Fine-needle aspiration biopsy findings in sclerosing polycystic adenosis of the parotid gland.

Sclerosing polycystic adenosis (SPA) is a recently described, rare lesion of the salivary gland analogous to fibrocystic disease of the breast. Recognition of this benign entity is important since the differential diagnosis includes other more common benign and malignant salivary gland neoplasms, particularly mucoepidermoid carcinoma and tumors with cystic and oncocytic features. While the histomorphology of SPA is well documented, there is only one other cytologic description of SPA in the English-language literature. Here we describe the fine-needle aspiration biopsy findings in a case of SPA of the parotid gland in an 84-year-old woman. The aspirate was characterized by flat cohesive sheets of epithelial cells with moderate amounts of finely granular oncocytic cytoplasm and enlarged round nuclei with indistinct nucleoli. Some epithelial groups formed glandular structures with lumens, and the background contained small amounts of delicate mucoproteinaceous material. Occasional markedly vacuolated cells were present as well as many cells with apocrine change manifested by well-defined apical snouting. Familiarity with the cytomorphologic features of SPA, including its characteristic apocrine changes, is important for distinguishing it from other more clinically significant salivary gland lesions.