Oncocytic neoplasms of salivary glands: a report of fifteen cases including two malignant oncocytomas.

Fifteen oncocytic (oxyphilic granular cell) neoplasms of the salivary glands collected from three large university medical centers are presented. The histologic and ultrastructural criteria that characterize oncocytes are presented and electron micrographs of two of our cases are discussed. Included in the series are 10 benign oncocytomas, two malignant oncocytomas and three benign, oncocytic pleomorphic adenomas. The clinical and pathologic features of benign oncocytomas are reviewed, with special attention to the variety of gross and microscopic changes present. The literature on malignant oncocytomas is critically reviewed, diagnostic criteria are evaluated, and a unique case is discussed in detail. Reference is made to a group of neoplasms that we designate as benign locally aggressive oncocytomas. The problem of differential diagnosis between oncocytoma and bening, oncocytic pleomorphic adenoma is considered.