Malignant Fibrous Tumors of Bone

Malignant Fibrous Tumors of Bone (MFT) are much rarer than the bone and cartilage forming malignant tumors. The two major types include the fibrosarcoma and malignant fibrous histiocytoma (MFH). They can be grouped together and therefore considered the same in bone.

MFT of Bone usually occurs secondary to other illness such as Paget's disease, giant cell tumor, fibrous displasia, osteomyelitis or bones that have had radiation therapy. These tumors occur in both sexes and in all age groups but are found most often between the ages of 40-60. They are usually located in the long bones of the lower extremities, especially the distal femur and proximal tibia. These lesions are very destructive, thus pathologic fractures are common. X-rays show the destructive (lytic), poorly defined lesions, usually with breakthrough into the cortex causing a soft tissue mass. Low-grade tumors have a more well-defined margin than the high-grade tumors. The appearance of the tissue cells (malignant fibroblastic stroma and collagen fibers) varies with the grade or degree of tumor aggressiveness. Malignant bone and cartilage tissue are not found in this lesion. Treatment is mainly wide surgical resections. The treatment and outcomes are very similar to an aggressive osteosarcoma. Radiation may have little effect but are sometimes employed in recurrent lesions.