Mammary Analogue secretory Carcinoma
of the salivary gland (MAsC).

FNAC: Smear shows low to moderate cellularity featuring a dense eosinophilic, proteinaceous background with bubbly secretions in which there are loosely cohesive small sheets and clusters as well as dispersed, dissociated isomorphic cells with bland nuclear features . On higher power, the nuclei are eccentric, have smooth contours and finely dispersed chromatin with occasional central nucleoli. The cytoplasm is abundant, often elongated (‘hobnail’ shaped) with well defined cell borders .Some cells contain eosinophilic granules and round secretory (‘colloidlike’) material with variable staining intensity on the MGG‐stained smear. Extracellular secretory material stains positive for periodic acid-Schiff (PAS) with and without diastase, mucicarmin and Alcian blue. Intracellular mucin positivity has been described.
Differential diagnosis includes acinic cell carcinoma, low grade cribriform carcinoma, papillary cystadenocarcinoma and low grade mucoepidermid carcinoma. FISH showing ETV6 translocarion is diagnostic.