Benign fibrous histiocytoma of the femur: Review of three cases

Objective. Benign fibrous histiocytoma is a tumor with histologic features similar to those of xanthofibromas, which include fibrous cortical defects and nonossifying fibromas, but with different clinical features. This study investigated the findings of benign fibrous histiocytoma on various imaging modalities. It emphasized the importance of clinical and imaging features as well as histologic findings in establishing the diagnosis. Design. We reviewed three cases of benign fibrous histiocytoma of the femur that had been diagnosed histologically as (fibro)xanthoma during a retrospective analysis of 187 primary benign and malignant bone lesions. Patients. All the patients were middle-aged women with various knee complaints. Results and conclusions. Radiologically, the lesions were all lytic with well-defined geographic margins and sclerotic rims. The tumors arose within the medullary cavity in the distal metaphysis of the femur and involved the epiphysis. CT showed lytic destruction with well-defined marginal sclerosis. T1-weighted MR images showed that the lesions had predominantly the same signal intensity as that of skeletal muscle. The lesions were hypovascular on angiography. Bone scintigraphy showed moderately increased uptake. It was concluded that multiple images as well as clinical features can be useful in differentiating benign fibrous histiocytoma from fibroxanthoma, giant cell tumor, and other fibrohistiocytic tumors of bone.