MR imaging of parosteal osteosarcoma in two skeletally immature patients.

Parosteal osteogenic sarcoma is an unusual tumor in young children. It usually has a tendency to affect people with mature skeletons. The biological behavior of this tumor in children appears to be identical to that in adults, resulting in excellent prognosis after curative operative procedures, even if there is minimal extension to the bone marrow. Magnetic resonance imaging has a significant role in staging the tumor, as other imaging modalities are inferior in demonstrating early bone marrow involvement.