Chondrosarcoma begins in the cartilage cells on the surface of a bone
or with it. The most common tumor sites are the pelvic bones, shoulder blades,
and the upper part of the arms and legs. It can occur at any age but seems to
favor middle-aged adults. It is found a little more often in males than
females.
Osteosarcoma
Osteosarcoma is also called osteogenic sarcoma is the most common
primary bone cancer. This cancer tends to show up in young adults (but can
occur at any age), and like chondrosarcoma, it appears slightly more often in
males than females. Osteosarcoma develops most commonly at the end of long
bones. About 80% of the osteosarcomas are found in the bones around and near
the knee, but can develop in any bone.
Ewing’s family of tumors
This cancer family is named after Dr. James Ewing, the doctor who discovered
the first of them in 1921. This bone cancer, called Ewing
tumor, is more common in young people than adults and was different from
its predecessors in that it could be treated with radiation therapy. In the
beginning, this tumor was seen only inside bones, but was later found in the
soft tissues outside the bone. Those are called extraosseous (outside the
bone) Ewing (EOE).
Primitive neuroectodermal tumor (PNET) is another child hood cancer
that shares similar features with the Ewing tumor. They
have similar proteins rarely found in other cancers and same DNA abnormalities,
and are believed to develop from the same type of cells in the body.
These 3 cancers are considered the Ewing family of
tumors (EFT). These tumors occur most often in the early teen years, but can
occur at any age. About 50% of Ewing family tumors begin
in the middle of the long bones of the legs; the next common sites are the
spine, ribs, and pelvis.