A 56-year-old woman was referred to our hospital with complaints of appetite loss and abdominal distension. Enhanced abdominal computed tomography revealed a giant retroperitoneal tumor. We performed en bloc tumor resection. The histological diagnosis was of a dedifferentiated liposarcoma. One year after the initial surgery, 2 tumors were detected around the pancreas using computed tomography. We made a diagnosis of recurrent retroperitoneal liposarcoma and attempted surgical removal of the tumors. However, 1 of the tumors firmly adhered to the pancreas and duodenum; thus, we performed subtotal stomach-preserving pancreaticoduodenectomy to remove the tumors. The histological diagnosis was the same as that obtained during the initial surgery: a dedifferentiated liposarcoma. The patient remains alive and well with no evidence of disease 2 years after the initial surgery.