Extragonadal germ cell tumor of the prostate associated with Klinefelter's syndrome. 
We report on a case of extragonadal germ cell tumor of the prostate associated with Klinefelter's syndrome.  The patient was a 33-year-old man.  A transrectal prostate biopsy suggested combined germ cell tumor (yolk sac tumor + teratoma).  Because there was no tumor except from the prostate, we considered this case to be a primary extragonadal germ cell tumor of the prostate.  The prostate tumor responded to systemic chemotherapy with cisplatin, vinblastine and bleomycin and elevated lactate dehydrogenase and alpha-fetoprotein levels normalized.  In addition to chemotherapy, the patient also underwent radiation therapy.  The patient has survived for approximately 4 years since the diagnosis.