Cytomorphological features of Mammary Analog secretory carcinoma of parotid gland: Report of 3 cases and review of literature.

Mammary analog secretory carcinoma (MASC) of salivary gland is a recently described entity. Due to its rarity and cytomorphological overlap with other salivary gland tumors, it is often difficult to recognize on cytology. Here we describe three such cases with their histopathological correlation. All the three tumors arose in the parotid gland. They were misdiagnosed as mucoepidermoid carcinoma, acinic cell carcinoma and salivary duct adenocarcinoma, respectively. Final diagnosis of MASC was established on their follow-up histopathology and immunochemistry evaluation. Cytosmears of these tumors showed high cellularity with papillary architecture lying within fluid background rich in foamy macrophages. Nuclear atypia varied from minimal to marked with frequent mitosis and presence of necrosis. Cytoplasmic vacuolation was a consistent finding. Although the cytomorphological features of MASC are not specific, a diagnosis of MASC should be strongly considered in the presence of papillary architecture, prominent cytoplasmic vacuolations of the tumor cells and a background of cyst fluid. Immunohistochemistry on cell block may be done to confirm the diagnosis.