PERIOSTEAL EWING-SARCOMA

PURPOSE: To evaluate the imaging and histopathologic findings and clin ical course of patients with periosteal Ewing sarcoma (PES). MATERIALS AND METHODS: Conventional radiographs, computed tomographic (CT) scan s, and magnetic resonance (MR) images in 10 adolescents and one adult were evaluated for the extent and character of PES. RESULTS: Ten of 11 masses were in the proximal extremities and one in the fibula; nine w ere diaphyseal and two, metadiaphyseal. Radiographs and CT scans showe d a subperiosteal mass that did not invade the medullary cavity, was c ontiguous with and elevated the periosteum, and produced a Codman tria ngle and periosteal reaction. No PES exhibited osseous or cartilaginou s matrix calcifications. MR imaging and histopathologic examination he lped confirm the sparing of cancellous bone and the subperiosteal loca tion. CONCLUSION: PES differs from the more common medullary and soft- tissue Ewing sarcomas in location, marked male predominance, and lack of presenting metastases. Except for the absence of matrix calcificati ons, PES resembles other periosteal sarcomas in imaging characteristic s and a less aggressive clinical course.