not a population screening test for breast cancer.
Q138. In a normal somatic cell with intact checkpoints, critically shortened telomeres can trigger which response?
Appeared in (recall papers): 2022 or 2023 (session not specified); January 2023
A. Unlimited proliferation in every cell
B. Immediate class switching to IgE
C. Stable cell-cycle arrest, or replicative senescence
D. Obligatory epithelial metaplasia
Answer and explanation
C. Stable cell-cycle arrest, or replicative senescence
Telomere dysfunction can activate checkpoints and limit further cell division. Senescence is distinct from apoptosis.
A. Unlimited division requires escape from protective mechanisms.
B. Antibody class switching is unrelated to telomere-triggered arrest.
D. Telomere shortening does not obligatorily cause a mature epithelial cell-type switch.
- Senescence is distinct from apoptosis.
- Cancer cells may escape limits by maintaining telomeres.
- Senescent cells remain metabolically active despite stable proliferation arrest.
Q139. Which change can help a cancer cell maintain telomeres and continue dividing?
Appeared in (recall papers): 2022 or 2023 (session not specified); January 2023
A. Telomerase reactivation
B. Permanent loss of all DNA synthesis
C. Progressive telomere loss with fully intact checkpoints
D. Conversion of fibrin to fibrinogen
Answer and explanation
A. Telomerase reactivation
Telomerase can maintain telomeric DNA and support replicative immortality. Some cancers use alternative telomere-lengthening mechanisms.
B. A cell unable to replicate DNA cannot continue dividing.
C. This tends to limit division rather than sustain it.
D. This is unrelated to telomere maintenance.
- Some cancers use alternative telomere-lengthening mechanisms.
- Telomerase activation and senescence are different biological concepts.
- Telomere maintenance permits proliferation but is not the only change needed for cancer.
Q140. A testicular germ-cell tumour contains teratoma. Which statement about AFP and beta-hCG is most accurate?
Appeared in (recall papers): January 2016
A. AFP is invariably raised in a pure teratoma
B. Beta-hCG uniquely proves a teratomatous component
C. Normal markers exclude all germ-cell malignancy
D. A pure teratoma does not characteristically secrete either marker; elevation suggests another component
Answer and explanation
D. A pure teratoma does not characteristically secrete either marker; elevation suggests another component
Mixed germ-cell tumours can contain marker-producing components such as yolk sac tumour or choriocarcinoma. Marker pattern and histology must be interpreted together.
A. This is incorrect; pure teratoma may have normal markers.
B. Beta-hCG does not specifically identify teratoma.
C. Marker-negative malignant tumours can occur.
- Marker pattern and histology must be interpreted together.
- The historical broad use of testicular teratoma should not be confused with a pure teratoma component.
- Raised AFP argues against a diagnosis of pure seminoma.
Q141. A lung tumour is associated with euvolaemic hypotonic hyponatraemia and inappropriately concentrated urine. Which histological type has the classic ectopic-ADH association?
Appeared in (recall papers): January 2020; January 2025
A. Squamous cell carcinoma as the characteristic PTHrP tumour
B. Small-cell lung carcinoma
C. Pleural mesothelioma
D. Pulmonary hamartoma
Answer and explanation
B. Small-cell lung carcinoma
SCLC is classically associated with SIADH. Exclude other causes of hyponatraemia and establish SIADH criteria.
A. Squamous carcinoma is more classically linked to PTHrP-mediated hypercalcaemia.
C. This is not the classic ectopic-ADH association.
D. This benign lesion does not characteristically cause SIADH.
- Exclude other causes of hyponatraemia and establish SIADH criteria.
- Not every patient with SCLC develops SIADH.
- Ectopic ADH promotes water retention and dilutional hyponatraemia.
Q142. A patient with lung squamous carcinoma has hypercalcaemia and suppressed endogenous PTH. Which mediator best explains humoral hypercalcaemia?
Appeared in (recall papers): 2022 or 2023 (session not specified); May 2024
A. PTH-related peptide
B. Native parathyroid hormone
C. Calcitriol
D. Calcitonin
Answer and explanation
A. PTH-related peptide
PTHrP can activate PTH receptors and cause humoral hypercalcaemia of malignancy. PTH and PTHrP are different molecules.
B. The suppressed endogenous PTH argues against PTH-driven primary hyperparathyroidism.
C. Calcitriol-mediated hypercalcaemia is more characteristically associated with lymphoma and granulomatous disease.
D. Calcitonin does not explain the characteristic PTHrP-mediated hypercalcaemia of lung SCC.
- PTH and PTHrP are different molecules.
- Malignancy can also cause hypercalcaemia through bone destruction or other mechanisms.
- An appropriately low native PTH supports a PTH-independent hypercalcaemic mechanism.
Q143. A young adult has an anterior mediastinal germ-cell tumour and a substantially elevated AFP. Which classification is favoured?
Appeared in (recall papers): January 2025
A. Pure seminoma
B. Simple bronchogenic cyst
C. Thymoma as the marker-producing diagnosis
D. Nonseminomatous germ-cell tumour
Answer and explanation
D. Nonseminomatous germ-cell tumour
Raised AFP supports a nonseminomatous component such as yolk sac differentiation. Assess for a gonadal primary and mixed histology.
A. A pure seminoma does not produce AFP.
B. A benign cyst does not explain this germ-cell marker pattern.
C. AFP is not the characteristic thymoma marker.
- Assess for a gonadal primary and mixed histology.
- A marker result supports classification but does not replace tissue and imaging assessment.
- The anterior mediastinum is a recognised extragonadal germ-cell tumour site.
Q144. A colorectal adenoma has crowded atypical glands, elongated hyperchromatic nuclei and loss of normal maturation, without submucosal invasion. What process is demonstrated?
Appeared in (recall papers): May 2024
A. Proven submucosal carcinoma
B. Atrophy
C. Simple metaplasia alone
D. Epithelial dysplasia
Answer and explanation
D. Epithelial dysplasia
The cytological and architectural atypia support dysplasia. An adenoma is a neoplastic polyp.
A. The stem specifically excludes submucosal invasion.
B. Atrophy reduces tissue mass rather than producing crowded atypical glands.
C. Metaplasia describes a change in mature cell type, not this atypical glandular pattern.
- An adenoma is a neoplastic polyp.
- Grade dysplasia separately from the depth of invasion.
- Dysplasia severity and invasive depth are assessed separately.
Q145. An older adult has a slowly enlarging pearly facial nodule with telangiectasia and a rolled ulcerated edge. Biopsy shows basaloid nests with peripheral palisading. What is most likely?
Appeared in (recall papers): January 2020; September 2020; May 2024
A. Keratoacanthoma
B. Basal cell carcinoma
C. Seborrhoeic keratosis
D. Melanoma
Answer and explanation
B. Basal cell carcinoma
The clinical and microscopic pattern supports BCC. BCC can be locally destructive.
A. This classically has rapid crateriform growth with a central keratin plug.
C. This is a benign keratinocytic lesion rather than invasive basaloid tumour nests.
D. Melanoma has melanocytic differentiation and a different histological pattern.
- BCC can be locally destructive.
- Histological subtype, site and margin status influence management.
- Peripheral palisading refers to alignment of nuclei at the edge of basaloid tumour nests.
Q146. A patient with small-cell lung carcinoma develops proximal weakness and depressed reflexes that improve transiently after exercise. Which antibody target is characteristic?
Appeared in (recall papers): January 2025
A. Presynaptic voltage-gated calcium channels
B. Postsynaptic acetylcholine receptors
C. Intrinsic factor
D. Thyroid peroxidase
Answer and explanation
A. Presynaptic voltage-gated calcium channels
Reduced presynaptic calcium entry impairs acetylcholine release in Lambert–Eaton syndrome. Autonomic symptoms may accompany Lambert–Eaton syndrome.
B. This is the classic target in myasthenia gravis.
C. This is associated with pernicious anaemia.
D. This is associated with autoimmune thyroid disease.
- Autonomic symptoms may accompany Lambert–Eaton syndrome.
- The presynaptic mechanism differs from myasthenia gravis.
- Improvement after brief muscle activity is a useful Lambert–Eaton clue.
Q147. A well-circumscribed lung nodule contains disorganised mature cartilage, fat and connective tissue with entrapped respiratory epithelium. Which diagnosis is most likely?
Appeared in (recall papers): April 2025; Paper/session not recorded in source
A. Small-cell carcinoma
B. Metastatic osteosarcoma
C. Mesothelioma
D. Pulmonary hamartoma
Answer and explanation
D. Pulmonary hamartoma
The lesion contains a disorganised mixture of mature tissues normally found in the region. A hamartoma is not simply any mixture of embryonic germ-layer tissues.
A. This is a malignant small-cell neuroendocrine tumour.
B. This would require malignant osteoid-producing cells.
C. Mesothelioma arises from pleural mesothelial tissue rather than this mixed benign parenchymal pattern.
- A hamartoma is not simply any mixture of embryonic germ-layer tissues.
- Imaging may show fat or popcorn-type calcification.
- A pulmonary hamartoma is a benign lesion, although a lung nodule still needs appropriate assessment.
Q148. A changing pigmented nail-unit lesion is biopsied and shows invasive malignant melanocytes. An ipsilateral inguinal node contains the same tumour. What does the nodal finding represent?
Appeared in (recall papers): January 2017; January 2018; January 2020
A. Basal cell carcinoma by definition
B. Regional metastatic melanoma
C. A separate primary lymphoma
D. A benign naevus without need for comparison
Answer and explanation
B. Regional metastatic melanoma
Matching malignant melanocytes in the draining regional node establish nodal spread. A suspicious nail lesion needs assessment; pigmentation alone does not establish melanoma.
A. BCC has basaloid epithelial differentiation, not malignant melanocytes.
C. The node contains the same melanocytic tumour, not a lymphoid malignancy.
D. The stem explicitly describes matching invasive malignant tumour.
- A suspicious nail lesion needs assessment; pigmentation alone does not establish melanoma.
- Regional nodes affect staging and prognosis.
- A melanoma deposit in a regional node is different from distant visceral metastasis.
Q149. When assessing a melanoma confined to the skin with no nodal or distant disease, which measurement is central to primary-tumour microstaging?
Appeared in (recall papers): January 2017; September 2017; January 2018; September 2018; January 2019; January 2020; September 2022; May 2023; January 2024; September 2024; April 2025
A. Mitotic rate
B. Breslow thickness
C. Clark level
D. Surface diameter
Answer and explanation
B. Breslow thickness
Vertical tumour thickness is a central component of primary melanoma microstaging. Overall prognosis also depends on ulceration, nodes and distant metastases.
A. Mitotic activity provides prognostic information but is not the same measurement as tumour thickness.
C. Clark level describes anatomical level of invasion and has been superseded by thickness for routine T classification.
D. Diameter may affect clinical suspicion but is not the vertical microstaging measurement.
- Overall prognosis also depends on ulceration, nodes and distant metastases.
- Do not claim thickness outweighs distant metastasis when comparing all disease stages.
- Ulceration is another important component of primary melanoma staging.
Q150. An older adult has several well-demarcated waxy stuck-on brown plaques. Histology shows a benign keratinocytic proliferation with horn cysts. What is most likely?
Appeared in (recall papers): January 2021
A. Melanoma
B. Actinic keratosis
C. Seborrhoeic keratosis
D. Basal cell carcinoma
Answer and explanation
C. Seborrhoeic keratosis
Stuck-on plaques and horn cysts support this benign lesion. Pigmentation alone cannot distinguish a benign lesion from melanoma.
A. Melanoma contains a malignant melanocytic proliferation.
B. Actinic keratosis shows atypical keratinocytes related to sun damage rather than the specified benign horn-cyst pattern.
D. BCC shows basaloid nests and peripheral palisading.
- Pigmentation alone cannot distinguish a benign lesion from melanoma.
- A changing or atypical lesion may still require biopsy.
- Seborrhoeic keratoses are common benign lesions in older adults.
Q151. A sun-exposed facial nodule grows rapidly over several weeks and forms a crater containing a central keratin plug. Which lesion is classically suggested?
Appeared in (recall papers): Paper/session not recorded in source
A. Actinic keratosis
B. Nodular basal cell carcinoma
C. Keratoacanthoma
D. Epidermoid cyst
Answer and explanation
C. Keratoacanthoma
A rapidly growing crateriform nodule with a central keratin plug is the classic clinical pattern. Keratoacanthoma overlaps clinically and histologically with squamous carcinoma.
A. This usually presents as a rough scaly patch rather than the classic large keratin-filled crater.
B. BCC more typically has a slowly enlarging pearly edge and telangiectasia.
D. A cyst may have a punctum and keratin contents but lacks the characteristic eruptive crateriform tumour pattern.
- Keratoacanthoma overlaps clinically and histologically with squamous carcinoma.
- Do not assume a suspicious rapidly growing lesion can safely be observed without assessment.
- A central keratin plug is suggestive but does not independently exclude invasive SCC.
Q152. Which finding is not one of the four classic SIRS criteria?
Appeared in (recall papers): September 2016
A. Temperature above 38°C or below 36°C
B. Respiratory rate above 20/min or PaCO₂ below 32 mmHg
C. Hypotension
D. Heart rate above 90/min
Answer and explanation
C. Hypotension
Blood pressure is clinically important but is not one of the classic SIRS criteria. The other classic criterion is an abnormal white-cell count or increased immature forms.
A. Temperature abnormality is a classic criterion.
B. This respiratory abnormality is a classic criterion.
D. Tachycardia is a classic criterion.
- The other classic criterion is an abnormal white-cell count or increased immature forms.
- SIRS is not synonymous with sepsis under the Sepsis-3 definition.
- Sepsis-3 requires life-threatening organ dysfunction caused by a dysregulated response to infection.
Q153. A child with severe protein malnutrition develops hepatomegaly. Which intracellular deposit commonly contributes?
