The case of a 63 year-old man with a giant scrotal and retroperitoneal tumor is herein reported. The initial symptoms began in the scrotum and subsequent abdominal distention resulted in discomfort 2 years later. The intraabdominal organs were under pressure because of the bulky mass, and the patient had dyspnea. Ultrasonograpy, computed tomography, and fine needle aspiration biopsy investigations all revealed a retroperitoneal tumor suspected to be liposarcoma. At operation, a tumor weighing 42 kg was excised. Respiratory support was provided in the early postoperative period. The histopathological diagnosis was myxoid liposarcoma. The patient was discharged from the hospital 14 days after the operation and was scheduled to undergo radiotherapy.