Periosteal Ewing sarcoma.

Abstract

To evaluate the imaging and histopathologic findings and clinical course of patients with periosteal Ewing sarcoma (PES). Conventional radiographs, computed tomographic (CT) scans, and magnetic resonance (MR) images in 10 adolescents and one adult were evaluated for the extent and character of PES. Ten of 11 masses were in the proximal extremities and one in the fibula; nine were diaphyseal and two, metadiaphyseal. Radiographs and CT scans showed a subperiosteal mass that did not invade the medullary cavity, was contiguous with and elevated the periosteum, and produced a Codman triangle and periosteal reaction. No PES exhibited osseous or cartilaginous matrix calcifications. MR imaging and histopathologic examination helped confirm the sparing of cancellous bone and the subperiosteal location. 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 calcifications, PES resembles other periosteal sarcomas in imaging characteristics and a less aggressive clinical course.