A case of myxofibrosarcoma of the retroperitoneum

A 62-year-old man was admitted because of left upper abdominal pain and a growing mass in his left abdomen. Abdominal CT and MRI revealed a 150 mm×110 mm discrete mass, pressing the left kidney. Laparotomy was performed under a preoperative diagnosis of malignant retroperitoneal tumor. Operative findings showed that the tumor adhered to the left kidney and the descending colon. Therefore combined resection of the tumor and left kidney and part of the descending colon was performed. The histopathological diagnosis was myxofibrosarcoma originated in the retroperitoneum. Thirty-seven months later, recurrence in the mesentery was diagnosed, and the recurrent tumor had grown rapidly. We performed tumor resection, however, the second recurrence in the peritoneum was diagnosed 4 months postoperatively. Six recurrent tumors were found in the peritoneum and all were resected. He is undergoing adjuvant chemotherapy with MAID (MESNA+ADM+IFM+DTIC) since the last operation and is without recurrence 4 months after the last operation. The majority of myxofibrosarcomas arises in the limbs. We report rare cases of myxofibrosarcoma that originated in the retroperitoneum.