Abstract

The myoepithelioma is a rare salivary gland tumor composed nearly exclusively of myoepithelial cells. A case occuring on the parotid gland of a 51 year-old female is reported. Light microscopy finding revealed plasmacytoid cells. Ultrastructurally, the most of the neoplastic cells had polygonal outlines and showed eccentric, round to ovoid nuclei with even contours, peripherally distributed heterochromatin and to three small nuceoli. Their cytoplasms were almost completly filled with thin filaments, arranged in parallel strains and exhibiting "dense bodies". The neoplastic cells showed positive immunostaining for S-100 protein and cytokeratin.

• Keywords: Myoepithelioma;Plasmacytoid cells