Myoepithelial carcinoma of the parotid gland.

Myoepithelial carcinomas exhibit a wide spectrum of cytomorphologic features and diverse clinical outcomes. As a result of their morphologic heterogeneity, they can be confused easily with many tumours. Herein we report the morphological features of myoepithelial carcinoma in a 74-year-old female clinically presenting with a parotid mass. FNAB revealed hypercellular, three-dimensional clusters with considerable overlapping and crowding of pleomorphic neoplastic cells which consisted predominantly of spindle cells, with oval to elongated to spindle shaped nuclei showing considerable variation in size. The excised tumour was solid, with cells arranged in trabeculae, nests and cords. Tumour cells were mixed epithelioid and spindle with eosinophilic or clear cytoplasm, with eccentric nuclei and prominent nuclei. Neoplastic cells were found in blood vessels, in the skin and facial nerve. Tumour cells were immunopositive for PAS, PAS-D, S-100 protein, GFAP, P63, CK5/ CK6, CK7, and CK14. This case illustrates that cytological features in FNAB generally reflect the histology. FNAB was able to confirm the diagnosis and guide patient management.