Oncocytic mucoepidermoid carcinoma of the salivary glands

Two parotid mucoepidermoid carcinomas with predominant oncocytic features w ere initially assessed on frozen section. Because of extensive oncocytic ch ange, it was inferred that the lesions were most likely benign. Permanent s ections revealed low-grade mucoepidermoid carcinoma with prominent oncocyti c change (in more than 75% of the neoplasms) in both cases. Review of 48 ad ditional consecutive cases of mucoepidermoid carcinoma of the salivary glan ds revealed prominent oncocytic change (accounting for 60% of the neoplasm) in one high-grade lesion. Phosphotungstic acid-hematoxylin stains revealed strong granular cytoplasmic staining in the oncocytic elements; immunohist ochemical stains for antimitochondrial antibodies also showed intense immun oreactivity in these cells. Oncocytic change is not typically a prominent f eature of mucoepidermoid carcinoma of the salivary glands, and to our knowl edge, only three such cases have been reported previously.(16,22.39) Becaus e most salivary gland lesions with oncocytic change are benign, it is impor tant to distinguish mucoepidermoid carcinoma from other entities that may s how prominent oncocytic change. We report three additional examples of this rare lesion, two low-grade tumors and one high-grade tumor, and review our experience with oncocytic change in mucoepidermoid carcinoma of the saliva ry glands.