🦷 Parotid Gland – Clinical Overview

Benign Neoplasms

80% of all salivary gland tumours arise in the parotid gland.

Of these, ~80% are benign.

Growth rate ≠ malignancy: rapid growth doesn't always imply malignancy.

Facial nerve involvement = red flag for malignancy.

Benign tumors are more common in women (except Warthin's).

Median age: 5th decade.

Benign Tumour Types

Tumour	Features
Pleomorphic adenoma (benign mixed tumour)	Most common (~80%). Involves epithelial + myoepithelial cells. Lobulated, slow-growing, not well-encapsulated. Risk of malignant transformation (2–10%) and recurrence if capsule is violated.
Warthin tumour	2nd most common benign tumour (5%). Occurs in older males, often bilateral or multicentric. Cystic with lymphoid tissue. Rare malignant change.
Monomorphic adenoma	<5% of tumours. Single cell type. Includes oncocytoma, basal cell adenoma, canalicular adenoma, myoepithelioma. Slow-growing.
Haemangioma	Commonest parotid tumour in infants (<1 year). Highly vascular. May regress spontaneously. Rarely becomes malignant.

Malignant Tumours of the Parotid

Type	Features
Mucoepidermoid carcinoma	Most common parotid malignancy (30%). Low-grade types less aggressive.
Adenoid cystic carcinoma	Perineural invasion with skip lesions. High risk of visceral metastasis. 5-year survival: ~35%.
Carcinoma ex-pleomorphic adenoma	Arises from long-standing pleomorphic adenoma.
Acinic cell carcinoma	Intermediate malignancy. Possible perineural spread. 5-year survival: ~80%.
Adenocarcinoma	Arises from secretory units. Risk of nodal + distant spread. Prognosis depends on stage.
Lymphoma	May occur with Warthin’s tumours. Large, rubbery mass. Diagnosis via nodal biopsy. Treated medically (chemo ± radiotherapy).

Diagnostic Workup

• Plain X-ray: rule out stones
• Sialography: ductal anatomy
• FNAC: essential for diagnosis
• CT/MRI: for malignancy assessment
• Superficial parotidectomy: diagnostic + therapeutic for most benign lesions
• Malignancy → formal resection (avoid excisional biopsy)

Treatment

• Benign tumors → Superficial parotidectomy
• Malignant tumors → Radical/extended radical parotidectomy
• Facial nerve resection if involved
• Neck dissection if nodal spread suspected

Other Parotid Conditions

Condition	Features
HIV-associated lymphoepithelial cysts	Bilateral, multicystic swelling. Low malignancy risk. Managed conservatively.
Sjogren syndrome	Autoimmune. Bilateral painless enlargement, dry eyes/mouth. Lymphocytic infiltrates. ↑ Lymphoma risk.
Sarcoidosis	Parotid involved in ~6%. Usually bilateral, painless, with possible xerostomia. Conservative management if isolated.