Primary skeletal neoplasms: osteosarcoma and ewing sarcoma.

The care for children and adolescents with malignant bone tumors such as osteosarcoma and Ewing sarcoma will be improved by the magnetic resonance imager that can recognize the tumor early in its course and can stage it correctly for proper chemotherapy and local control. This can be accomplished by attention to the proper magnetic resonance imaging technique, recognition of the magnetic resonance appearance, and knowledge of the prognostic factors at diagnosis. Determination of response on follow-up static and dynamic contrast-enhanced magnetic resonance imaging and knowledge of optimal methods to determine recurrent tumor will improve the outcome for these children.