Ewing Family of Tumors (Ewing Sarcoma/Peripheral Neuroectodermal Tumor)

Extraskeletal Ewing Sarcoma (ES) and Peripheral Primitive Neuroectodermal Tumor (PNET) are considered to represent two ends of the same spectrum, and hence appropriately named Ewing Family of Tumors (EFT). These tumors are characterized by EWSR1 gene rearrangement, most often as a consequence of a reciprocal t(11;22)(q24;q12). There is no clinical or therapeutic value in attempting to separate ES and PNET, and there is no correlation between the degree of neuroectodermal differentiation and prognosis.