Retroperitoneal dedifferentiated liposarcoma with rare heterologous low-grade osteosarcoma: A case report

Dedifferentiated liposarcoma is a high-grade entity developed from a preexisting or recurrent well-differentiated liposarcoma, and rarely, it may contain divergent differentiation. We presented the case of a 39-year-old woman with retroperitoneal dedifferentiated liposarcoma with heterologous low-grade osteosarcoma, possessing a special pattern of tumoral calcification.