Appeared in (recall papers): September 2019; September 2020
A. Triglyceride in hepatocytes
B. Ferric iron alone
C. Melanin
D. Amyloid as the usual cause
Answer and explanation
A. Triglyceride in hepatocytes
Impaired lipid handling and lipoprotein export can produce hepatic steatosis. Steatosis is accumulation of lipid within cells.
B. Iron deposition is not the defining malnutrition-associated change.
C. Melanin is not the typical deposit causing kwashiorkor hepatomegaly.
D. Amyloid is extracellular and not the usual explanation.
- Steatosis is accumulation of lipid within cells.
- Protein malnutrition can impair synthesis of transport and structural proteins.
- Fat accumulation can enlarge the liver without proving primary hepatic malignancy.
Q154. After prolonged strenuous exertion, a patient has severe muscle pain, markedly raised creatine kinase and dark urine with a positive haem dipstick but few red cells. Which pigment can contribute to tubular injury?
Appeared in (recall papers): September 2020
A. Stercobilin
B. Unconjugated bilirubin
C. Thyroglobulin
D. Myoglobin
Answer and explanation
D. Myoglobin
Muscle breakdown releases myoglobin, which can contribute to AKI, particularly with hypovolaemia. A haem-positive dipstick detects pigment and is not specific for intact red cells.
A. Stercobilin is a stool pigment.
B. This is albumin-bound and does not explain the exertional pigmenturia pattern.
C. Thyroglobulin is a thyroid protein rather than the muscle pigment.
- A haem-positive dipstick detects pigment and is not specific for intact red cells.
- Assess potassium and renal function because complications can be urgent.
- Creatine kinase assesses muscle injury; myoglobin is the pigment released from damaged muscle.
Q155. A man has gradual unilateral scrotal pain, epididymal tenderness and dysuria. Which diagnosis is most likely?
Appeared in (recall papers): September 2020
A. Acute epididymitis
B. Epididymal cyst
C. Simple hydrocele
D. Testicular teratoma
Answer and explanation
A. Acute epididymitis
Urinary symptoms with epididymal pain and tenderness support infection or inflammation of the epididymis. Sudden severe scrotal pain requires urgent exclusion of torsion.
B. An uncomplicated cyst is generally non-inflammatory.
C. A hydrocele is usually a fluid swelling and does not explain this inflammatory urinary pattern.
D. A tumour more commonly presents as a testicular mass rather than this urinary-inflammatory syndrome.
- Sudden severe scrotal pain requires urgent exclusion of torsion.
- Age, sexual history and urinary pathology influence likely pathogens.
- Epididymitis and testicular torsion require different urgent pathways.
Q156. A CT head shows a crescent-shaped extra-axial blood collection that can extend across cranial sutures. Which compartment is involved?
Appeared in (recall papers): January 2026
A. Ventricular system
B. Subdural space
C. Subarachnoid space
D. Extradural space
Answer and explanation
B. Subdural space
Subdural blood typically forms a crescentic collection. Bridging vein injury is a common mechanism.
A. Intraventricular blood lies within the ventricular cavities.
C. Subarachnoid blood follows sulci and cisterns rather than forming this typical crescent.
D. Extradural haematomas are typically lentiform and limited by sutures.
- Bridging vein injury is a common mechanism.
- Shape alone does not establish whether a collection is acute or chronic.
- An extradural collection is classically biconvex rather than crescentic.
Q157. After persistent middle-ear infection, a patient develops fever, gait ataxia and ipsilateral dysmetria. Imaging identifies a ring-enhancing cerebellar lesion with restricted diffusion. What is most likely?
Appeared in (recall papers): January 2021
A. Stable meningioma
B. Subarachnoid haemorrhage
C. Uncomplicated benign positional vertigo
D. Cerebellar abscess
Answer and explanation
D. Cerebellar abscess
Otogenic infection can spread to the posterior fossa and produce a suppurative lesion. A focal posterior fossa lesion may cause obstructive hydrocephalus.
A. This does not explain the infective course and restricted-diffusion abscess pattern.
B. This produces a different imaging pattern rather than a pus-containing focal lesion.
C. This does not cause fever and a focal ring-enhancing lesion.
- A focal posterior fossa lesion may cause obstructive hydrocephalus.
- Do not perform lumbar puncture before assessing mass effect in this setting.
- An otogenic abscess may also involve the temporal lobe.
Q158. In complete biliary obstruction, what chiefly explains bulky greasy stools that are difficult to flush?
Appeared in (recall papers): January 2018; January 2021
A. Reduced intestinal bile salts impair fat absorption
B. Increased stercobilin
C. Increased urinary conjugated bilirubin
D. Increased urinary urea
Answer and explanation
A. Reduced intestinal bile salts impair fat absorption
Bile salts are needed for effective micellar solubilisation and absorption of dietary fat. Loss of stool pigment and loss of fat absorption are different effects.
B. Less bile pigment reaches the bowel; increased stercobilin would not explain the obstruction pattern.
C. This explains bilirubin-positive dark urine, not fat malabsorption.
D. This does not provide the mechanism of steatorrhoea.
- Loss of stool pigment and loss of fat absorption are different effects.
- Reduced stercobilin delivery contributes to pale stool colour.
- Bile pigments provide stool colour, whereas bile salts aid micellar fat absorption.
Q159. Clear nasal fluid after cranial trauma requires testing for a CSF leak. Which laboratory test is particularly useful on the fluid?
Appeared in (recall papers): May 2023
A. Beta-2 transferrin
B. Urine bilirubin
C. Serum total cholesterol alone
D. Faecal elastase
Answer and explanation
A. Beta-2 transferrin
This transferrin isoform is a useful marker in the assessment of a suspected cranial CSF leak. Beta-trace protein is another marker used in some settings.
B. This tests a different fluid and pathway.
C. This does not identify CSF in a nasal sample.
D. This assesses pancreatic exocrine function rather than a CSF leak.
- Beta-trace protein is another marker used in some settings.
- Interpret results with sample quality, examination and imaging.
- Nasal-fluid glucose testing is insufficiently reliable to replace a specific CSF marker test.
Q160. An otherwise healthy boy develops a small soft subareolar breast disc during puberty, without a testicular mass or other abnormal examination findings. What is the most likely explanation?
Appeared in (recall papers): January 2024
A. Breast carcinoma as the usual diagnosis
B. Mumps infection as the direct usual cause
C. Pituitary carcinoma as the usual cause
D. Physiological pubertal gynaecomastia
Answer and explanation
D. Physiological pubertal gynaecomastia
A transient relative hormonal imbalance can cause benign pubertal breast enlargement. Pubertal gynaecomastia may be unilateral or asymmetrical.
A. Cancer is very uncommon in this setting and is not the usual cause.
B. Mumps does not ordinarily produce isolated physiological subareolar tissue.
C. This is not the common explanation for an otherwise normal pubertal examination.
- Pubertal gynaecomastia may be unilateral or asymmetrical.
- Rapid progression, a hard eccentric mass or endocrine abnormalities require assessment.
- True gynaecomastia is glandular subareolar tissue, distinct from adipose enlargement alone.
Q161. Which plasma protein is a negative acute-phase reactant and may decrease during systemic inflammation?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Serum amyloid A
B. C-reactive protein
C. Albumin
D. Fibrinogen
Answer and explanation
C. Albumin
Albumin is a negative acute-phase protein, although several mechanisms affect its concentration. Inflammation can alter albumin independently of nutritional intake.
A. SAA is a positive acute-phase reactant.
B. CRP is a positive acute-phase reactant.
D. Fibrinogen generally rises during an acute-phase response.
- Inflammation can alter albumin independently of nutritional intake.
- CRP and fibrinogen are both positive acute-phase reactants.
- Albumin concentration is affected by inflammation, synthesis, distribution and losses.
Q162. A patient with acute pancreatitis has corrected calcium 3.30 mmol/L, triglycerides 1.6 mmol/L and no identified biliary cause. Which endocrine cause should be investigated?
Appeared in (recall papers): May 2022; Paper/session not recorded in source
A. Primary hypothyroidism as the characteristic cause
B. Primary hyperparathyroidism
C. Isolated adrenal medullary hypofunction
D. Diabetes insipidus as a proven diagnosis
Answer and explanation
B. Primary hyperparathyroidism
Marked hypercalcaemia warrants PTH assessment; primary hyperparathyroidism is a possible PTH-dependent cause. A raised calcium alone does not prove primary hyperparathyroidism.
A. This is not the characteristic endocrine explanation for marked hypercalcaemia.
C. This is not the typical explanation for this calcium pattern.
D. Polyuria and water-balance findings would be required, and it does not establish the cause of hypercalcaemia.
- A raised calcium alone does not prove primary hyperparathyroidism.
- Measure PTH to distinguish PTH-dependent from PTH-independent hypercalcaemia.
- Hypercalcaemia in pancreatitis warrants a search for an underlying cause rather than assumption of one.
Q163. Chronic Schistosoma haematobium infection is particularly associated with which bladder malignancy?
Appeared in (recall papers): April 2026
A. Prostatic acinar adenocarcinoma
B. Squamous cell carcinoma
C. Clear-cell renal cell carcinoma
D. Wilms tumour
Answer and explanation
B. Squamous cell carcinoma
Chronic irritation and squamous metaplastic change increase SCC risk in endemic settings. Metaplasia is an adaptive change; carcinoma requires malignant transformation.
A. This originates in the prostate.
C. RCC arises in renal parenchyma rather than as this characteristic bladder association.
D. This is a childhood renal tumour.
- Metaplasia is an adaptive change; carcinoma requires malignant transformation.
- Urothelial carcinoma remains important in the overall differential of haematuria.
- Schistosomal carcinogenesis involves longstanding bladder inflammation.
Q164. Among classic Hodgkin histological subtypes, which has traditionally been associated with a relatively adverse clinical course?
Appeared in (recall papers): January 2021
A. Lymphocyte-depleted classic Hodgkin lymphoma
B. Lymphocyte-rich classic Hodgkin lymphoma
C. Nodular sclerosis as invariably the worst
D. All subtypes have identical stage-independent outcomes
Answer and explanation
A. Lymphocyte-depleted classic Hodgkin lymphoma
This rare subtype is often associated with adverse clinical presentations. Modern prognosis depends strongly on stage, risk features and treatment response.
B. This generally has a more favourable association than the lymphocyte-depleted subtype.
C. Nodular sclerosis is common and is not uniformly the worst subtype.
D. Clinical stage and other risk factors matter, so outcomes cannot be assumed identical.
- Modern prognosis depends strongly on stage, risk features and treatment response.
- Do not use histological subtype alone to predict an individual outcome.
- The subtype name describes the paucity of background lymphocytes relative to malignant cells.
Q165. A squamous epithelial biopsy shows full-thickness malignant cytological atypia with an intact basement membrane and no stromal invasion. What is the best description?
Appeared in (recall papers): May 2022; 2022 or 2023 (session not specified); September 2024
A. Simple metaplasia
B. Squamous carcinoma in situ
C. Benign hyperplasia
D. Invasive squamous carcinoma
Answer and explanation
B. Squamous carcinoma in situ
Full-thickness severe atypia without invasion supports carcinoma in situ. Partial-thickness atypia is not automatically carcinoma in situ.
A. Metaplasia alone does not imply full-thickness malignant atypia.
C. Hyperplasia does not explain the malignant cytological features.
D. Invasive carcinoma requires basement membrane breach.
- Partial-thickness atypia is not automatically carcinoma in situ.
- The basement membrane separates in situ from invasive disease.
- In situ is a statement about confinement, whereas differentiation describes how tumour cells resemble their parent tissue.
Q166. A man with chronic pancreatitis has persistent steatorrhoea. Which of the following is the most appropriate initial test for pancreatic exocrine insufficiency?
Appeared in (recall papers): May 2024
A. Serum lipase
B. Serum amylase
C. Faecal elastase on a formed stool sample
D. Serum alkaline phosphatase
Answer and explanation
C. Faecal elastase on a formed stool sample
Faecal elastase is the recommended initial test for suspected pancreatic exocrine insufficiency. Use a semi-solid or solid stool specimen; watery stool may dilute elastase and produce a falsely low result.
A. Serum lipase is used mainly in acute pancreatic injury and does not reliably quantify chronic exocrine insufficiency.
B. Serum amylase may be normal in chronic pancreatic disease and is not the preferred initial exocrine function test.
D. ALP assesses a cholestatic or bone pattern rather than pancreatic digestive enzyme output.
- Use a semi-solid or solid stool specimen; watery stool may dilute elastase and produce a falsely low result.
- A faecal elastase below 100 micrograms/g supports exocrine insufficiency; 100–200 micrograms/g is indeterminate.
- Faecal elastase can be measured while the patient is taking pancreatic enzyme replacement therapy.
Q167. A woman has a woody hard thyroid swelling with dysphagia and hoarseness. Biopsy shows dense fibrosis extending beyond the thyroid capsule, without malignant cells. What is the most likely diagnosis?
Appeared in (recall papers): May 2024
A. Medullary thyroid carcinoma
B. Anaplastic thyroid carcinoma
C. Riedel thyroiditis
D. Papillary thyroid carcinoma
Answer and explanation
C. Riedel thyroiditis
Riedel thyroiditis is a fibrosing inflammatory disorder that may extend into adjacent tissues and cause compressive symptoms. Extrathyroidal fibrosis helps distinguish Riedel disease from the fibrosing variant of Hashimoto thyroiditis.
A. Medullary carcinoma is a C-cell tumour, often with calcitonin expression and stromal amyloid.
B. Anaplastic carcinoma may cause a hard invasive mass, but biopsy would show a malignant undifferentiated tumour.
D. Papillary carcinoma has characteristic malignant nuclear features rather than isolated extensive benign fibrosis.
- Extrathyroidal fibrosis helps distinguish Riedel disease from the fibrosing variant of Hashimoto thyroiditis.
- Riedel thyroiditis may be associated with IgG4-related disease and fibrosis elsewhere.
