Basal Cell Adenoma of Parotid Gland: A Rare Case Report and Review of Literature

Basal cell adenoma of salivary gland is an uncommon type of monomorphic adenoma. Approximately 70 % of basal cell adenomas occur in the parotid gland, the rest involve the minor salivary glands, especially those in the upper lip. It accounts for approximately 1-3 % of all salivary gland tumors. It usually occurs in adult with slight predilection for females. We report a case of 35 year old female who presented with 3x2 cm painless firm fixed swelling in her right parotid region since 6 months. On Fine needle aspiration cytology (FNAC), a diagnosis of basaloid neoplasm was given. Histopathologically, the tumor was characterized by tubular and trabecular areas composed of small isomorphic cells with hyperchromatic, round nuclei and an eosinophilic cytoplasm. The tumour cells were clearly separated by a well-defined basement membrane, and the diagnosis was made as tubular-trabecular type of basal cell adenoma of parotid. On immunohistochemistry, the inner cells of tubular nests were positive for cytokeratin (CK) 7 and that of outer basaloid cells were positive for smooth muscle actin (SMA) and the stromal cells were positive for S100.