[Case of immature teratoma of the testicle metastasizing as completely mature teratoma].

A case of immature teratoma of the testicle metastasizing as completely mature teratoma is presented. A 23-year-old man underwent right inguinal orchiectomy for an immature teratoma of the testicle on September 14, 1982. At retroperitoneal lymph node dissection, 12 lymph nodes were removed, all of which were negative for cancer. He was well until March 1983, when bloody sputum and left chest pain occurred. Since full lung tomography revealed two pulmonary nodules, he was treated with a course of VP-16 and three courses of vinblastine, bleomycin and CDDP. In September 1983, after completion of the combination chemo-therapy, the two pulmonary nodules were noticed to be slightly enlarging. A thoracotomy was scheduled to remove these nodules, since they were believed to be his only remaining tumors. Pathologic examination of the extirpated nodules disclosed completely benign teratoma. Mediastinal lymph nodes had no metastatic involvement histologically. It is our intention in this paper to emphasize, by means of several case reports, the frequently benign nature of these residual lesions and also to emphasize a recently recognized phenomenon--the apparent induction of benign teratomas by this intensive chemotherapy.