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[Case of testicular cancer with malignant transformation in the residual retroperitoneal mature teratoma 8 years after the initial chemotherapy].

We here report a case of the gradual maturation of teratoma during 8 years after the initial chemotherapy. A 21-year-old man was diagnosed as having a left testicular tumor with retroperitoneal lymph node metastasis around the left renal artery in 1988 and high inguinal orchiectomy was carried out. Histological examination revealed a mixed germ cell tumor composed of immature teratoma, embryonal carcinoma, and seminoma. He received four courses of PVB chemotherapy for his bulky lymph node metastasis. After normalization of the alpha-fetoprotein level, retroperitoneal lymph node dissection (RPLND) was performed. However, the nodes could not be dissected completely because of severe adhesions to the aorta. Histological examination revealed massive necrosis and immature teratoma. One cause of combination chemotherapy with cisplatin and etoposide was given following the surgery. In 1991, enlargement of the residual lymph nodes around the left renal artery was detected by CT scanning. Since both PVB chemotherapy and the combination of cisplatin with etoposide did not achieve remission, RPLND was performed again. Histological examination revealed a mature teratoma which was far more differentiated than that resected in 1988. In 1996, several enlarged para-aortic lymph nodes were found without the elevation of tumor makers, and en-bloc RPLND was performed. Microscopically, mature teratoma was observed in almost all specimens and, unexpectedly, adenocarcinoma was also observed in enteric elements of the mature teratoma. We concluded that we could not evaluate the malignant biological characteristics of teratoma from its maturation level and residual retroperitoneal teratomas should be as completely resected as possible.