- Hypothyroidism may accompany the fibrosing goitre; a woody mass still requires exclusion of malignancy.
Q168. An older man has cardiac amyloidosis. Amyloid typing identifies wild-type ATTR. Which protein is the precursor of these deposits?
Appeared in (recall papers): May 2024
A. Immunoglobulin light chains
B. Beta-2 microglobulin
C. Serum amyloid A
D. Transthyretin
Answer and explanation
D. Transthyretin
ATTR fibrils are derived from transthyretin; the wild-type form can cause age-associated cardiac amyloidosis. Both variant and wild-type transthyretin can form amyloid; family history alone does not type the deposits.
A. Immunoglobulin light chains form AL amyloid, not ATTR.
B. Beta-2 microglobulin amyloid is associated particularly with long-term dialysis.
C. Serum amyloid A is the precursor of AA amyloid associated with sustained inflammation.
- Both variant and wild-type transthyretin can form amyloid; family history alone does not type the deposits.
- Cardiac amyloidosis can be AL or ATTR, so clinical suspicion requires an appropriate typing pathway.
- Congo red with apple-green birefringence establishes amyloid deposition but does not identify its precursor protein.
Q169. A dialysis patient with longstanding secondary hyperparathyroidism develops persistent hypercalcaemia and markedly raised PTH. Which diagnosis best explains the change?
Appeared in (recall papers): January 2020
A. Uncomplicated secondary hyperparathyroidism
B. Vitamin D intoxication
C. Tertiary hyperparathyroidism
D. Humoral hypercalcaemia of malignancy
Answer and explanation
C. Tertiary hyperparathyroidism
Chronically stimulated parathyroid tissue can become autonomous. PTH then remains excessive despite hypercalcaemia.
A. PTH rises as a compensatory response, usually with normal or low calcium rather than this autonomous hypercalcaemic pattern.
B. Hypercalcaemia due to vitamin D excess usually suppresses endogenous PTH.
D. PTHrP-mediated hypercalcaemia usually suppresses native PTH.
- The renal disease and previous secondary hyperparathyroidism distinguish the clinical context from typical primary disease.
- Phosphate may remain elevated when renal excretion is impaired.
- PTH must be interpreted with calcium, phosphate, renal function and the preceding clinical history.
Q170. Previously normal calf muscles become smaller after prolonged limb immobilisation. Which cellular adaptation best explains this?
Appeared in (recall papers): Paper/session not recorded in source
A. Hypoplasia
B. Metaplasia
C. Atrophy
D. Hypertrophy
Answer and explanation
C. Atrophy
Reduced loading promotes loss of cellular protein and shrinkage of muscle fibres. This is an acquired reduction in previously developed tissue.
A. Hypoplasia means incomplete development, rather than acquired wasting of previously normal muscle.
B. Metaplasia replaces one differentiated cell type with another.
D. Hypertrophy is an increase in cell size, the opposite of this change.
- Atrophy can follow disuse, denervation, poor nutrition or reduced blood supply.
- Hypoplasia and atrophy describe different developmental histories.
- Restoration of activity can improve uncomplicated disuse atrophy, but recovery depends on the underlying cause.
Q171. An anterior mediastinal tumour contains neoplastic thymic epithelial cells mixed with immature T lymphocytes. What is the diagnosis?
Appeared in (recall papers): January 2017
A. Bronchial squamous carcinoma
B. Schwannoma
C. T-lymphoblastic lymphoma
D. Thymoma
Answer and explanation
D. Thymoma
Thymoma is a thymic epithelial neoplasm with a variable population of non-neoplastic immature T cells. Recognising the epithelial tumour component distinguishes it from a purely lymphoid neoplasm.
A. This does not have the characteristic thymic epithelial and immature T-cell mixture.
B. Schwannoma is a peripheral nerve-sheath tumour with a different architecture.
C. This is a neoplasm of lymphoid blasts, without the described neoplastic thymic epithelial framework.
- Hassall corpuscles identify thymic differentiation but do not alone establish thymoma.
- Thymoma may be associated with myasthenia gravis.
- An anterior mediastinal mass has a broader differential that includes lymphoma and germ-cell tumours.
Q172. A woman with objectively confirmed recurrent DVT has a persistently positive lupus anticoagulant on tests 14 weeks apart. Which acquired thrombophilia is most likely?
Appeared in (recall papers): September 2018; January 2019; January 2020; September 2020; January 2021; September 2024; Paper/session not recorded in source
A. Protein C deficiency
B. Factor V Leiden
C. Antiphospholipid syndrome
D. Haemophilia A
Answer and explanation
C. Antiphospholipid syndrome
Thrombosis together with persistent antiphospholipid antibodies supports APS in the appropriate clinical setting. A lupus anticoagulant can prolong phospholipid-dependent clotting tests despite a tendency to thrombosis.
A. This inherited or acquired anticoagulant deficiency does not account for the specified antibody result.
B. This is an inherited activated-protein-C resistance disorder, not the explanation for persistent lupus anticoagulant positivity.
D. Factor VIII deficiency usually causes bleeding, not this antibody-associated thrombotic syndrome.
- Relevant tests include lupus anticoagulant, anticardiolipin and anti-beta-2-glycoprotein I antibodies.
- Persistence generally requires positive results at least 12 weeks apart; classification criteria are not a substitute for clinical diagnosis.
- Family history of pregnancy-associated thrombosis alone does not establish APS.
Q173. An acutely swollen knee contains rhomboid or rod-shaped crystals with weak positive birefringence. Which crystal is most likely?
Appeared in (recall papers): May 2023
A. Basic calcium phosphate
B. Monosodium urate
C. Cholesterol
D. Calcium pyrophosphate
Answer and explanation
D. Calcium pyrophosphate
CPP crystals characteristically show weak positive birefringence and may be rhomboid or rod-shaped. Crystal examination should be interpreted with the clinical findings.
A. These crystals are generally too small to identify by routine compensated polarised light microscopy.
B. Urate crystals are classically needle-shaped with strong negative birefringence.
C. Cholesterol crystals are usually flat plates with notched corners.
- Chondrocalcinosis supports CPP deposition but is not present in every symptomatic case.
- Crystals in an aspirate do not exclude coexisting septic arthritis.
- Weak birefringence can make CPP crystals harder to detect than strongly birefringent urate crystals.
Q174. During normal cutaneous scar maturation, which collagen increasingly replaces the early type III-rich matrix?
Appeared in (recall papers): April 2025
A. Type II collagen
B. Type IV collagen
C. Type I collagen
D. Type VII collagen
Answer and explanation
C. Type I collagen
Scar remodelling increases the proportion of type I collagen relative to the early type III-rich matrix. Fibre organisation and cross-linking also contribute to increasing strength.
A. Type II is characteristic of hyaline cartilage rather than the dominant mature skin scar collagen.
B. Type IV forms basement-membrane networks rather than the main fibrillar scar matrix.
D. Type VII forms anchoring fibrils at epithelial basement-membrane zones.
- A keloid contains abnormal collagen architecture and should not be reduced to one universally exclusive collagen type.
- Scar remodelling continues after the wound has epithelialised.
- Skin scars do not recover all the mechanical properties of uninjured skin.
Q175. Which tissue characterises the soft-callus phase of secondary fracture healing?
Appeared in (recall papers): April 2025
A. Mineralised woven-bone hard callus
B. Mature organised lamellar bone
C. Fresh haematoma without a tissue bridge
D. Fibrocartilaginous tissue bridging the fracture
Answer and explanation
D. Fibrocartilaginous tissue bridging the fracture
Soft callus forms a provisional fibrocartilaginous bridge. It is subsequently replaced by mineralised tissue as healing progresses.
A. This is the subsequent hard-callus stage rather than the soft provisional bridge.
B. Lamellar remodelling is a later process and does not define soft callus.
C. A haematoma is an earlier response and is not the fibrocartilaginous soft callus itself.
- Secondary healing occurs under relative stability; direct healing requires a sufficiently stable mechanical environment.
- The timing of a healing phase varies with site, biology and fixation, so three weeks is not a universal histological cutoff.
- Both endochondral and intramembranous bone formation contribute to secondary fracture repair.
Q176. A preterm neonate develops abdominal distension, bloody stools and pneumatosis intestinalis. What is the most likely diagnosis?
Appeared in (recall papers): January 2026
A. Uncomplicated gastro-oesophageal reflux
B. Necrotising enterocolitis
C. Meconium ileus
D. Infantile hypertrophic pyloric stenosis
Answer and explanation
B. Necrotising enterocolitis
NEC causes inflammatory injury and necrosis of neonatal intestine, particularly in premature infants. Intramural bowel gas supports the diagnosis in this clinical setting.
A. Reflux does not explain this bowel-wall gas and systemic intestinal illness.
C. This is obstruction from inspissated meconium and has a different characteristic presentation.
D. This typically causes non-bilious vomiting and does not explain bloody stool with pneumatosis.
- Pneumatosis intestinalis means gas within the bowel wall.
- Pneumoperitoneum indicates perforation and requires urgent surgical assessment.
- NEC can progress to bowel necrosis, perforation and systemic deterioration.
Q177. A euvolaemic patient with longstanding diabetes has a sustained postural blood-pressure fall and little compensatory tachycardia. Which complication best explains this?
Appeared in (recall papers): January 2026
A. Isolated diabetic retinopathy
B. Autonomic neuropathy
C. Isolated distal sensory neuropathy
D. Hyperthyroidism
Answer and explanation
B. Autonomic neuropathy
Damage to autonomic nerves can impair the cardiovascular response to standing. In diabetes, this can produce orthostatic hypotension with an inadequate heart-rate response.
A. Retinal microvascular damage does not directly explain the specified blood-pressure response.
C. Sensory loss alone does not explain impaired autonomic cardiovascular compensation.
D. This usually increases adrenergic cardiovascular activity and does not best fit this pattern.
- Exclude volume depletion and medication effects before attributing postural symptoms to neuropathy.
- Diabetic autonomic neuropathy may also affect gastric emptying and bladder function.
- Autonomic and distal peripheral sensory neuropathy may coexist but describe different affected functions.
Q178. What destructive tissue invades cartilage and bone in rheumatoid arthritis?
Appeared in (recall papers): January 2021; May 2022; September 2024
A. Inflamed proliferative synovial pannus
B. Marginal osteophyte
C. Urate tophus
D. Subcutaneous rheumatoid nodule
Answer and explanation
A. Inflamed proliferative synovial pannus
Chronically inflamed synovium becomes a proliferative tissue that invades adjacent cartilage and bone. This is distinct from the necrobiotic structure of a subcutaneous rheumatoid nodule.
B. An osteophyte is a bony outgrowth characteristic of degenerative joint disease rather than invasive inflammatory synovium.
C. Urate deposition defines gout and is not the essential rheumatoid synovial lesion.
D. A rheumatoid nodule contains central necrobiosis and palisading histiocytes; it is not the invading synovial tissue asked here.
- Rheumatoid nodules have central fibrinoid necrobiosis surrounded by palisading histiocytes.
- Osteophyte-dominant degeneration is characteristic of osteoarthritis rather than the defining rheumatoid erosive process.
- The distinction between a rheumatoid nodule and rheumatoid synovitis depends on the sampled tissue.
Q179. Which wound cell phagocytoses debris and releases mediators that coordinate fibroblast activity and angiogenesis?
Appeared in (recall papers): September 2024
A. Fibroblast
B. Neutrophil
C. Macrophage
D. Endothelial cell
Answer and explanation
C. Macrophage
Macrophages clear damaged material and provide signals that support repair. Their role extends beyond simply killing organisms.
A. Fibroblasts make extracellular matrix; they are not the principal debris-clearing phagocyte described.
B. Neutrophils are important early antimicrobial phagocytes, but the coordinated transition to fibroplasia and angiogenesis particularly highlights macrophage function.
D. Endothelial cells form new blood vessels rather than serving as the principal phagocytic coordinator.
- Neutrophils and macrophages overlap during the inflammatory phase.
- Fibroblasts synthesise extracellular matrix; endothelial cells form new vessels.
- Cell populations overlap during healing, so a calendar day alone is a poor single-cell discriminator.
Q180. A colorectal carcinoma extends through muscularis propria into pericolic tissue, with no regional nodal or distant metastases. What is its Dukes stage?
Appeared in (recall papers): September 2017; Paper/session not recorded in source
A. Dukes A
B. Dukes B
C. Dukes C
D. Dukes D
Answer and explanation
B. Dukes B
Dukes B describes extension through the bowel muscle without regional nodal involvement. The corresponding broad modern stage group is stage II when distant metastases are absent.
A. Dukes A is confined to the bowel wall rather than the specified extramural extension.
C. Dukes C requires regional lymph-node involvement.
D. Dukes D denotes distant metastatic disease.
- TNM gives more detail than the older Dukes system.
- A single historical five-year survival percentage should not be treated as universal across modern patient populations.
- Node-positive disease belongs to Dukes C even when distant metastases are absent.
Q181. Which coagulation factor is deficient in haemophilia B?
Appeared in (recall papers): September 2020
A. Factor XIII
B. Factor IX
C. Factor VII
D. Factor VIII
Answer and explanation
B. Factor IX
Haemophilia B is caused by deficient factor IX activity. It produces a deep-tissue and joint bleeding tendency similar to haemophilia A.
A. Factor XIII deficiency impairs fibrin stabilisation and may occur with normal routine PT and aPTT.
C. Factor VII deficiency primarily affects the tissue-factor pathway and typically prolongs PT.
D. Factor VIII deficiency causes haemophilia A.
- The usual inherited forms of haemophilia A and B are X-linked.
- A prolonged aPTT alone does not identify which intrinsic-pathway factor is deficient.
- A specific factor assay distinguishes factor VIII deficiency from factor IX deficiency.
Q182. A man with an F8 pathogenic variant has children with a woman who does not carry an F8 pathogenic variant. Which transmission pattern applies to his affected X chromosome?
