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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, the most common of the tumors in this family,
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. It is more likely to
respond to radiation, and its cells look different when viewed under a
microscope.
Extraosseous Ewing tumor
Extraosseous Ewing (EOE) 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
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 the separate American Cancer Society document, 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 have the same DNA
abnormalities and share similar proteins, which are rarely found in
other types of cancers. Because of this, it is believed that these 3
cancers develop from the same type of normal cells in the body.
Although there are slight differences among these tumors, they are all
treated in the same way.
Most Ewing tumors occur in the bones. The most common sites
are the pelvis, 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.
Last Medical Review: 08/20/2009
Last Revised: 08/20/2009
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