There is a classic sunburst pattern of new bone formation, whose sclerotic trabeculae extend out perpendicular to the long axis of the femur. The periosteum is elevated at the proximal portion of the lesion. These are the classic Codman's trangles often assocated with an osteosarcoma. The MRI studies in the middle and the right show the intrameduallary extent of the lesion. We see the tissue extent of the lesions as a hyperintense signal which corresponds to the sunburst trabeculae on plain film.
Osteogenic sarcoma is one of the most common types of primary malignant bone tumors.
There are several distinct types, each with its own distinct clinical, radiographic and histological characteristics. All types have in common that the osteoid and bone matrix of the lesion are formed by malignant cells. Radiological findings include medullary and cortical bone destruction, and an aggressive periosteal reaction. A soft tissue mass and tumor either within the destructive lesion or at its periphery, as well as in the soft tissue mass, can often be seen. The periosteal responses most commonly seen are the sunburst type and Codman's triangle, though the lamellated onion skin type may also be seen.