Primary yolk-sac (endodermal sinus) tumor of the prostate.

A primary yolk-sac (endodermal sinus) tumor of the prostate occurring in a 51-year-old man is described, and the difficulties associated with classification of this tumor are discussed. Yolk-sac tumors have been reported to arise in several extragonadal sites, but to our knowledge this is the first documented case of a germinal cell tumor occurring the the prostate. This tumor in extragonadal sites carries a grave prognosis. Despite radical surgery, radiotherapy, and chemotherapy, this patient died 10 months after the tumor was diagnosed.