[A case of retroperitoneal tumor successfully resected thanks to effective chemotherapy]

We reported a case of retroperitoneal immature teratoma with embryonal carcinoma. First, pathological diagnosis of sarcoma was made by fine needle aspiration, then secondary pathological diagnosis of suspected malignant schwannoma was made by a partial resection. The final pathological diagnosis by operation was immature teratoma with embryonal carcinoma. The preoperative diagnosis was difficult in this case, and the tumor had grown too large after partial resection to surgically resect. The effective chemotherapy reduced this tumor enough to allow successful resection. Although the prognosis of immature retroperitoneal teratoma is poor, this case has survived 10 years after operation without metastasis and recurrence.