Dedifferentiated liposarcoma (DDL) with unusual forms of tissue differentiation is rarely seen and varies in presentation. These tumors often arise in the retroperitoneal area, where they tend to grow silently to a large size, appear late, and have a poor prognosis. We describe a rare case of an elderly male who initially presented with what appeared to be an inguinal hernia. Further evaluation revealed a large abdominal mass. CT imaging showed that the tumor occupied most of the left side of the abdomen, with blurred boundaries between it and the left kidney and spleen. During surgery, a large retroperitoneal mass was found pushing the colon and ureter across the midline. The tumor was removed, and the left kidney was preserved. The specimen contained multiple tumor fragments ranging from 15 to 40 cm in size, weighing over 25 kg in total. Histological analysis revealed well-differentiated liposarcoma alongside two distinct types of heterologous differentiation—areas resembling both chondrosarcoma and osteosarcoma. Based on these findings, the final diagnosis was a recurrent, multifocal, giant retroperitoneal DDL with dual heterologous differentiation. Despite the tumor’s recurrence and complex features, detailed imaging, complete surgical resection, and thorough pathological evaluation were crucial in confirming the diagnosis.
