Ewing sarcoma is a cancer that occurs primarily in the bone or
soft tissue. Ewing sarcoma can occur in any bone, but most often
it is found in the long bones such as the femur (thigh), tibia
(shin), or humerus (upper arm). It can involve the muscle and
the soft tissues around the tumor site as well. Ewing sarcoma
cells can also spread (metastasize) to other areas of the body
including the bone marrow, lungs, kidneys, heart, adrenal gland,
and other soft tissues. Ewing sarcoma accounts for about 2
percent to 3 percent of childhood cancers. About 250 children
and adolescents will be diagnosed with Ewing sarcoma in the US
in 2008. It is the second most common malignant bone tumor in
children and adolescents. Ewing sarcoma most often occurs in
children between the ages of ten and 20. More males are affected
than females. The exact cause of Ewing sarcoma is not fully
understood. There seems to be no known risk factors or
prevention measures available. However, researchers have
discovered chromosomal changes in a c