Ewing's Sarcoma family of tumors

The terms 'Ewing's sarcoma', 'peripheral primitive neuroectodermal tumor (PNET)', and 'malignant small cell tumor of the thoracopulmonary region' (Askin tumor) are currently regarded as manifestations of a single neoplastic entity with underlying common phenotypic and molecular features. These tumors are now grouped under the general eponym Ewing's sarcoma family of tumors (ESFT) and are characterized by non-random translocations involving the EWS gene and one of several members of the ETS family of transcription factors. The Ewing's sarcoma family of tumors is the second most common malignant neoplasm of bone arising in children and adolescents, with osteosarcoma being the most common. In the United States, the annual incidence rate of ESFT in the general population is three per million. Boys are more commonly affected than girls, and the disease exhibits marked predilection for whites and is particularly rare among black people. Most patients are between the ages of 5 and 20 years at the time of diagnosis (median, 14 years), and the disease is rare in individuals older than 40 and younger than 5 years. There is no evidence that ESFT is associated with any familial predisposition syndrome or environmental factors. Several studies have demonstrated an increased cumulative risk of secondary cancers following therapy for ESFT, with radiation-induced osteosarcoma and therapy-related acute myeloid leukemia being the most frequent. Conversely, the occurrence of ESFT as a second neoplasm after therapy for other tumors is rare.