Oncocytic variant of mucoepidermoid carcinoma: a diagnostic challenge for the pathologist.

Oncocytic mucoepidermoid carcinoma of the salivary gland is rare. We report a 48-year-old man who presented with a slowly growing right parotid mass. A preoperative fine needle aspiration showed exclusively oncocytic cells and cellular debris. A first diagnosis of Warthin tumor or myoepithelioma was made. The patient underwent a superficial parotidectomy, and her postoperative course was uneventful. Histologically, the tumor was composed of solid nests and cystic gland containing clear mucoid material, lined predominantly with oncocytes and few mucous goblet cells. A final diagnosis of oncocytic variant of mucoepidermoid low-grade carcinoma was made. The recognition of this variant is important, because may be easy confused with most frequent benign tumor with oncocytic cells; in this case a complete surgical excision and long-term clinical follow-up are an adequate management.