Primary dedifferentiated liposarcoma of the femur presenting with malignant fibrous histiocytoma: A case report and review of the literature.

In the current report a case of a 26-year-old male with a primary dedifferentiated liposarcoma of the femur accompanied by malignant fibrous histiocytoma is presented. The patient complained of a dull intermittent pain, for three months, along the anterolateral aspect of the right knee and was referred to Southwest Hospital (Chongqing, China) in May 2013. All of the radiographic findings, including radiography, magnetic resonance image and emission computed tomography (CT) supported the diagnosis of a primary malignant bone tumor. CT-guided biopsy results demonstrated blood clots and a small quantity of heterogeneous cells. Thus, a limb-salvage procedure, involving a wide resection and total knee endoprosthesis replacement, was performed in May 2012. The final pathological diagnosis was of a primary dedifferentiated liposarcoma of the femur and the dedifferentiated tissue was identified as malignant fibrous histiocytoma. On review of the literature, it was identified that primary intraosseous liposarcoma are a rare and malignant tumor of the skeletal system, with only a small number of cases reported in the English literature since 1980. To the best of our knowledge, a case of dedifferentiated liposarcoma has not previously been reported.