Cytomorphologic patterns in papillary cystic variant of acinic cell carcinoma of the salivary gland

OBJECTIVE: To study the cytomorphologic profile of the papillary and cystic variant of acinic cell carcinoma (ACC-PCV) of the salivary glands. STUDY DESIGN: We studied 6 aspirates from 5 cases of ACC-PCV. RESULTS: All the cases had varied cytomorphologic features depending upon the degree of vacuolation of cells. However, common to all was a papillary pattern and a cystic fluid background with or without mucin blobs; that led to misdiagnosing the tumor as mucoepidermoid carcinoma on 2 occasions. The smears showed papillary fragments, sheets or clusters of vacuolated/histiocyte like cells and granular cells. The histiocytelike cells resembled macrophages, with finely vacuolated cytoplasm and an eccentrically placed nucleus with frequent binucleation. Vascular cores were seen in a few aspirates. The granular cells were similar to those seen in the usual acinic cell carcinoma but were smaller. The tumor did not show any acinar pattern and lacked naked nuclei in the background. In 4 aspirates finely distributed, brown hemosiderin pigment was detected in the vacuolated cells. CONCLUSION: ACC-PCV is papillary and cystic and hence is often not recognized as acinic cell carcinoma. However, papillary fragments of vacuolated cells or histiocytelike cells and granular cells are clues to the diagnosis.