Periosteal Ewing Sarcoma

Abstract

Most of the time, perioteal Ewing sarcoma is found in the diaphysis of the proximal extremities. It typically shows a monolamellar periosteal reaction with a Codman's triangle ( Figure 1A) over a subperiosteal soft tissue mass, which is sharply demarcated from the underlying cortical bone. Cortical scalloping and erosion are possible, but the tumor does not invade the cortical bone ( Figure 1B). Periosteal Ewing sarcoma doesn't show osseous or cartilaginous matrix calcifications.MRI is the best imaging modality to evaluate the tumor extent within the bone, the medullar cavity and the surrounding soft tissues. Medullary invasion is rare and should be suggested only when the marrow replacement is in continuity with the surface soft-tissue component. In our case there is a strict integrity of the cortex. FIGURE 1 Periosteal Ewing sarcoma: (A) right leg radiography, AP and lateral projections; (B) both legs MRI, SE T1 coronal postgadolinium.