Appeared in (recall papers): 2022 or 2023 (session not specified); April 2025
A. All sons inherit it and no daughters inherit it
B. No daughters inherit it because the mother is unaffected
C. Half of sons inherit it directly from him
D. All daughters inherit it and no sons inherit it
Answer and explanation
D. All daughters inherit it and no sons inherit it
A father gives his X chromosome to every daughter and his Y chromosome to every son. Direct father-to-son transmission of his X-linked F8 variant therefore does not occur.
A. Sons receive their father's Y chromosome, not his X chromosome.
B. Every daughter receives the father's X irrespective of the mother's carrier status.
C. The paternal X is not transmitted to sons.
- A daughter who inherits a haemophilia variant can have clinically important bleeding; carrier does not necessarily mean asymptomatic.
- A new variant or maternal carrier state can explain an affected boy without a known family history.
- Female sex alone does not exclude clinically significant haemophilia-related bleeding.
Q183. A destructive pelvic bone tumour produces malignant cartilage matrix without malignant osteoid. Which diagnosis is most likely?
Appeared in (recall papers): April 2026
A. Conventional chondrosarcoma
B. Simple bone cyst
C. Osteosarcoma
D. Ewing sarcoma
Answer and explanation
A. Conventional chondrosarcoma
Conventional chondrosarcoma is a malignant cartilage-producing tumour. The matrix and destructive growth pattern distinguish it from benign cartilage lesions in the appropriate setting.
B. A simple bone cyst does not produce malignant cartilage.
C. Osteosarcoma is defined by malignant cells directly producing osteoid.
D. Ewing sarcoma is a small-round-cell sarcoma and does not characteristically produce a cartilage matrix.
- Conventional chondrosarcoma is more typical in adults than Ewing sarcoma.
- A cartilage lesion requires assessment of imaging, symptoms and histology together.
- The matrix directly produced by malignant cells is central to distinguishing cartilage-producing from osteoid-producing sarcomas.
Q184. A firm dermal papule contains a benign fibrohistiocytic proliferation with peripheral collagen entrapment. What is the most likely diagnosis?
Appeared in (recall papers): January 2025
A. Epidermoid cyst
B. Basal cell carcinoma
C. Pyogenic granuloma
D. Dermatofibroma
Answer and explanation
D. Dermatofibroma
Dermatofibroma is a benign fibrohistiocytic dermal lesion. Entrapment of collagen at its periphery is a useful histological clue.
A. An epidermoid cyst is a keratin-filled cyst lined by squamous epithelium.
B. BCC contains malignant basaloid epithelial nests, often with peripheral palisading.
C. Pyogenic granuloma is a lobular capillary proliferation rather than a fibrohistiocytic lesion.
- An acquired growing lesion still needs clinical assessment; a previous abscess alone does not establish its diagnosis.
- Dermatofibroma and dermatofibrosarcoma protuberans are distinct lesions.
- Histology and the lesion's growth pattern matter more than the history of a healed local infection alone.
Q185. An older adult has an enlarged deformed tibia, raised bone ALP and a mosaic pattern of irregular cement lines. What is the diagnosis?
Appeared in (recall papers): January 2025
A. Osteomalacia
B. Paget disease of bone
C. Multiple myeloma
D. Conventional osteosarcoma
Answer and explanation
B. Paget disease of bone
Disordered high-turnover bone remodelling produces a mosaic architectural pattern. Affected bone can enlarge yet remain mechanically abnormal.
A. Osteomalacia is defective mineralisation with excess unmineralised osteoid, not the characteristic mosaic architecture.
C. Myeloma is a clonal plasma-cell disorder that may cause lytic lesions, without this defining Paget pattern.
D. Osteosarcoma requires malignant osteoid production.
- ALP may reflect activity, but a normal value does not exclude limited disease.
- Paget disease can cause deformity, secondary osteoarthritis and pathological fracture.
- Paget disease of bone is different from Paget disease of the nipple.
Q186. BRCA1 helps maintain genomic stability through which DNA-repair process?
Appeared in (recall papers): January 2016
A. Homologous recombination repair of double-strand breaks
B. Mismatch repair of replication errors
C. Base excision repair of small damaged bases
D. Nucleotide excision repair of UV photoproducts
Answer and explanation
A. Homologous recombination repair of double-strand breaks
BRCA1 participates in accurate repair of DNA double-strand breaks. Loss of function can promote genomic instability and cancer predisposition.
B. Mismatch repair corrects mismatched bases and small insertion/deletion errors; it is not the defining BRCA1 pathway.
C. Base excision repair removes particular damaged bases; it is distinct from BRCA1-associated homologous recombination.
D. This is a different pathway, classically implicated in xeroderma pigmentosum.
- BRCA1 and BRCA2 are tumour-suppressor genes involved in homologous recombination.
- A patient and grandmother with breast cancer do not by themselves prove a particular pathogenic variant.
- A family history can justify hereditary-risk assessment without identifying a particular gene from the history alone.
Q187. After total thyroidectomy and radioiodine treatment for papillary thyroid carcinoma, which serum marker is useful for surveillance alongside neck imaging?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Calcitonin
B. CEA as a specific papillary marker
C. Thyroglobulin
D. AFP
Answer and explanation
C. Thyroglobulin
Thyroglobulin is produced by thyroid follicular cells and can help monitor differentiated thyroid cancer after treatment. Results require interpretation with residual tissue, TSH status and thyroglobulin antibodies.
A. Calcitonin is particularly relevant to medullary thyroid carcinoma arising from C cells.
B. CEA is not the characteristic follicular-cell surveillance marker asked here.
D. AFP is associated with different tumours, including hepatocellular and certain germ-cell tumours.
- Thyroglobulin antibodies can interfere with the assay.
- This surveillance logic must not be transferred automatically to anaplastic thyroid carcinoma.
- A rising marker prompts assessment; a single measurement does not locate or prove recurrence by itself.
Q188. A smoker has a persistent irregular vocal-cord lesion. Biopsy shows invasive malignant squamous cells with keratinisation. What is the diagnosis?
Appeared in (recall papers): January 2024
A. Urothelial carcinoma
B. Benign vocal-fold nodule
C. Adenocarcinoma
D. Squamous cell carcinoma
Answer and explanation
D. Squamous cell carcinoma
Invasion by malignant squamous cells establishes squamous carcinoma. Most laryngeal malignancies have this histological type.
A. This is not the expected primary epithelial malignancy of the vocal cord.
B. A benign nodule does not show invasion by malignant squamous cells.
C. Adenocarcinoma requires glandular differentiation rather than the specified squamous morphology.
- Persistent hoarseness can be an early clue to a glottic lesion.
- A vocal-cord nodule alone does not establish malignancy.
- Keratinisation supports squamous differentiation; stromal invasion distinguishes invasive carcinoma from an in situ lesion.
Q189. A tiny rectal polyp has serration in the upper crypts, straight narrow crypt bases and no cytological dysplasia. Which diagnosis best fits?
Appeared in (recall papers): January 2021
A. Sessile serrated lesion
B. Invasive adenocarcinoma
C. Hyperplastic polyp
D. Conventional tubular adenoma
Answer and explanation
C. Hyperplastic polyp
This architecture supports a hyperplastic polyp. Distinguishing its crypt bases from those of a sessile serrated lesion is important.
A. A sessile serrated lesion characteristically has abnormal basal crypt architecture, such as dilation and horizontal growth.
B. The stem provides no invasive malignant glands or desmoplastic response.
D. A conventional adenoma shows dysplastic epithelium.
- Not all polyps are adenomas and not all serrated lesions have the same cancer risk.
- Histological classification is needed before assigning a surveillance category.
- A lack of cytological dysplasia alone does not distinguish a hyperplastic polyp from every sessile serrated lesion.
Q190. A renal graft biopsy shows microvascular inflammation and peritubular capillary C4d. Donor-specific antibodies are detected. Which mechanism best fits?
Appeared in (recall papers): January 2025
A. Active antibody-mediated rejection
B. Pure technical renal-artery thrombosis
C. Recurrent minimal-change disease
D. Isolated acute T-cell-mediated rejection
Answer and explanation
A. Active antibody-mediated rejection
The combination of microvascular injury, antibody-endothelium interaction and donor-specific antibodies supports active antibody-mediated rejection. Biopsy and clinical findings are interpreted together.
B. Mechanical thrombosis alone does not explain donor-specific antibodies with the described microvascular immune injury.
C. This does not explain the characteristic peritubular C4d and microvascular inflammatory pattern.
D. This is principally assessed through interstitial inflammation, tubulitis or arteritis, rather than the supplied antibody-associated combination alone.
- C4d is a footprint of complement activation, not a diagnosis in isolation.
- Antibody-mediated rejection can be C4d-negative when other diagnostic evidence is present.
- Technical vascular complications and immune rejection may coexist, so graft dysfunction requires a differential diagnosis.
Q191. Biopsy-proven Hodgkin lymphoma involves cervical and inguinal nodes without disseminated extranodal disease. What is its anatomical stage?
Appeared in (recall papers): April 2026
A. Stage III
B. Stage I
C. Stage II
D. Stage IV
Answer and explanation
A. Stage III
Involved nodal groups lie on both sides of the diaphragm. Nodal disease above and below the diaphragm defines stage III.
B. Stage I involves a single lymphatic site rather than both cervical and inguinal nodal regions.
C. Stage II involves nodal regions on the same side of the diaphragm.
D. Stage IV requires disseminated extranodal involvement rather than nodal distribution alone.
- Anatomical stage does not by itself establish the histological diagnosis.
- B symptoms include unexplained fever, drenching night sweats and significant unintentional weight loss.
- Weight loss as a B symptom is conventionally more than 10 percent of body weight over six months.
Q192. After a sudden severe headache, CT shows blood in the basal cisterns and cerebral sulci. Which haemorrhage compartment is involved?
Appeared in (recall papers): January 2016; April 2017; April 2019; January 2021; September 2021; Paper/session not recorded in source
A. Brain parenchyma only
B. Subarachnoid space
C. Extradural space
D. Subdural space
Answer and explanation
B. Subarachnoid space
The basal cisterns and sulci contain CSF in the subarachnoid space. Blood in this distribution therefore indicates subarachnoid haemorrhage.
A. An intraparenchymal bleed is within brain tissue rather than primarily outlining CSF cisterns and sulci.
C. An extradural collection lies outside the dura and is typically lentiform rather than distributed through cisterns.
D. A subdural collection lies between dura and arachnoid and is typically crescentic.
- Rupture of a saccular cerebral aneurysm is an important cause of spontaneous SAH.
- Sudden collapse alone does not identify the intracranial bleeding compartment.
- Subarachnoid blood lies between arachnoid and pia rather than between skull and dura.
Q193. Which finding defines a colonic crypt abscess?
Appeared in (recall papers): January 2026
A. Granulomas around an intact crypt
B. Neutrophils within a crypt lumen
C. Mature adipose tissue replacing a crypt
D. Atypical epithelial cells breaching basement membrane
Answer and explanation
B. Neutrophils within a crypt lumen
A crypt abscess is an accumulation of neutrophils in the glandular lumen. Neutrophilic infiltration of crypt epithelium itself is termed cryptitis.
A. A granuloma is an organised macrophage collection rather than a neutrophilic luminal abscess.
C. Fat replacement is not the defining inflammatory lesion.
D. This describes invasion by carcinoma rather than a crypt abscess.
- Crypt abscesses can occur in active ulcerative colitis but are not specific to it.
- Distribution, architectural changes and clinical findings help distinguish IBD from other colitides.
- A crypt abscess is a microscopic glandular lesion and is not synonymous with a macroscopic abdominal abscess.
Q194. A smoker with haematuria has a papillary malignant urothelial tumour centred in the renal pelvis. Which diagnosis best fits?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Nephroblastoma
B. Renal angiomyolipoma
C. Clear-cell renal cell carcinoma
D. Upper-tract urothelial carcinoma
Answer and explanation
D. Upper-tract urothelial carcinoma
The renal pelvis is lined by urothelium, from which this tumour arises. It is distinct from renal cell carcinoma arising in renal parenchyma.
A. Wilms tumour is an embryonal renal tumour, usually in children.
B. Angiomyolipoma is a mesenchymal lesion containing variable fat, vessels and smooth muscle.
C. Clear-cell RCC is a renal parenchymal tumour and does not match the specified urothelial differentiation.
- Urothelial carcinoma can arise in the renal pelvis, ureter or bladder.
- Haematuria alone does not distinguish RCC from urothelial carcinoma.
- A renal-pelvis tumour and a renal cortical mass require different pathological differentials.
Q195. A symptomatic patient has acute hepatitis after travel. Which antibody result supports recent hepatitis A infection?
Appeared in (recall papers): September 2017
A. IgM anti-HAV
B. Antimitochondrial antibody
C. Anti-thyroglobulin antibody
D. Isolated IgG anti-HAV
Answer and explanation
A. IgM anti-HAV
IgM anti-HAV supports recent infection in a clinically compatible acute illness. It should not be used as an indiscriminate screening test because false-positive or prolonged positive results can occur.
B. This is associated with primary biliary cholangitis rather than acute HAV infection.
C. This is a thyroid autoantibody rather than a marker of acute viral hepatitis.
D. IgG generally indicates immunity from past infection or vaccination and does not establish acute infection.
- Travel destination alone does not prove the cause of jaundice.
- HAV usually causes acute infection without a chronic carrier state.
- The serological result must be interpreted in the symptomatic clinical context.
Q196. Why does functional asplenia in sickle cell disease increase the risk of invasive pneumococcal infection?
Appeared in (recall papers): 2021 (session not specified)
A. Reduced splenic clearance of encapsulated bacteria
B. Defective neutrophil oxidative burst as the defining lesion
C. Isolated terminal-complement deficiency as the defining lesion
D. Profound CD4 depletion as the defining lesion
Answer and explanation
A. Reduced splenic clearance of encapsulated bacteria
The spleen contributes to recognition and removal of encapsulated organisms from blood. Loss of this function increases susceptibility to invasive infection.
