Oncocytoma of the caruncle.

The oncocytoma (oxyphil adenoma) is an uncommon tumor composed of transformed epithelial cells of the ducts of salivary glands and other organs. In two men, 66 and 75 years old, oncocytomas originated in the caruncle where they assumed rather characteristic features. The caruncular oncocytomas clinically appeared to be cystic. Light microscopy showed that the tumor cells (oncocytes) had eosinophilic granular cytoplasm; electron microscopy demonstrated that the cytoplasm contained densely packed abnormal mitochondria.