Cytologic diagnosis of adenoid cystic carcinoma of salivary glands

The cytomorphologic features in fine-needle aspiration (FNA) biopsies from 31 primary and 33 recurrent adenoid cystic carcinomas (ACC) were investigat ed The correct FNA diagnosis was established in 24 of 31 primary ACC (77%). The diagnostic clue in aspirates from ACC are large globules of extracellu lar matrix, partially surrounded by basaloid tumor cells. in FNAs with pred ominance of basaloid tumor cells, but lacking characteristic globules, all other benign and malignant salivary gland tumors of epithelial-myoepithelia l differentiation should be considered in the cytologic diagnosis. Pleomorp hic adenoma is most frequently confused with ACC, and therefore, the cytolo gic findings in FNAs from 50 pleomorphic adenomas were compared with those diagnosed as ACC. Furthermore, rare neoplasms of salivary glands with epith elial-myoepithelial cell differentiation, including basal-cell adenoma and carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade a denocarcinoma, as well as some nonsalivary gland neoplasms presenting: an a denoid cystic pattern, must be considered. The cytologic features of these entities are discussed in detail with respect to the cytologic diagnostic c riteria of ACC. (C) 1999 Wiley-Liss, Inc.