B. Oxidative-burst failure characterises chronic granulomatous disease rather than the principal asplenic mechanism.
C. Terminal-complement deficiency particularly predisposes to Neisseria and does not define functional asplenia.
D. Severe CD4 depletion causes a different pattern of opportunistic susceptibility and does not define sickle-cell-associated asplenia.
- Streptococcus pneumoniae is encapsulated.
- Vaccination and age-appropriate prophylaxis reduce risk, but fever still warrants prompt assessment.
- Asplenia predisposes to other encapsulated organisms as well as pneumococcus.
Q197. The atypical circulating lymphocytes in acute EBV infectious mononucleosis are predominantly which cells?
Appeared in (recall papers): May 2022; Paper/session not recorded in source
A. Activated CD8 T lymphocytes
B. Mature monocytes
C. Activated CD4 T cells as the predominant population
D. EBV-infected B lymphocytes as the predominant atypical blood-film cells
Answer and explanation
A. Activated CD8 T lymphocytes
The striking atypical lymphocytes are mainly reactive cytotoxic T cells responding to infected cells. They should not automatically be interpreted as a malignant lymphoid population.
B. The name mononucleosis does not mean the characteristic atypical cells are simply mature monocytes.
C. CD4 cells participate in immune responses, but CD8 expansion predominates in the characteristic atypical circulating response.
D. EBV targets B cells, but the conspicuous reactive atypical circulating cells are predominantly activated T cells.
- EBV infects B cells, while many conspicuous circulating reactive cells are T cells.
- Clinical findings and an appropriate antibody pattern are needed to establish acute EBV infection.
- Reactive atypia in an acute infection differs from a proven clonal lymphoma.
Q198. A rapidly enlarging node is effaced by diffuse sheets of large malignant mature B cells. Which diagnosis best fits?
Appeared in (recall papers): January 2019; September 2020; September 2021
A. Follicular lymphoma
B. Diffuse large B-cell lymphoma
C. Classic Hodgkin lymphoma
D. Small lymphocytic lymphoma
Answer and explanation
B. Diffuse large B-cell lymphoma
DLBCL is an aggressive mature B-cell lymphoma with large neoplastic cells in a diffuse growth pattern. Final classification integrates morphology, immunophenotype and relevant molecular findings.
A. Conventional follicular lymphoma has a follicular architecture rather than the specified diffuse large-cell pattern.
C. Classic Hodgkin lymphoma typically has sparse diagnostic tumour cells in a characteristic inflammatory background rather than diffuse sheets of malignant mature B cells.
D. SLL is predominantly a small-cell mature B-cell neoplasm.
- Generalised lymphadenopathy alone cannot distinguish lymphoma subtypes.
- A tissue diagnosis is needed; anaemia morphology does not establish the lymphoma lineage.
- A diffuse large-cell pattern must still be assessed for other defined large B-cell lymphoma entities.
Q199. A woman with a previously confirmed ER-positive breast carcinoma has a lytic femoral lesion. Biopsy matches the breast tumour and is ER- and GATA3-positive. What does the bone lesion represent?
Appeared in (recall papers): January 2017; January 2019
A. Multiple myeloma
B. Primary osteosarcoma
C. Metastatic breast carcinoma
D. Primary chondrosarcoma
Answer and explanation
C. Metastatic breast carcinoma
Matching morphology and a compatible marker profile support spread from the known breast primary. The lytic appearance alone would not have identified the primary site.
A. Myeloma is a plasma-cell disorder, not a lesion matching an epithelial breast primary.
B. Osteosarcoma requires malignant osteoid and does not fit the matching epithelial breast-tumour phenotype.
D. Chondrosarcoma produces malignant cartilage rather than the specified metastatic epithelial cells.
- GATA3 is not entirely breast-specific and must be interpreted as part of a panel and clinical context.
- A suspicious solitary bone lesion in a cancer patient still requires appropriate assessment rather than an automatic metastasis assumption.
- Bone lesions can be metastatic, primary malignant or benign even in someone with a previous cancer.
Q200. A patient has characteristic acute epigastric pain and serum lipase five times the upper limit of normal. Which diagnosis is supported by these two findings?
Appeared in (recall papers): May 2022; May 2023; Paper/session not recorded in source
A. Chronic pancreatic insufficiency alone
B. Isolated Gilbert syndrome
C. Uncomplicated biliary colic alone
D. Acute pancreatitis
Answer and explanation
D. Acute pancreatitis
Typical pain and pancreatic enzymes above three times the upper limit fulfil two standard diagnostic criteria. Characteristic imaging is the third criterion, of which two are generally required.
A. Chronic exocrine insufficiency typically causes maldigestion rather than this acute diagnostic presentation.
B. Gilbert syndrome causes unconjugated hyperbilirubinaemia, not this pancreatic pain-and-enzyme pattern.
C. Biliary colic does not adequately explain this diagnostic combination, although gallstones can cause pancreatitis.
- The enzyme elevation does not identify whether the cause is gallstones, alcohol or another process.
- Enzyme height alone is not a reliable measure of pancreatitis severity.
- A patient meeting two diagnostic criteria does not invariably need immediate CT solely to establish the diagnosis.
Q201. A young adult has fever, pharyngitis, cervical lymphadenopathy and splenomegaly. EBV VCA IgM is positive and EBNA antibody is absent. What is the most likely diagnosis?
Appeared in (recall papers): May 2022; Paper/session not recorded in source
A. Chronic myeloid leukaemia
B. Cirrhotic portal hypertension
C. Hodgkin lymphoma
D. Infectious mononucleosis
Answer and explanation
D. Infectious mononucleosis
The clinical syndrome and antibody pattern support primary EBV infection. A high EBV IgG titre alone would not establish acute infection.
A. This requires a compatible myeloid blood picture and BCR::ABL1 evidence; acute EBV serology supports a different explanation.
B. This can cause splenomegaly but does not explain the acute pharyngitis and EBV antibody pattern.
C. Lymphoma requires tissue assessment and is not established by lymphadenopathy alone.
- VCA IgG can persist for life after infection.
- EBNA antibodies usually appear later, rather than during acute primary infection.
- Acute EBV serology needs clinical interpretation; EBV IgG positivity alone is common in healthy adults.
Q202. A familial thrombophilia is shown to involve factor V resistance to cleavage by activated protein C. Which diagnosis explains this finding?
Appeared in (recall papers): September 2018; January 2019; January 2020; September 2020; January 2021; September 2024; Paper/session not recorded in source
A. Protein C deficiency
B. Antithrombin deficiency
C. Factor V Leiden
D. Antiphospholipid syndrome
Answer and explanation
C. Factor V Leiden
A pathogenic F5 variant makes factor V less susceptible to inactivation by activated protein C. Persistent procoagulant activity increases venous thrombosis risk.
A. This reduces the anticoagulant protein itself rather than making factor V resistant to its action.
B. This impairs inhibition of thrombin and other activated factors, rather than factor V cleavage by activated protein C.
D. APS is an acquired antibody-associated thrombophilia, not an inherited F5 cleavage-site disorder.
- Penetrance is variable; some carriers never develop thrombosis.
- Family history alone does not distinguish the inherited thrombophilias.
- Factor V Leiden increases thrombosis risk; it is not a clotting-factor deficiency causing haemorrhage.
Q203. A thyroid aspirate contains CD20-positive lymphocytes. Which conclusion is justified by this marker alone?
Appeared in (recall papers): January 2025
A. The cells prove papillary thyroid carcinoma
B. The cells identify a medullary carcinoma
C. The cells show B-cell differentiation, but malignancy is not established
D. The cells definitively prove thyroid lymphoma
Answer and explanation
C. The cells show B-cell differentiation, but malignancy is not established
CD20 identifies B-cell differentiation in this setting. Reactive B cells can occur in thyroiditis, so architecture, cytology and clonality must be assessed before diagnosing lymphoma.
A. CD20 is not a diagnostic epithelial marker for papillary carcinoma.
B. Medullary carcinoma shows neuroendocrine differentiation, with calcitonin being an important marker.
D. CD20 positivity alone does not distinguish reactive from neoplastic B cells.
- Hashimoto thyroiditis increases the risk of primary thyroid lymphoma, but most affected patients do not develop lymphoma.
- A rapidly enlarging thyroid mass requires assessment beyond an isolated immunostain.
- CD20 positivity alone must not be used as a substitute for lymphoma diagnosis.
Q204. Which numbered coagulation factor is a cell-surface initiator that complexes with factor VIIa, rather than a circulating hepatic clotting zymogen?
Appeared in (recall papers): January 2017
A. Factor III
B. Factor X
C. Factor II
D. Factor IX
Answer and explanation
A. Factor III
Factor III is tissue factor, a transmembrane protein that initiates coagulation when exposed to blood. Its complex with factor VIIa activates downstream factors, particularly IX and X.
B. Factor X is a vitamin K-dependent circulating protease precursor activated by upstream complexes.
C. Prothrombin is a circulating vitamin K-dependent hepatic precursor of thrombin.
D. Factor IX is a vitamin K-dependent circulating protease precursor, not tissue factor.
- Factors II, VII, IX and X depend on vitamin K for normal functional maturation.
- Factor VIII is a cofactor with predominantly endothelial synthesis and should not be confused with tissue factor.
- Tissue factor exposure links tissue injury to initiation of coagulation.
Q205. A patient with positive coeliac serology undergoes duodenal biopsy while eating gluten. Which pattern supports coeliac disease?
Appeared in (recall papers): May 2023
A. Caseating granulomas containing acid-fast bacilli
B. Broad bands of subepithelial collagen without villous injury
C. Villous atrophy, crypt hyperplasia and increased intraepithelial lymphocytes
D. Transmural inflammation with noncaseating granulomas
Answer and explanation
C. Villous atrophy, crypt hyperplasia and increased intraepithelial lymphocytes
Gluten-related immune injury can produce this characteristic small-bowel mucosal pattern. Histology must be interpreted with serology, gluten exposure and alternative causes of villous injury.
A. This suggests mycobacterial infection rather than coeliac enteropathy.
B. This is not the characteristic coeliac triad.
D. This suggests Crohn disease rather than the typical coeliac mucosal pattern.
- IgA tissue transglutaminase is a commonly used initial serological test; total IgA helps identify IgA deficiency.
- Starting a gluten-free diet before testing can reduce diagnostic sensitivity.
- Granulomas are not a typical defining feature of coeliac disease.
Q206. A raised scar continues growing beyond the boundaries of the original skin wound. What is the most likely diagnosis?
Appeared in (recall papers): April 2025
A. Hypertrophic scar
B. Keloid
C. Atrophic scar
D. Wound dehiscence
Answer and explanation
B. Keloid
A keloid is excessive scar tissue that extends beyond the initial injury. This clinical behaviour distinguishes it from a hypertrophic scar confined to the original wound.
A. This may be thick and raised but stays within the original wound boundaries.
C. An atrophic scar is depressed because of tissue loss rather than a growing elevated scar.
D. Dehiscence is separation of wound edges rather than progressive excessive scar growth.
- Keloids may itch or be painful and may recur after treatment.
- Collagen architecture is abnormal; one exclusive collagen type should not define every keloid.
- A hypertrophic scar may regress, whereas keloids often persist and extend beyond the wound.
Q207. A melanoma on the trunk has a broad radial epidermal component with pagetoid spread of atypical melanocytes. Which subtype best fits this pattern?
Appeared in (recall papers): September 2016
A. Desmoplastic melanoma
B. Nodular melanoma
C. Acral lentiginous melanoma
D. Superficial spreading melanoma
Answer and explanation
D. Superficial spreading melanoma
This subtype commonly shows a lateral or radial growth phase within the epidermis, often with pagetoid atypical melanocytes. Dermal invasion introduces the vertical component relevant to Breslow thickness.
A. This is characterised by invasive spindle cells in a fibrous stroma rather than the typical superficial spreading pattern.
B. This typically has early dominant vertical growth with little or no prolonged radial phase.
C. This is defined by its acral distribution and lentiginous pattern rather than the subtype described here.
- An evolving asymmetric pigmented lesion requires clinical and histological assessment.
- A subtype cannot be diagnosed from a missing photograph or travel history alone.
- Breslow thickness measures invasive melanoma depth rather than its lateral epidermal extent.
Q208. A persistent, well-defined red oral mucosal patch has no other identifiable clinical cause. Which term describes this potentially malignant disorder?
Appeared in (recall papers): September 2018
A. Traumatic ulcer
B. Erythroplakia
C. Pseudomembranous candidiasis
D. Leukoplakia
Answer and explanation
B. Erythroplakia
Erythroplakia describes an otherwise unexplained red oral patch. It warrants biopsy because epithelial dysplasia or carcinoma may already be present; appearance alone does not establish invasion.
A. This involves epithelial loss with an identifiable traumatic context, rather than an unexplained red patch.
C. This typically produces removable whitish plaques and requires evidence of fungal infection.
D. Leukoplakia describes an otherwise unexplained predominantly white patch, rather than a red one.
- Persistent oral red or mixed red-white lesions need careful examination and tissue assessment.
- Keratin production alone does not prove invasive squamous carcinoma.
- Biopsy determines whether dysplasia or invasive malignancy is present in an oral red lesion.
Q209. A patient has fever with rigors, right upper abdominal pain, jaundice and cholestatic liver tests. Imaging shows a dilated common bile duct containing a stone. What is the most likely acute clinical syndrome?
Appeared in (recall papers): September 2021; Paper/session not recorded in source
A. Uncomplicated biliary colic
B. Acute cholangitis
C. Gilbert syndrome
D. Uncomplicated acute cholecystitis
Answer and explanation
B. Acute cholangitis
Infection in an obstructed biliary system explains the systemic inflammation and cholestasis. The duct stone is the underlying obstructing cause rather than the full acute syndrome.
