Oncocytic pleomorphic adenoma of the parotid gland.

A rare case of salivary gland pleomorphic adenoma, in which the majority of cells were oncocytic, is reported. The patient, a 53-year-old man, presented with a parotid gland mass that was otherwise asymptomatic. Surgical treatment consisted of a superficial parotid lobectomy. The specimen was prepared in standard fashion and studied by light and electron microscopy. The microscopic features were characteristic of salivary gland pleomorphic adenomas, however, both epithelial and "mesenchymal" elements were oncocytic. Such changes may occur focally in pleomorphic adenomas, but we were unable to find documentation of a wholly oncocytic variant in a review of the medical literature. From our clinical data and previous reports of pleomorphic adenomas with focal oncocytosis, it is concluded that such changes likely do not alter prognosis in affected patients. The possible significance of this lesion in regard to the histogenesis of salivary gland pleomorphic adenomas is discussed.