Ewing sarcoma can occur anytime during childhood and young adulthood. But it usually develops during puberty, when bones are growing rapidly. It is 10 times as common in Caucasian children as in African American, African, and Asian children.
The tumor may start anywhere in the body. Most often, it starts in the long bones of the arms and legs, the pelvis, or the chest. It can also develop in the skull or the flat bones of the trunk.
The tumor often spreads (metastasizes) to the lungs and other bones. At the time of diagnosis, spread is seen in about one-third of children with Ewing sarcoma.
In rare cases, Ewing sarcoma occurs in adults.