Treated Ewing sarcoma: radiographic appearance in response, recurrence, and new primaries.

Healing of Ewing sarcoma after therapy has a predictable radiographic appearance, eventually stabilizing and remaining constant in appearance. This study is based on 35 patients in whom adequate follow-up radiographs were available. The expected sequence was evident in 21 patients. Complete healing was evident in about 1 year. Failure to heal as expected or lytic change in healed bone indicated recurrent or refractory disease in 11 patients who developed distant metastases or clinical signs of recrudescence at the primary site. This complication was evident within months to 2 years of the initial treatment. In three patients, development of a new, primary, osteogenic sarcoma was heralded by disorganized tumor new bone in an osteoid matrix, evident only after several years of stability. These new osseous malignancies are probably treatment-related.