Cytology of myoepithelial carcinoma of the salivary gland

Abstract

BACKGROUND: Myoepithelial carcinoma, also know as malignant myoepithelioma, is rare in the salivary gland, and its cytologic features have rarely been reported. DESIGN: Four cases of myoepithelial carcinoma with cytology were retrieved from the archives of the Pathology Departments of two academic institutes. In three cases, the specimens were obtained by fine needle aspiration biopsy (FNA); the remaining case was a bench aspiration performed on the surgically resected specimen at the time of intra-operative consultation. The cytologic features were reviewed and correlated with the histology. RESULTS: The four patients with myoepithelial carcinoma (two men and two women) ranged in age from 48 to 64 years. Three cases arose from the parotid gland, and the remaining case was a recurrent tumor in the minor salivary glands of the hard palate. The aspirates of two cases consisted of predominantly spindle cells, one predominantly epithelioid/plasmacytoid cells, and one with a mixture of both spindle and epithelioid/plasmacytoid cells. Cellular pleomorphism was noted in two cases and mitotic figures in three cases. Two cases were cytologically diagnosed as malignant spindle cell neoplasm, not otherwise specified. The FNA of the recurrent tumor was diagnosed as consistent with the previous malignancy. The remaining case was interpreted as a pleomorphic adenoma with atypia. CONCLUSIONS: The cytologic features of myoepithelial carcinoma are diverse and may lack overt features of malignancy. Pathologists should be aware of this entity when evaluating cytologic specimen of salivary gland mass.