FROM THE ARCHIVES OF THE AFIP - THE MANY FACES OF OSTEOSARCOMA

Osteosarcoma is the most common primary malignant tumor of bone in ado lescents and young adults. It accounts for approximately 15% of all pr imary bone tumors confirmed at biopsy, There are numerous types of pri mary osteosarcoma, including intramedullary (high grade, telangiectati c, low grade, small cell, osteosarcomatosis, and gnathic), surface (in tracortical, parosteal, periosteal, and high-grade surface), and extra skeletal, Osteosarcoma may also occur as a secondary lesion in associa tion with underlying benign conditions, The identification of osteoid matrix formation and aggressive characteristics usually allows prospec tive radiologic diagnosis of osteosarcoma, As with all bone tumors, di fferential diagnosis is best assessed with radiographs, whereas stagin g is performed with computed tomography or magnetic resonance imaging, Understanding and recognition of the variable appearances of the diff erent varieties of osteosarcoma allow improved patient assessment and are vital for optimal clinical management including diagnosis, biopsy, staging, treatment, and follow-up.