Abstract
Background: Basal cell adenocarcinoma (BCAC) of the salivary glands is a rare tumor and a recently described entity. A case of BCAC of the parotid gland is reported with the cytological, immunohistochemical, and ultrastructural findings.
Case: A 68-year-old woman presented with a right parotid gland tumor. Computer tomography revealed a tumor measuring 24 mm in diameter, parts of whose boundary were ill-defined. Fine-needle aspiration cytology showed basaloid-cell clumps accompanied by characteristic peripheral features, including palisading, poor cohesiveness, and/or intermingling with fat cells. The basaloid cells had hyperchromatic nuclei and scant cytoplasm. Histologically, the basaloid cells had invaded in a trabecular and/or solid-nest pattern. Immunohistochemistry disclosed dual epithelial and myoepithelial differentiation of the tumor cells. Ki-67 was frequently positive, together with p 53 and EGFR.
Conclusion: Although cytological differential diagnosis between benign and malignant basaloid cell tumors might be very difficult, the poor cell cohesiveness and intermingling with fat cells at the periphery of tumor cell clumps seemed to be characteristic of BCAC.
