Mucoepidermoid carcinoma of the lacrimal gland. Report of a case with oncocytic features arising in a patient with chronic dacryops.

A 62-year-old woman had recrudescence of growth of a lacrimal gland fossa cystic mass present for more than 40 years. Results of histopathologic examination of the excised specimen showed infiltrating nests of epidermoid and mucin-producing cells, consistent with a mucoepidermoid carcinoma. Also present were numerous large oncocytic cells partially lining the lumens of the multiloculated cyst and penetrating the adjacent stroma. To the authors' knowledge, this is the first reported case of mucoepidermoid carcinoma with prominent oncocytic features arising in a previously documented chronic cystic lesion of the lacrimal gland. Because of the population of oncocytes (a metaplastic phenomenon encountered in ductular epithelial cells) among the cells lining the cyst, the authors conclude that the carcinoma arose from a long-standing dacryops. This conclusion was also supported by the electron microscopic demonstration of duct-type secretory granules within the mitochondria-rich oncocytes.