[A Case of Retroperitoneal Liposarcoma That Required Three Times Surgical Resections during Four Years].

The patient was a 64-year-old man, who had undergone surgical resection for a right retroperitoneal giant tumor. The histopathological diagnosis was a well-differentiated liposarcoma. Two years and 4 months after the initial surgery, 3 recurrent lesions were found on the dorsal side of the colon hepatic flexure, and resection was performed. One year and 1 month after the secondary surgery, the tumor recurred again, and invaded the right abdominal wall and right transverse colon. Tumor was completely resected macroscopically. All resected tumors were well-differentiated liposarcoma. There have not been any signs of recurrence until 1 year and 6 months after the last operation. For retroperitoneal liposarcoma, complete surgical resection is the only established treatment, but the tumor often recurs. Aggressive resection against recurrent cases is known to contribute to life prognosis, but there is a possibility of the degeneration to a highly malignant dedifferentiated tumor while recurrence is repeated. Therefore, sufficient follow-up observation is needed.