Late development of a malignant fibrous histiocytoma at the site of a giant cell tumor

A case of late development of a high grade malignant fibrous histiocytoma at the site of a previously surgically treated giant cell tumor is reported. The patient initially was treated for a benign giant cell tumor of the lateral condyle of the distal femur by curettage, implant of auto- and allograft bone, but no radiation. Eighteen years later, he noted progressively increasing pain and disability. Radiographs showed some change, but magnetic resonance imaging clearly disclosed a tumor risking at the site and extending outside the bone. After chemotherapy, the tumor was resected and histologically showed no evidence of a recurrent giant cell tumor, only a high grade malignant fibrous histiocytoma.