In 1921, James Ewing, MD, described a bone tumor that, unlike the common bone tumor, osteosarcoma, could be treated with radiation. This newly identified tumor became known as Ewing’s tumor. At first, this tumor was only seen in bones. Soon, the same type of tumor was detected in the soft tissues and named extraosseous Ewing’s (EOE).
Another childhood cancer, primitive neuroectodermal tumor (PNET), shares many features with Ewing’s tumor. PNETs are rare cancers found in soft tissue and bone. It was questioned if Ewing’s, EOE, and PNET were in the same family, and now it’s been shown that PNET and Ewing’s both arise from the same primitive cell. The tumors are now called the Ewing's family of tumors (EFT) or a tumor of the Ewing’s family (TEF). Of the tumors in this family, Ewing’s tumor of bone represent 87 percent, while EOE (at eight percent) and PNET (at five percent) are much rarer.
TEF can occur at any age but are most common in the early teen-age years. Most occur in the middle of long bones of the legs or arms, unlike osteosarcoma, which usually occurs at the ends of the bones. Tumors can also occur in the pelvic bones or in the chest near the ribs.