This learning module describes the incidence and pathogenesis of bone tumors of the foot.
This learning module describes the most common malignant bone tumors of the foot, explains the possible causes for malignant bone tumors of the foot, and outlines the general methods used to treat these tumors.
Tumors of the foot and ankle represent a unique subset of all bone and soft tissue tumors, showing variance in type, location, age, prognosis and treatment from tumors in the rest of the musculoskeletal system. Bone tumors in this location are more common in males by a ratio of 4:3. Most are cartilagenous or cystic, with a minority of tumors being osteoblastic.
Chondrosarcoma and osteosarcoma are the most common bone sarcomas in the foot and ankle. The proportion of tumors that exhibit malignant behavior is around 5%, whereas 20% of mass forming lesions may be malignant. Malignancies appear to comprise a larger proportion of tumors in the foot and ankle than elsewhere in the body. However, patient survival is significantly better in distal lower extremity tumors than for sarcomas in other musculoskeletal sites.
Bone and soft tissue sarcomas are thought to be caused by a series of alterations in the structure or expression of the genetic material of the mesenchymal cell of origin. A few are caused by exposure to radiation or by an underlying genetic abnormality such as the RB-1 gene in hereditary retinoblastoma, or the p53 gene in Li-Fraumeni syndrome.
Treatment of sarcomas requires resection with a wide margin, plus adjuvant chemotherapy and/or radiotherapy depending on tumor type. In the foot and ankle, adequate resection with a wide margin may require partial or complete amputation of the part. Limb salvage following removal of tumors in the foot and ankle is complicated by the loads on the skeletal elements and the generally scant soft tissue coverage. The ultimate goal of treatment is elimination of the tumor and restoration of the patient's long-term mobility and function.