A. This does not explain fever with systemic inflammation and sustained jaundice.
C. Gilbert syndrome causes intermittent unconjugated hyperbilirubinaemia without this inflammatory obstructive picture.
D. Gallbladder inflammation alone does not best explain the infected obstructed common bile duct pattern.
- Charcot triad is fever, right upper abdominal pain and jaundice; it is not present in every case.
- Hypotension or altered mental status suggests severe illness and warrants urgent assessment.
- An obstructing stone and cholangitis may coexist; aetiology and clinical syndrome are different targets.
Q210. A newborn has excessive salivation and choking after feeds. A tube coils in the proximal oesophagus, while abdominal radiography shows gas in the stomach. Which anomaly is most likely?
Appeared in (recall papers): September 2020; September 2021
A. Congenital diaphragmatic hernia
B. Isolated oesophageal atresia without fistula
C. Infantile hypertrophic pyloric stenosis
D. Oesophageal atresia with a distal tracheo-oesophageal fistula
Answer and explanation
D. Oesophageal atresia with a distal tracheo-oesophageal fistula
The coiled tube indicates a blind proximal oesophageal pouch. Gas reaching the stomach supports communication between the distal oesophagus and trachea.
A. This places abdominal viscera in the thorax rather than creating the described blind oesophageal pouch.
B. The blind pouch fits, but a gasless abdomen would be more typical without a distal communication.
C. This causes gastric outlet obstruction, usually after the neonatal period, and does not stop the tube in the proximal oesophagus.
- Polyhydramnios can result from impaired fetal swallowing but is not specific to this anomaly.
- Associated anomalies require assessment, including vertebral, anal, cardiac, renal and limb abnormalities.
- The distal fistula permits air into the stomach despite obstruction of the proximal oesophagus.
Q211. A patient treated for SLE develops osteoporosis and fractures after minimal trauma. Which long-term medication is the most likely contributor?
Appeared in (recall papers): January 2020
A. Systemic glucocorticoid
B. Hydroxychloroquine
C. Azathioprine
D. Methotrexate
Answer and explanation
A. Systemic glucocorticoid
Glucocorticoids impair osteoblast function and bone formation, with additional effects on resorption and bone quality. Long-term exposure increases fragility-fracture risk.
B. This is not the characteristic cause of glucocorticoid-pattern bone loss among the listed drugs.
C. Myelosuppression and infection are important adverse effects; it is not the usual direct cause of this osteoporosis pattern.
D. It has important toxicities and uncommon bone complications, but systemic glucocorticoids are the stronger typical cause in this scenario.
- Vertebral and other fragility fractures may occur during prolonged systemic steroid exposure.
- Fracture risk depends on dose, duration and patient factors, not bone density alone.
- Inflammatory disease, immobility and other patient factors can add to steroid-related skeletal risk.
Q212. Which mechanism contributes directly to aspirin-related gastric mucosal injury?
Appeared in (recall papers): January 2021
A. Inhibition of protective mucosal prostaglandin synthesis
B. Primary stimulation of fibrinolysis
C. Direct inhibition of thrombin
D. Selective factor VIII deficiency
Answer and explanation
A. Inhibition of protective mucosal prostaglandin synthesis
Cyclo-oxygenase inhibition reduces prostaglandin-mediated mucosal protection. Aspirin also impairs platelet function, so mucosal injury and impaired haemostasis can both contribute to bleeding.
B. This is not the principal mechanism of aspirin-related gastric mucosal injury.
C. This describes anticoagulant drugs such as dabigatran rather than aspirin.
D. Aspirin does not characteristically cause an isolated acquired factor VIII deficiency.
- Mucosal prostaglandins support mucus, bicarbonate and mucosal blood flow.
- Aspirin inhibits platelet thromboxane synthesis; platelet count may remain normal.
- An antiplatelet effect does not require thrombocytopenia.
Q213. After gastric bypass, a patient develops sweating, palpitations and confusion two hours after carbohydrate-rich meals. Plasma glucose during an episode is 2.4 mmol/L and symptoms resolve with glucose. Which mechanism is most likely?
Appeared in (recall papers): September 2024; April 2025; Paper/session not recorded in source
A. Exaggerated postprandial insulin secretion
B. Primary glucagon excess
C. Immediate osmotic fluid shifts alone
D. Persistent fasting insulinoma proven by the operation history
Answer and explanation
A. Exaggerated postprandial insulin secretion
Rapid nutrient delivery can produce an exaggerated incretin and insulin response after gastric bypass. Subsequent hypoglycaemia accounts for the delayed autonomic and neuroglycopenic symptoms.
B. Glucagon generally raises blood glucose rather than explaining this insulin-mediated pattern.
C. These contribute to early dumping, usually within the first hour, and do not fully explain the documented delayed hypoglycaemia.
D. The operation history does not prove insulinoma; fasting episodes and a separate biochemical evaluation would be needed.
- Late dumping terminology is often used for meal-related hypoglycaemia one to three hours after surgery-related rapid nutrient delivery.
- Symptoms alone without measured glucose can overlap with other postoperative conditions.
- Fasting or otherwise atypical hypoglycaemia warrants investigation for alternative causes.
Q214. Thirty minutes after a red-cell transfusion starts, a patient develops hypotension, back pain and haemoglobinuria. What is the most likely reaction?
Appeared in (recall papers): Paper/session not recorded in source
A. Delayed haemolytic transfusion reaction
B. Acute haemolytic transfusion reaction
C. Febrile non-haemolytic transfusion reaction
D. Transfusion-related acute lung injury
Answer and explanation
B. Acute haemolytic transfusion reaction
Rapid haemolysis during transfusion can cause back pain, hypotension and haemoglobinuria. ABO incompatibility is an important cause, although the exact incompatibility must be investigated rather than assumed.
A. This usually appears later, often days after transfusion, rather than within thirty minutes.
C. This can cause fever and chills but does not explain intravascular haemolysis; serious alternatives must first be excluded.
D. TRALI causes acute hypoxaemic respiratory failure with pulmonary infiltrates rather than explaining haemoglobinuria.
- Stop a suspected serious transfusion reaction immediately and seek urgent clinical and transfusion-service assistance.
- Assessment includes identity checks, blood grouping, DAT and haemolysis investigations.
- ABO-incompatible transfusion can cause severe intravascular haemolysis, shock and DIC.
Q215. Eight days after transfusion, a previously transfused patient develops jaundice, a falling haemoglobin and a newly detectable red-cell alloantibody. Which mechanism best explains this?
Appeared in (recall papers): Paper/session not recorded in source
A. Isolated circulatory overload
B. Isolated cytokine-mediated febrile non-haemolytic reaction
C. An anamnestic response to a red-cell antigen
D. Immediate ABO-incompatible haemolysis during the infusion
Answer and explanation
C. An anamnestic response to a red-cell antigen
A previously formed alloantibody can fall below detection and rise rapidly after re-exposure. This secondary response can destroy transfused red cells and cause delayed haemolysis.
A. Volume overload causes a cardiopulmonary presentation rather than antibody-associated haemolysis.
B. This does not explain delayed red-cell destruction with a newly detected alloantibody.
D. This is the classic acute presentation rather than the specified delayed secondary antibody response.
- A delayed haemolytic reaction may have a positive DAT, raised LDH and an inadequate haemoglobin increment.
- Record historical clinically significant antibodies even when they later become undetectable.
- Jaundice alone does not establish the timing or mechanism of a transfusion reaction.
Q216. A painless finger lump develops after penetrating trauma. Histology shows a keratin-filled cyst lined by stratified squamous epithelium with a granular layer, without skin appendages. What is the diagnosis?
Appeared in (recall papers): Paper/session not recorded in source
A. True dermoid cyst
B. Digital artery aneurysm
C. Foreign-body granuloma
D. Epidermoid inclusion cyst
Answer and explanation
D. Epidermoid inclusion cyst
Trauma can implant epidermal cells into deeper tissue, where a keratin-filled epithelial cyst forms. Absence of skin appendages helps distinguish an epidermoid cyst from a true dermoid cyst.
A. A dermoid cyst contains skin appendages, such as hair follicles or sebaceous glands, within its wall.
B. This is a vascular dilatation, not a squamous-lined keratin cyst.
C. This is a histiocytic and giant-cell reaction to foreign material rather than the described epithelial-lined keratin cyst.
- Epidermoid cysts may occur in non-hair-bearing skin after traumatic implantation.
- Rupture can release keratin and provoke inflammation.
- A true dermoid cyst has dermal appendages; an epidermoid cyst does not.
Q217. Chalky white deposits surround a necrotic pancreas. Which mechanism produces these deposits?
Appeared in (recall papers): January 2025
A. Amyloid deposition from immunoglobulin light chains
B. Calcium binding to fatty acids released by lipase
C. Keratin accumulation within squamous nests
D. Urate deposition after purine breakdown
Answer and explanation
B. Calcium binding to fatty acids released by lipase
Pancreatic lipase releases fatty acids from damaged adipocytes. These combine with calcium to form insoluble soaps, producing saponification.
A. Amyloid is a fibrillary protein deposit, not a calcium-fatty-acid soap.
C. Keratinisation is an epithelial process, not the mechanism of peripancreatic chalky deposits.
D. Urate deposition forms gouty tophi rather than the typical pancreatic fat-necrosis deposits.
- Fat necrosis may involve peripancreatic and more distant adipose tissue.
- Saponification can contribute to hypocalcaemia during severe pancreatitis.
- Necrotising pancreatitis can involve pancreatic parenchyma, peripancreatic fat, or both.
Q218. A patient with Crohn disease receiving infliximab develops weight loss, fever and haemoptysis. Which infection is particularly important to investigate?
Appeared in (recall papers): January 2025
A. Uncomplicated enterobiasis
B. Localised herpes labialis
C. Tuberculosis
D. Acute hepatitis A
Answer and explanation
C. Tuberculosis
TNF blockade increases the risk of reactivation and new tuberculosis. TNF contributes to host control of mycobacterial infection, including granuloma integrity.
A. Pinworm infection does not explain the pulmonary and constitutional presentation.
B. A local cold sore does not explain the systemic respiratory illness described.
D. This primarily causes an acute hepatic illness rather than explaining this respiratory syndrome.
- Assess for latent tuberculosis before starting a TNF inhibitor.
- Tuberculosis during immunosuppression can be extrapulmonary or disseminated.
- A new pulmonary illness during immunosuppression needs investigation rather than automatic attribution to Crohn disease.
Q219. A sputum sample contains mature squamous cells without reported atypia. What can be concluded from that finding alone?
Appeared in (recall papers): September 2017; September 2018
A. It proves small-cell carcinoma
B. It proves pulmonary tuberculosis
C. It proves invasive lung squamous carcinoma
D. It does not establish lung squamous carcinoma
Answer and explanation
D. It does not establish lung squamous carcinoma
Mature squamous cells can reflect oropharyngeal contamination. Malignancy requires convincing malignant cytology or tissue evidence interpreted with the clinical findings.
A. Small-cell carcinoma has a distinct malignant neuroendocrine morphology, not simply mature squamous cells.
B. Tuberculosis requires appropriate microbiological or pathological evidence, not mature squamous cells alone.
C. The mere presence of squamous cells does not show malignant atypia or invasion.
- Haemoptysis in a smoker still requires appropriate investigation even if this sample is nondiagnostic.
- A specimen finding must be distinguished from a confirmed disease diagnosis.
- Morphologically malignant squamous cells and ordinary mature squamous contamination are different findings.
Q220. A tissue is abnormally small because it never developed its normal complement of cells. Which term describes this?
Appeared in (recall papers): Paper/session not recorded in source
A. Atrophy
B. Hypertrophy
C. Hypoplasia
D. Metaplasia
Answer and explanation
C. Hypoplasia
Hypoplasia is incomplete development of a tissue or organ. It differs from atrophy, which is a reduction in previously developed tissue.
A. Atrophy is acquired shrinkage or loss of previously developed tissue rather than incomplete initial development.
B. Hypertrophy means increased cell size rather than underdevelopment.
D. Metaplasia is replacement of one differentiated cell type by another.
- Aplasia denotes absent or failed development, rather than simply a reduced amount of tissue.
- Congenital disease and later disuse can coexist, so their mechanisms should not be conflated.
- Atrophy may follow disuse, denervation, malnutrition or ischaemia.
Q221. Deficiency of which enzyme causes acute intermittent porphyria?
Appeared in (recall papers): January 2026
A. Ferrochelatase
B. Uroporphyrinogen decarboxylase
C. Glucose-6-phosphate dehydrogenase
D. Hydroxymethylbilane synthase
Answer and explanation
D. Hydroxymethylbilane synthase
Hydroxymethylbilane synthase is also called porphobilinogen deaminase. Reduced activity disrupts haem synthesis and predisposes to acute neurovisceral attacks.
A. Ferrochelatase deficiency is associated with erythropoietic protoporphyria.
B. Deficiency of this enzyme is associated with porphyria cutanea tarda rather than acute intermittent porphyria.
C. This enzyme protects red cells against oxidative injury and is not the haem-synthesis defect in AIP.
- Abdominal pain, autonomic symptoms and neuropathy are important manifestations of an acute attack.
- Urinary porphobilinogen testing during symptoms helps assess suspected acute hepatic porphyria.
- Acute intermittent porphyria usually lacks the photosensitive blistering typical of some other porphyrias.
Q222. A simple fracture is anatomically reduced and compressed with absolute stability. Which healing pattern is expected?
Appeared in (recall papers): April 2025
A. Direct bone healing with little external callus
B. Permanent fibrous union as the normal endpoint
C. Obligatory large fibrocartilaginous callus
D. Endochondral ossification as the only possible mechanism
Answer and explanation
A. Direct bone healing with little external callus
Absolute stability permits direct healing through osteonal remodelling across the fracture. A large external callus is not required for successful union in this setting.
