Yolk sac carcinoma.

Yolk sac carcinoma is an uncommon neoplasm which has appeared under a variety of names. It has been reported not only in gonadal sites but also in the mediastinum, pineal body, and sacral areas. The typical histologic appearance of this tumor and the variety of locations are demonstrated by four case reports. A 57-year-old patient with an ovarian tumor is thought to be the oldest patient reported to date.