Details
24 year-old woman with mobile left parotid mass.
Basal cell adenoma is a benign epithelial salivary gland neoplasm that represents 2-3% of all salivary gland tumours. They occur more often in females, with peak incidence in the 6th-7th decade. The most common site is the parotid gland (75%); other sites include the submandibular glands, lips, palate, and buccal mucosa.
Clinically it presents as an asymptomatic, unilateral, solitary and mobile swelling of the affected gland. Histologically it presents as a well-circumscribed, encapsulated lesion with solid, trabecular, tubular, or membranous morphological growth patterns. Two basaloid cell subtypes are present: smaller hyperchromatic basaloid cells surrounding larger, paler basaloid cells in the interior of the tumour nests. Occasional acinar cells and squamous eddies are seen.
Ancillary testing includes keratin, which stains strongest in the inner, larger basaloid cells. S-100, actin-sm, p63, and calponin stains strongest in peripheral basaloid cells.