Oncocytic adenocarcinoma arising in Warthin's tumor.

Warthin's tumor (adenolymphoma) is a monomorphous adenoma of the salivary glands well characterized histologically. Its clinical evolution is almost invariably benign, the malignant change being extremely unusual. We present the case of a 67 year-old man with a right retromandibular tumor which has evolved over a two year period, with peripheral involvement of V, VI and VII cranial nerves on the same side, and direct invasion of intracranial structures. The biopsy revealed a classic adenolymphoma which shows foci of well differentiated adenocarcinoma. Transitional areas between benign and malignant epithelium were evident. In addition, histological findings support the hypothesis of the origin of adenolymphoma from epithelial ducts trapped in the regional lymphatic tissue.