B. Fibrous nonunion is a failure of healing, not the intended result of stable compression.
C. A prominent callus is typical of indirect healing under relative stability rather than an absolute requirement here.
D. Direct healing does not require a large cartilage intermediate.
- Indirect healing remains appropriate when the mechanical environment provides relative stability.
- Interpret callus together with fixation strategy, alignment and symptoms.
- Absence of a large callus is not automatically evidence of failure after compression fixation.
Q223. A biopsy is Congo-red positive, but AL and ATTR amyloidosis remain possible. Which investigation directly identifies the deposited protein?
Appeared in (recall papers): May 2024
A. Using serum calcium alone to label the deposit AL
B. Repeating the Congo-red stain alone
C. Validated tissue amyloid typing by mass spectrometry
D. Using age alone to label the deposit ATTR
Answer and explanation
C. Validated tissue amyloid typing by mass spectrometry
Mass-spectrometry-based tissue typing can identify the amyloid precursor. Congo red establishes amyloid deposition but does not by itself distinguish AL from ATTR.
A. Calcium is not a direct test of amyloid composition.
B. A repeat positive stain does not identify the precursor protein.
D. Age changes probability but cannot definitively type an individual deposit.
- Monoclonal-protein assessment includes serum free light chains and serum and urine immunofixation.
- A monoclonal gammopathy can coexist with ATTR, so interpretation must be clinically integrated.
- Congo red confirms the amyloid pattern; it does not name the precursor protein.
Q224. A renal cortical tumour contains nests of malignant cells with clear cytoplasm and a delicate vascular network. Which diagnosis is most likely?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Wilms tumour
B. Clear-cell renal cell carcinoma
C. Angiomyolipoma
D. Renal-pelvis urothelial carcinoma
Answer and explanation
B. Clear-cell renal cell carcinoma
Clear-cell RCC characteristically has lipid- and glycogen-rich clear cytoplasm and a rich vascular network. It is a renal parenchymal carcinoma rather than a urothelial tumour of the collecting system.
A. Wilms tumour usually occurs in children and classically has blastemal, epithelial and stromal elements.
C. This typically contains fat, abnormal vessels and smooth muscle rather than the malignant epithelial nests described.
D. This arises from urothelium and does not typically have the described clear-cell cortical architecture.
- VHL-pathway alterations are frequent in clear-cell RCC.
- Haematuria in a smoker does not alone distinguish a renal parenchymal from a urothelial primary.
- An imaging finding described only as a kidney mass does not specify its histological subtype.
Q225. A young adult returns from Bangladesh with anorexia, vomiting and jaundice. Which listed infection is the most likely cause?
Appeared in (recall papers): September 2017
A. Ascariasis
B. Hepatitis C
C. Campylobacter enteritis
D. Hepatitis A
Answer and explanation
D. Hepatitis A
This acute hepatic illness after travel is compatible with hepatitis A. Among the listed choices it is the best fit, although laboratory testing is needed to confirm the individual diagnosis.
A. Ascaris can cause biliary disease, but the vignette does not describe a painful obstructive or cholangitic syndrome.
B. Hepatitis C can cause hepatitis, but it is not the strongest listed fit for this acute travel-associated illness without a blood exposure history.
C. This usually causes an intestinal illness and is not the best explanation for the principal acute hepatitis pattern.
- Hepatitis A spreads primarily by the faecal-oral route.
- IgM anti-HAV supports recent infection in an appropriate clinical context.
- Hepatitis A does not cause chronic viral infection.
Q226. After splenectomy for hereditary spherocytosis, haemolysis improves but spherocytes remain on the film. Why?
Appeared in (recall papers): January 2021
A. The inherited red-cell membrane defect persists
B. Splenectomy normally produces factor VIII deficiency
C. Splenectomy replaces the abnormal membrane genes
D. Persistent spherocytes prove autoimmune haemolysis
Answer and explanation
A. The inherited red-cell membrane defect persists
Splenectomy reduces splenic destruction of poorly deformable cells. It does not repair the inherited membrane abnormality, so the abnormal red-cell shape can persist.
B. Factor VIII deficiency is not the mechanism of hereditary spherocytosis.
C. Removing the spleen does not change the erythroid genome.
D. Spherocytes can persist in hereditary disease and are not specific for an autoimmune cause.
- Membrane and cytoskeletal proteins, including spectrin and ankyrin, may be affected.
- New jaundice after splenectomy still needs assessment rather than automatic attribution to Gilbert syndrome.
- Splenectomy reduces haemolysis but creates a separate risk of serious infection.
Q227. An otherwise well patient has a markedly prolonged aPTT, normal PT and no bleeding history. Mixing corrects the aPTT and factor XII activity is very low. What is expected?
Appeared in (recall papers): April 2017; April 2018; January 2021; May 2022
A. No characteristic clinical bleeding tendency from factor XII deficiency
B. Severe spontaneous haemarthroses as the defining feature
C. A diagnostic confirmation of thrombocytopenia
D. An isolated prolonged PT with normal aPTT
Answer and explanation
A. No characteristic clinical bleeding tendency from factor XII deficiency
Factor XII is important for contact activation in the laboratory aPTT assay. Its deficiency can markedly prolong the test without causing the bleeding phenotype of haemophilia.
B. These are more characteristic of severe factor VIII or IX deficiency.
C. Clotting-factor activity and platelet count measure different components of haemostasis.
D. This is the opposite of the specified laboratory pattern.
- A prolonged screening test does not always predict surgical bleeding.
- Use the clinical history and specific factor or inhibitor investigations to interpret an abnormal aPTT.
- Deficiencies of factors VIII and IX can prolong aPTT and cause deep bleeding; factor XII behaves differently.
Q228. A child has delayed postoperative bleeding despite normal platelet count, PT and aPTT. Which listed deficiency should be considered?
Appeared in (recall papers): April 2025
A. Factor VII
B. Factor VIII
C. Factor XIII
D. Factor XII
Answer and explanation
C. Factor XIII
Factor XIII cross-links and stabilises fibrin after the clot has formed. Deficiency may therefore cause delayed bleeding despite normal routine clotting times.
A. Factor VII deficiency usually prolongs PT.
B. A substantial factor VIII deficiency generally prolongs aPTT rather than leaving the screening pattern normal.
D. Factor XII deficiency prolongs aPTT but does not cause a characteristic bleeding disorder.
- Umbilical-stump bleeding is an important presentation of severe congenital factor XIII deficiency.
- Normal screening tests do not exclude every coagulation or platelet disorder.
- A specific factor XIII activity assay is needed when the clinical suspicion remains despite normal screening tests.
Q229. A boy and his sister have excessive bleeding after dental extraction, normal PT and a prolonged aPTT. Factor VIII and IX activities are normal. Which listed deficiency best fits?
Appeared in (recall papers): 2022 or 2023 (session not specified); April 2025
A. Factor VII
B. Factor VIII
C. Factor XII
D. Factor XI
Answer and explanation
D. Factor XI
Factor XI deficiency can cause procedure-related bleeding in either sex and usually follows autosomal inheritance. Bleeding risk varies substantially and is not predicted reliably by the factor level alone.
A. Factor VII deficiency usually prolongs PT, rather than producing this isolated aPTT pattern.
B. The specified normal factor VIII activity argues against haemophilia A.
C. Factor XII deficiency can prolong aPTT but does not explain a characteristic clinical bleeding tendency.
- Oral and other tissues with high fibrinolytic activity may be important sites of bleeding.
- The usual inherited forms of haemophilia A and B are X-linked, unlike most factor XI deficiency.
- Coagulation-factor results and clinical phenotype should be interpreted together.
Q230. Which statement best describes itching in cholestatic liver disease?
Appeared in (recall papers): April 2021
A. It is directly proportional to serum bilirubin in every patient
B. Several pruritogenic pathways contribute; bile acids are implicated
C. ALP crystals deposited in skin are the established cause
D. It proves an IgE-mediated allergy to bile
Answer and explanation
B. Several pruritogenic pathways contribute; bile acids are implicated
Cholestatic itch has a complex mechanism involving retained and circulating pruritogens. It should not be explained solely by bilirubin or a simple amount of bile-salt deposition in skin.
A. Bilirubin concentration does not reliably predict itch severity.
C. ALP is an enzyme marker of cholestasis, not an established crystalline pruritogen.
D. Cholestatic pruritus is not simply an IgE-mediated allergic reaction.
- Pruritus can be severe even without marked visible jaundice.
- Bile-acid sequestrants can improve symptoms, but response does not establish a single universal mechanism.
- Itch intensity is not a simple measure of bilirubin concentration or liver failure severity.
Q231. Which vascular change contributes to endothelial dysfunction in a chronic cigarette smoker?
Appeared in (recall papers): April 2026
A. Reduced oxidative inactivation of nitric oxide
B. Increased nitric-oxide-mediated relaxation
C. Reduced bioavailability of nitric oxide through oxidative stress
D. Reduced endothelial adhesion-molecule expression
Answer and explanation
C. Reduced bioavailability of nitric oxide through oxidative stress
Smoking promotes oxidative stress and reduces effective nitric-oxide signalling. This impairs normal endothelium-dependent vasodilatation and contributes to vascular injury.
A. Oxidative stress increases rather than reduces loss of effective nitric-oxide signalling.
B. This is contrary to the characteristic smoking-associated impairment of endothelial vasodilatation.
D. Smoking promotes inflammatory activation rather than this protective endothelial change.
- Nitric oxide normally helps restrain platelet activation and vascular smooth-muscle contraction.
- Oxidative injury, inflammation and altered thrombosis all contribute to smoking-related vascular disease.
- Reduced nitric-oxide signalling favours vasoconstriction and an adverse vascular environment.
Q232. In obstructive appendicitis, rising luminal pressure initially impairs low-pressure outflow. Which change can progress to ischaemia and gangrene?
Appeared in (recall papers): January 2026
A. Systemic platelet destruction as the initiating event
B. Impaired venous drainage with progressive wall congestion
C. Primary arterial embolism as the usual initiating event
D. Immune-complex vasculitis as the defining lesion
Answer and explanation
B. Impaired venous drainage with progressive wall congestion
Increasing luminal pressure can obstruct venous and lymphatic drainage. Continued congestion and pressure impair perfusion, allowing necrosis and perforation.
A. Platelet destruction does not explain the pressure-driven local outflow impairment.
C. A primary embolus is not the usual initiating mechanism in obstructive appendicitis.
D. Vasculitis is not the defining vascular mechanism of ordinary obstructive appendicitis.
- Luminal obstruction is an important pathway but does not account for every case of appendicitis.
- A gangrenous appendix has tissue necrosis beyond uncomplicated mucosal inflammation.
- Neutrophils in muscularis propria support acute appendicitis histologically.
Q233. An older adult has unexplained axillary and inguinal lymphadenopathy with anaemia. Which listed diagnosis is the strongest initial suspicion?
Appeared in (recall papers): January 2019; September 2020; September 2021
A. Gastric carcinoma
B. Non-Hodgkin lymphoma
C. Bronchial carcinoma
D. Hodgkin lymphoma
Answer and explanation
B. Non-Hodgkin lymphoma
NHL is a strong diagnostic consideration in an older adult with widespread noncontiguous lymphadenopathy. Anaemia is nonspecific, and the lymphoma diagnosis and subtype still require appropriate tissue assessment.
A. Iron deficiency may require gastrointestinal assessment, but it does not establish gastric cancer and the nodal distribution particularly raises lymphoma.
C. A lung primary can metastasise to nodes, but no primary lung features are supplied and the widespread superficial distribution favours lymphoma.
D. Hodgkin lymphoma can involve several nodal regions, but NHL is a stronger initial consideration with this age and widespread pattern; tissue is needed to distinguish them.
- Age and nodal distribution guide probability but do not replace histological diagnosis.
- Consider infection and other systemic causes while arranging appropriate tissue assessment.
- Do not attribute every abnormal blood result to lymphoma without investigating other causes.
Q234. A patient with biopsy-proven Hodgkin lymphoma has lost 12% of body weight unintentionally over six months. Which symptom category applies?
Appeared in (recall papers): September 2024; January 2025; April 2026
A. A symptoms because fever is absent
B. Stage IV solely because weight was lost
C. An E designation solely because weight was lost
D. B symptoms
Answer and explanation
D. B symptoms
Unexplained loss of more than 10% of body weight in six months is a B symptom. Unexplained fever and drenching night sweats are the other classic defining symptoms.
A. Any qualifying B symptom is sufficient; all three are not required.
B. Weight loss does not itself establish disseminated extranodal disease.
C. E describes qualifying extranodal extension, not constitutional symptoms.
- Pruritus alone does not qualify as a B symptom.
- Anatomical stage and constitutional symptom designation are separate assessments.
- Constitutional symptoms can affect prognostic assessment without changing the anatomical compartment of nodal disease.
Q235. A patient with confirmed renal cell carcinoma develops a skeletal metastasis. Which pattern is most characteristic?
Appeared in (recall papers): January 2017; January 2019
A. A purely inflammatory joint effusion without bone involvement
B. Destructive osteolytic disease, often hypervascular
C. A benign cartilage cap on every lesion
D. Uniform osteoblastic sclerosis as the usual pattern
Answer and explanation
B. Destructive osteolytic disease, often hypervascular
RCC bone metastases are typically osteolytic and can be highly vascular. They may cause pain, structural failure and pathological fracture.
A. That does not describe a skeletal metastasis.
C. This describes an osteochondroma pattern, not metastatic carcinoma.
D. A predominantly sclerotic pattern is more classically associated with prostate carcinoma, although exceptions occur.
- Breast, thyroid, lung and renal primaries can all produce lytic skeletal lesions.
- Imaging alone cannot reliably assign the primary in an otherwise unexplained lytic lesion.
- Hypervascular skeletal lesions require careful planning of any diagnostic or operative procedure.
Q236. Which cellular activity predominates in the initial osteolytic phase of Paget disease of bone?
