Fine Needle Aspiration Cytology of Metastatic Epithelial-Myoepithelial Carcinoma of the Scalp: A Case Report

Kwon, Mi Seon; Lee, Seung Sook; Koh, Jae Soo; Chung, Jin Haeng

Abstract

Epithelial-myoepithelial carcinoma is an uncommon, low grade malignant epithelial neoplasm and metastasis is exceedingly rare. This article highlights the fine needle aspiration cytology(FNAC) of a case of metastatic epithelial-myoepithelial carcinoma of the scalp. A 51-year-old female presented with the left parietotemporal scalp mass two months after the left parotidectomy for epithelial-myoepithelial carcinoma. FNAC from the scalp mass showed a biphasic population of ductal epithelial and myoepithelial origin. These epithelial aggregates were numerous and formed a distinct three dimensional architecture in the background of numerous naked nuclei. The three dimensional architectures were predominantly composed of tightly cohesive eosinophilic ductular epithelial cells which tended to aggregate, overlap, and form tubules. Clear myoepithelial cells in three dimensional tissue fragment were inapparent and a few were attached to the periphery of the fragments. A few myoepithelial cells with clear abundant vaculoated cytoplasm were found in the foamy background. The cytological diagnosis was metastatic epithelial-myoepithelial carcinoma. The histologic findings of the scalp mass were those of typical epithelial-myoepithelial carcinoma. Cytologic distinction of epithelial-myoepithleial carcinoma, pleomorphic adenoma, and adenoid cystic carcinoma may be very difficult but careful attention to clinical features and cellualr details can classify these neoplasms correctly.