A case of myoepithelioma in the parotid gland

Myoepithelioma is a rare tumor accounting for less than 1% of all salivary gland tumors. We report a case of plasmacytoid myoepithelioma arising in the parotid gland. A 66-year-old woman with a painless swelling of the left parotid gland was referred to our hospital in October, 2003. Computed tomographic examination revealed a well circumscribed mass contrasted by heterogeneity. On magnetic resonance imaging, T2-weighted images revealed high signal intensity mass, measuring 2.5 × 1.5 × 3.2 cm. Needling aspiration diagnosis was negative. The tumor was surgically removed under a clinical diagnosis of a benign tumor. Pathologically, the tumor was diagnosed as myoepithelioma (plasmacytoid cell type). Immunohistochemically, the tumor was stained with S-100 protein, cytokeratin and α smooth muscle actin. There was no evidence of recurrence 9 months after the surgery.