What is the Ewing family of tumors?
The Ewing family of tumors is a group of cancers that start in the bones or nearby soft tissue that share some common features. They can occur at any age, but these tumors are most common in early teenage years. There are 3 main types of Ewing tumors:
- Ewing sarcoma of bone
- Extraosseous Ewing tumor (EOE)
- Peripheral primitive neuroectodermal tumor (PPNET)
Ewing sarcoma of bone
Ewing sarcoma is the most common of the tumors in this family and is a type of bone tumor that occurs most often in children. It was first described by Dr. James Ewing in 1921, who found it was different from the more common bone tumor, osteosarcoma. Its cells looked different from osteosarcoma cells when viewed under a microscope. It was also more likely to respond to treatment with radiation therapy.
Extraosseous Ewing tumor (EOE)
Extraosseous Ewing tumors start in soft tissues around bones, but they look and act very much like Ewing sarcomas in bones. They are also known as extraskeletal Ewing sarcomas.
Peripheral primitive neuroectodermal tumor (PPNET)
This rare childhood cancer also starts in the bone or soft tissue and shares many features with Ewing tumor and EOE. Peripheral PNETs that start in the chest wall are known as Askin tumors.
(Peripheral PNETs are similar to, but not quite the same as, PNETs of the brain and spinal cord. For more information on those tumors, see our document called Brain and Spinal Cord Tumors in Children.)
Researchers have found that the cells that make up Ewing sarcoma, EOE, and PPNET are very similar. They tend to have the same DNA abnormalities and share similar proteins, which are rarely found in other types of cancers. That’s why it’s believed that these 3 cancers develop from the same type of normal cells in the body. There are slight differences among these tumors, but they are all treated in the same way.
Most Ewing tumors occur in the bones. The most common sites are the pelvis (hip bones), the chest wall (such as the ribs or shoulder blades), and the legs, mainly in the middle of the long bones. (In contrast, osteosarcoma usually occurs at the ends of the long bones, especially around the knees.) Extraosseous Ewing tumors can occur almost anywhere.
Most Ewing tumors occur in children and teens, but they can also occur in adults. This document focuses on Ewing tumors in children and teens, but most of the information here (including much of the treatment information) applies to Ewing tumors in adults as well.
Last Medical Review: 04/24/2012
Last Revised: 01/18/2013