Periosteal Ewing's sarcoma: radiological imaging and histological features.

Periosteal Ewing's sarcoma is very rare. In this report, we describe three cases of periosteal Ewing's sarcoma, illustrating the principal clinical, radiographic, and histologic features. The patients were aged 15, 16, and 20 years old, with an average of 17 years. The tumor occurred in the humerus in two and in the femur in one. Plain radiography showed a laminated periosteal reaction with a Codman's triangle over a subperiosteal soft-tissue mass or saucerization. The unusual site of Ewing's sarcoma was clearly visualized by computed tomography (CT) and magnetic resonance imaging (MRI) and confirmed by histological examination. Chemotherapy and/or irradiation was employed before and after wide excision. The patients have survived an average of 6 years after the primary surgery.