[RETROPERITONEAL LIPOSARCOMA WITH MULTIPLE RECURRENCE OF LUNG METASTASES TREATED BY MULTIMODAL THERAPY CENTERING ON THE OPERATION: A CASE REPORT].

A 34-year-old man presented with scrotal pain and slight fever. The scrotal pain was improved by the treatment of antibiotics, but the slight fever remained and an abdominal protuberance appeared. Computed tomography showed a 22 cm abdominal tumor with lipid density. He was then referred to our hospital. He was diagnosed as retroperitoneal liposarcoma and a surgical resection was performed for retroperitoneal tumor and surrounding organs. Histopathological diagnosis was dedifferentiated liposarcoma. 3 months after surgery, a PET/CT scan showed multiple lung metastases. We treated the patient with AI therapy by doxorubicin and ifosfamide. After 6 courses were performed, a complete response was achieved. 30months after the initial surgery, a PET/CT scan showed there was just one metastasis which was in the left lung. Thoracoscopic lung tumor resection was performed. Histopathological diagnosis was metastatic dedifferentiated liposarcoma. As adjuvant therapy, we treated with IE therapy by ifosfamide and VP-16. 3 courses were performed. 3 years and 6 months after the first surgery, he has had no recurrence up to the present day.