What Is Osteosarcoma?

Osteosarcoma (also called osteogenic sarcoma) is a type of bone cancer that develops in the osteoblast cells that form the outer covering of bone. It occurs most often in children, adolescents, and young adults. Learn more about childhood osteosarcoma.

Osteosarcoma most commonly occurs in the long bones around the knee. Other sites for osteosarcoma include the upper leg, or thighbone, the lower leg, upper arm bone, or any bone in the body, including those in the pelvis, shoulder, and skull.

Osteosarcoma may metastasize, or spread, into nearby tissues, such as tendons or muscles. It may also metastasize through the bloodstream to other organs or bones in the body.

The exact cause of osteosarcoma is not known, but may be due to DNA mutations—either inherited or acquired after birth.