Appeared in (recall papers): January 2025
A. Excessive osteoclastic bone resorption
B. Selective complete absence of osteoclasts
C. Deposition of urate crystals in every bone
D. Neoplastic cartilage production as the defining process
Answer and explanation
A. Excessive osteoclastic bone resorption
Overactive osteoclasts produce the initial lytic change. Coupled but disorganised bone formation follows, producing mixed and later sclerotic patterns.
B. This would not explain accelerated osteolysis.
C. Urate deposition is not the mechanism of Paget disease.
D. That suggests a cartilage-producing tumour rather than the defining Paget process.
- Later mixed disease includes increased resorption and bone formation.
- The resulting bone can be enlarged yet mechanically disorganised.
- Pagetic bone may predispose to deformity, arthritis and pathological fracture.
Q237. Which listed gene is particularly associated with hereditary breast and ovarian cancer predisposition?
Appeared in (recall papers): January 2016
A. RET
B. APC
C. BRCA1
D. VHL
Answer and explanation
C. BRCA1
Pathogenic BRCA1 variants increase susceptibility to breast and ovarian cancer. A family history raises suspicion but does not prove that a particular person carries a pathogenic variant.
A. RET is associated with MEN2 and hereditary medullary thyroid carcinoma.
B. APC is classically associated with familial adenomatous polyposis.
D. VHL predisposes to a different tumour spectrum, including clear-cell renal carcinoma and haemangioblastomas.
- BRCA2 is another major hereditary breast and ovarian cancer susceptibility gene.
- Genetic assessment uses the wider personal and family history, not one relative alone.
- Pathogenic BRCA variants affect DNA-repair pathways, but a single affected relative does not establish genotype.
Q238. Why can thyroglobulin fail as a reliable tumour marker in anaplastic thyroid carcinoma?
Appeared in (recall papers): 2022 or 2023 (session not specified)
A. Thyroglobulin is produced only by pituitary cells
B. All anaplastic tumours originate from parafollicular C cells
C. TSH completely excludes tumour recurrence
D. Loss of follicular differentiation can eliminate thyroglobulin expression
Answer and explanation
D. Loss of follicular differentiation can eliminate thyroglobulin expression
Anaplastic transformation is associated with loss of differentiated thyroid features. Tumour tissue may therefore express little or no thyroglobulin despite substantial disease.
A. Thyroglobulin is a thyroid follicular product rather than a pituitary hormone.
B. That lineage is associated with medullary carcinoma, not the defining origin of all anaplastic tumours.
C. A TSH result cannot by itself exclude recurrence.
- Thyroglobulin is principally useful in the appropriate follow-up of differentiated thyroid carcinoma.
- A negative differentiation marker does not exclude an anaplastic thyroid primary.
- Marker expression can be lost as a tumour becomes less differentiated.
Q239. Invasive melanoma cells reach the inked peripheral edge of an excision specimen. What does this indicate?
Appeared in (recall papers): January 2026
A. A clear margin regardless of the ink
B. Proven distant metastatic disease
C. A Breslow thickness of zero
D. An involved peripheral histological margin
Answer and explanation
D. An involved peripheral histological margin
Tumour at the inked cut surface indicates an involved margin in that plane. It does not, by itself, determine nodal status or the whole tumour stage.
A. Tumour at the cut surface is not a clear histological margin.
B. A local excision margin does not establish distant metastasis.
C. Breslow thickness measures invasive depth, not whether the lateral margin is involved.
- Peripheral and deep margins should be assessed separately.
- Definitive surgical planning also depends on staging and the overall clinical context.
- A positive margin identifies local cut-surface involvement; it is not synonymous with metastatic disease.
Q240. A patient with rheumatoid arthritis has nocturnal tingling in the thumb, index and middle fingers with thenar weakness. Which lesion best explains this pattern?
Appeared in (recall papers): September 2019
A. Median nerve compression in the carpal tunnel
B. Ulnar nerve compression at the elbow
C. Isolated suprascapular neuropathy
D. Radial nerve injury in the spiral groove
Answer and explanation
A. Median nerve compression in the carpal tunnel
Swollen flexor tenosynovium can increase pressure within the carpal tunnel. Compression of the median nerve produces the characteristic sensory distribution and can weaken thenar function.
B. This more typically affects the little finger, ulnar half of the ring finger and ulnar-innervated intrinsic muscles.
C. This affects shoulder function rather than the median-nerve territory of the hand.
D. This chiefly produces wrist and finger extension weakness rather than this sensory pattern.
- Rheumatoid arthritis is an associated risk factor for carpal tunnel syndrome.
- A histological rheumatoid nodule and a compressive neuropathy are different pathological targets.
- Persistent sensory loss or thenar weakness warrants assessment for significant nerve compression.
Q241. Which triglyceride result most strongly supports hypertriglyceridaemia as a possible cause of acute pancreatitis?
Appeared in (recall papers): May 2023; Paper/session not recorded in source
A. 1600 mg/dL, approximately 18.1 mmol/L
B. 260 mg/dL, approximately 2.9 mmol/L
C. 150 mg/dL, approximately 1.7 mmol/L
D. 90 mg/dL, approximately 1.0 mmol/L
Answer and explanation
A. 1600 mg/dL, approximately 18.1 mmol/L
A very high triglyceride concentration is a recognised cause of pancreatitis. Levels above approximately 1000 mg/dL support this possibility far more strongly than a mild or moderate elevation, while other causes still need assessment.
B. This is elevated but is much weaker evidence for a primary triglyceride aetiology than the severe level listed.
C. This does not represent the marked elevation typical of triglyceride-mediated pancreatitis.
D. This is not a hypertriglyceridaemic result.
- Risk is continuous and increases before 1000 mg/dL; this is not an absolute biological cutoff.
- Triglyceride concentration can fall after fasting and treatment, so sampling timing matters.
- A mildly raised triglyceride level should not end the search for other causes of pancreatitis.
Q242. During transfusion, a patient develops isolated fever and chills. Assessment excludes haemolysis, bacterial contamination and other serious reactions. What is the most likely diagnosis?
Appeared in (recall papers): January 2025
A. Acute haemolytic transfusion reaction
B. Febrile non-haemolytic transfusion reaction
C. Delayed haemolytic transfusion reaction
D. Transfusion-transmitted bacterial sepsis
Answer and explanation
B. Febrile non-haemolytic transfusion reaction
FNHTR can produce fever and chills during or soon after transfusion. It is a diagnosis of exclusion, so serious causes of a transfusion-associated fever must first be assessed.
A. This has been excluded by the specified assessment rather than by a normal blood pressure alone.
C. This usually presents later with evidence of red-cell destruction rather than the isolated immediate episode described.
D. This must be considered urgently but is excluded in the reconstructed scenario.
- A normal blood pressure does not by itself exclude a serious transfusion reaction.
- Stop the transfusion and assess according to the suspected reaction and local protocol.
- Fever during transfusion must not be labelled benign on the basis of normal blood pressure alone.
Q243. During rapid massive transfusion, ionised calcium falls. Which transfused component additive chiefly explains this?
Appeared in (recall papers): January 2025
A. Sodium chloride as a calcium-binding anticoagulant
B. Citrate
C. Adenine as a direct calcium chelator
D. Dextrose as the principal calcium chelator
Answer and explanation
B. Citrate
Citrate binds ionised calcium and is normally metabolised after transfusion. Rapid administration or impaired metabolism can cause clinically important hypocalcaemia.
A. Saline does not account for this specific additive effect.
C. Adenine supports red-cell metabolism and is not the principal calcium-binding anticoagulant.
D. Dextrose is not the main additive responsible for citrate-related hypocalcaemia.
- Monitor ionised rather than total calcium when assessing acute citrate-related changes.
- Hypothermia and haemostatic abnormalities can also complicate massive transfusion.
- Impaired citrate clearance can increase susceptibility to ionised hypocalcaemia.
Q244. A patient has vitamin D deficiency with bone pain and Looser zones. Which laboratory pattern most supports osteomalacia?
Appeared in (recall papers): May 2022
A. Normal calcium, phosphate and ALP as a defining requirement
B. High calcium with suppressed PTH and normal ALP
C. Persistently very low ALP as the typical response
D. Raised ALP with low or low-normal calcium and reduced phosphate
Answer and explanation
D. Raised ALP with low or low-normal calcium and reduced phosphate
Vitamin D deficiency impairs mineralisation and can provoke secondary hyperparathyroidism. Increased bone turnover raises ALP, while reduced calcium absorption and renal phosphate loss contribute to the biochemical pattern.
A. That profile is more typical of uncomplicated primary osteoporosis; osteomalacia values vary with stage.
B. This does not describe the usual vitamin D-deficiency osteomalacia pattern.
C. A low ALP should prompt other possibilities, including hypophosphatasia, rather than being called typical vitamin D-deficiency osteomalacia.
- Looser zones are pseudofractures associated with defective mineralisation.
- Osteoporosis reduces bone quantity; osteomalacia impairs mineralisation of osteoid.
- Vitamin D-deficiency osteomalacia may cause secondary hyperparathyroidism and renal phosphate loss.
Q245. A well-circumscribed nerve-sheath tumour has Antoni A and B areas with Verocay bodies. Which diagnosis is most likely?
Appeared in (recall papers): January 2025
A. Schwannoma
B. Meningioma
C. Neurofibroma
D. Malignant peripheral nerve-sheath tumour
Answer and explanation
A. Schwannoma
Schwannomas are composed of neoplastic Schwann cells and often show alternating cellular and loose areas. Nuclear palisading around acellular zones forms Verocay bodies.
B. Meningiomas characteristically form meningothelial whorls and may contain psammoma bodies.
C. Neurofibromas have a mixed cellular composition and do not typically show this organised Antoni A/B architecture.
D. This typically has malignant cytological and growth features rather than the classic benign architecture specified.
- Strong S100 and SOX10 expression often supports Schwann-cell differentiation.
- Interpret morphology and immunostains together rather than naming every S100-positive lesion schwannoma.
- A benign peripheral nerve-sheath tumour is different from a malignant spindle-cell sarcoma.
Q246. Complete common bile duct obstruction reduces which pigment responsible for the normal brown colour of stool?
Appeared in (recall papers): January 2018
A. Stercobilin
B. Melanin
C. Haemoglobin
D. Urinary conjugated bilirubin
Answer and explanation
A. Stercobilin
Biliary bilirubin normally undergoes intestinal bacterial metabolism and conversion into faecal pigments including stercobilin. Complete obstruction reduces pigment delivery and can produce pale stools.
B. Melanin pigments skin and related tissues, not normal stool.
C. Intact haemoglobin is not the normal pigment pathway responsible for brown stool.
D. This accounts for dark urine in conjugated hyperbilirubinaemia, not the normal faecal pigment.
- Dark urine and pale stools arise through different consequences of conjugated hyperbilirubinaemia and reduced intestinal bile delivery.
- Steatorrhoea also reflects inadequate bile-acid delivery for fat absorption.
- Conjugated bilirubin can enter urine because it is water soluble.
Q247. Years after total gastrectomy, a patient develops macrocytic anaemia and distal paraesthesiae. Which deficiency best explains both findings?
Appeared in (recall papers): September 2017; January 2020; January 2021; September 2021
A. Vitamin B12
B. Vitamin K
C. Isolated iron deficiency
D. Vitamin C
Answer and explanation
A. Vitamin B12
Loss of gastric parietal cells removes intrinsic-factor production, impairing normal ileal cobalamin absorption. Deficiency can cause megaloblastic anaemia and neurological dysfunction.
B. Vitamin K deficiency affects haemostasis rather than producing the characteristic macrocytic neuropathic syndrome.
C. Iron deficiency can follow gastric surgery but usually causes microcytosis and does not best explain this neurological-megaloblastic combination.
D. Scurvy causes connective-tissue and bleeding manifestations rather than this characteristic post-gastrectomy combination.
- Body stores can delay the onset of cobalamin deficiency for years.
- Folate can improve anaemia without correcting B12-related neurological injury, so assess the underlying deficiency.
- Cobalamin is absorbed in the terminal ileum after binding intrinsic factor.
Q248. A patient with emphysema has expiratory flow limitation and hyperinflation. Which lung-volume change is expected?
Appeared in (recall papers): April 2021
A. Normal residual volume in every patient
B. Reduced residual volume as the defining change
C. Increased residual volume
D. A mandatory reduction in total lung capacity
Answer and explanation
C. Increased residual volume
Air trapping prevents complete expiration and increases the volume remaining after maximal expiration. Total lung capacity may also rise because of hyperinflation.
A. Air trapping commonly raises RV; a normal result is not a universal requirement.
B. This is contrary to the expected effect of air trapping.
D. A low TLC characterises restrictive disease rather than the usual emphysematous hyperinflation pattern.
- Routine spirometry does not directly measure residual volume.
- Body plethysmography or appropriate gas-dilution methods are used to assess static lung volumes.
- Loss of elastic recoil contributes to expiratory air trapping in emphysema.
Q249. A patient with pre-existing interstitial lung disease needs treatment for a lower UTI. Which listed antibiotic particularly warrants caution because of recognised pulmonary toxicity?
Appeared in (recall papers): January 2024
A. Trimethoprim
B. Amoxicillin
C. Nitrofurantoin
D. Cefuroxime
Answer and explanation
C. Nitrofurantoin
Nitrofurantoin can cause acute and chronic pulmonary reactions. Existing lung disease warrants caution and can obscure recognition of a new adverse reaction; it is not a universal absolute contraindication based on lung disease alone.
A. This has other important adverse effects but is not the specific agent described by this warning.
B. This is not the drug with the characteristic nitrofurantoin pulmonary-toxicity warning, although antibiotics can have other adverse reactions.
D. This does not carry the same characteristic chronic nitrofurantoin lung-injury warning.
- New cough or breathlessness during nitrofurantoin treatment requires prompt assessment for pulmonary toxicity.
- Long-term recipients require attention to pulmonary and hepatic adverse effects.
- Existing lung disease is a caution for nitrofurantoin, not a universal absolute contraindication.
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