Ewing sarcoma

Ewing sarcoma is a tumor thought to derive from cells of the neural crest. Translocation t (11;22) or one of a series of related translocations is present in more than 95% of these sarcomas. Ninety percent of the tumors are first diagnosed in early age, usually in the second decade. Ewing sarcoma frequently presents as localized painful mass. Tumors of the long bones may present with pathologic fractures.