Cytologic diagnosis of acinic-cell carcinoma of salivary glands.

The cytologic findings in fine-needle aspiration (FNA) biopsies obtained from 40 primary and 18 recurrent acinic-cell carcinomas (ACC) were retrospectively analyzed. Cytomorphologically, ACC is characterized by acinar differentiated tumor cells. In addition to these diagnostic clue cells, other types of neoplastic cells including vacuolated cells, cells resembling oncocytes, and nonspecific glandular cells are encountered. A pronounced lymphocytic reaction is a hallmark in 10% of ACC aspirates. Both the variety of tumor cell differentiation and the pronounced lymphocytic reaction observed in ACC aspirates may result in confusion with other salivary gland lesions. The differential diagnosis of ACC encompasses adenocarcinoma, mucoepidermoid carcinoma, pleomorphic adenoma, Warthin tumor, sebaceous lymphadenoma, benign lymphoepithelial lesion, sialoadenosis, sialadenitis caused by radiotherapy, and lymphadenitis. Primary ACCs were correctly diagnosed in 68%; additionally, ACC was suspected or included in the differential diagnosis in 15%. Increased familiarity with the spectrum of cytomorphologic findings and the potential diagnostic pitfalls in ACC will improve the cytodiagnosis of this neoplasm.