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 cancer that can be found in both the bone or in the soft tissue, depending on the type. It is the second most common malignant bone tumor of children and young adults and accounts for about 2 to 3 percent of all childhood tumors. Nearly half of all cases are in individuals 10-20 years of age. Frequent sites include the bones of the leg, upper arm, pelvis, ribs, spine and pelvis. It is a fast-growing cancer that easily spreads to the lungs or to other bones.