Epiphyseal ewing sarcoma: first reported case with molecular confirmation

Ewing sarcoma is the second most common pediatric malignant bone neoplasm after osteosarcoma. Ewing sarcoma comprises "small, round, blue-cell" tumors thought to arise from neural crest cells. The authors report the case of a 14-year-old boy that presented with a nonpainful circumscribed lesion. The radiographs showed a lytic lesion at the tibial epiphysis with a large soft tissue mass, best depicted in the magnetic resonance imaging scan that suggested an aggressive lesion. A needle biopsy of the lesion was performed. The diagnosis of Ewing sarcoma was made based on microscopic, immunohistochemical, polymerase chain reaction, and fluorescence in situ hybridization. This is the third case report about a primary epiphyseal Ewing sarcoma and the fist one with molecular confirmation.