Radiology of Ewing's sarcoma: Intergroup Ewing's Sarcoma Study (IESS)

The Intergroup Ewing's Sarcoma Study 7299 patients represent a typical population of Ewing's sarcoma patients compared with those reported in the literature with regard to age, race, sex and distribution of lesions (7). The typical patient may be described as caucasian, in the first or second decade of life, and more likely male than female. The patient's tumor is most likely to arise in the pelvis or the long bones of the lower extremity (61.7%), and if in the long bones, it is most likely to be metadiaphyseal or diaphyseal in location (94.1%). Even so, Ewing's sarcoma may affect any bone primarily. Ewing's sarcoma presents with a myriad of roentgen appearances (8, 9). Although typically the lesion is medullary cavity based, metadiaphyseal in location and poorly marginated, with aggressive periosteal reaction and a large associated soft tissue mass, many patients with Ewing's sarcoma will have at least one atypical; i.e., uncommon or rare component to their lesion (27.2% in our series). The recognition of atypical Ewing's sarcoma is important because it may make earlier diagnosis possible and, thus, may contribute to improved survival for patients afflicted with this frequently deadly disease (10, 11).