Oncocytic mucoepidermoid carcinoma of the parotid gland: Report of a case with DNA ploidy analysis and review of the literature

A 44-year-old female presented with a painful mass in the left parotid glan d. Histologic examination revealed the characteristic picture of oncocytic mucoepidermoid carcinoma (OMEC) composed mainly of sheets of oncocytic cell s with uniform nuclei and eosinophilic cytoplasm, focally smaller epidermoi d cells surrounding poorly formed glandular spaces, and a few cystic struct ures lined by well-differentiated mucous cells with intracytoplasmic mucin. Immunohistochemical staining with antimitochondrial antibody showed granul ar cytoplasmic positivity in oncocytic cells. The resulting histogram for D NA ploidy analysis was of diploid type. OMEC of the parotid gland is a rece ntly described rare neoplasm. Only six cases have been previously reported in the literature. For an accurate approach in the management of patients, OMEC should be considered in the differential diagnosis of oncocytic lesion s of the parotid gland, most of which are benign.