A Case of Resected Double Cancer Involving a Retroperitoneal Undifferentiated Pleomorphic Sarcoma and an Ascending Colon Cancer

Abstract

We report a rare case of double cancer involving a retroperitoneal undifferentiated pleomorphic sarcoma (UPS) and an ascending colon carcinoma. A 75-year-old male was admitted to our hospital because of a high fever and painful abdominal mass in the right lower quadrant. An enhanced CT scan and colonoscopy revealed an ascending colon carcinoma with perforation and an abscess. In addition, a 4.7-cm retroperitoneal tumor was found adjacent to the third portion of the duodenum and a duodenal submucosal tumor was suspected. A right hemicolectomy and retroperitoneal tumor resection were performed simultaneously. Practically, the retroperitoneal tumor was discontinuous to the duodenum and located just ventral to the abdominal aorta at the level of the left renal vein. The drainage veins of the tumor ran directly into the inferior vena cava. The major axis of the retroperitoneal tumor was 5.3 cm. Histologically, the retroperitoneal tumor was diagnosed as a UPS. Adjuvant radiotherapy was performed on the tumor bed of the retroperitoneal UPS. The patient is alive with no signs of recurrence 18 months after the surgery.