Dedifferentiated liposarcoma (DDLPS) has been defined as a tumor composed of well-differentiated liposarcoma associated with a nonlipogenic undifferentiated sarcoma and is genetically characterized by a 12q13-15 amplicon with MDM2 amplification. Some peripheral (extremities, trunk wall, head/neck) undifferentiated pleomorphic sarcomas (UPS) without areas of well-differentiated liposarcoma prese...