Osteosarcoma and its variants.

Osteosarcoma is the most common primary malignant tumor of bone. The variability of this tumor and its histologic variants in presentation, location, and biologic behavior has an influence on the prognosis and determines treatment options. Despite improvements in both survival and function due to limb salvage techniques and adjuvant chemotherapy, osteosarcoma continues to be a major challenge for the medical and surgical oncologist.