Sarcomas are cancers that begin in the body's connective tissues. Sarcomas are often divided into two groups. One group is the bone cancers which begin in the hard part of the bone. The other group is the soft tissue sarcomas which start in the muscles, fat, fibrous tissue, blood vessels, nerves, or other supporting tissues of the body.
Ewing's sarcoma is a form of bone cancer. It is the second most common malignant bone tumor of children and young adults and accounts for about l% of all childhood tumors. About 90% of patients with Ewing's sarcoma are under the age of 30 and about 70% are under 20. Frequent sites include the bones of the leg, upper arm, pelvis, ribs, vertebrae and shoulder blade. It is a fast-growing cancer that easily spreads to the lungs or to other bones.