Bone Cancers
Bone cancer is a malignant (cancerous) tumor of the bone that destroys normal bone tissue. Not all bone tumors are malignant. In fact, benign (noncancerous) bone tumors are more common than malignant ones. Both malignant and benign bone tumors may grow and compress healthy bone tissue, but benign tumors do not spread, do not destroy bone tissue, and are rarely a threat to life.

Malignant tumors that begin in bone tissue are called primary bone cancer. Cancer that metastasizes (spreads) to the bones from other parts of the body, such as the breast, lung, or prostate, is called metastatic cancer, and is named for the organ or tissue in which it began. Primary bone cancer is far less common than cancer that spreads to the bones.

Different types of primary bone cancer
Osteosarcoma, which arises from osteoid tissue in the bone. This tumor occurs most often in the knee and upper arm.

Chondrosarcoma, which begins in cartilaginous tissue. Cartilage pads the ends of bones and lines the joints. Chondrosarcoma occurs most often in the pelvis (located between the hip bones), upper leg, and shoulder. Sometimes a chondrosarcoma contains cancerous bone cells. In that case, doctors classify the tumor as an osteosarcoma.

The Ewing Sarcoma Family of Tumors (ESFTs), which usually occur in bone but may also arise in soft tissue (muscle, fat, fibrous tissue, blood vessels, or other supporting tissue). Scientists think that ESFTs arise from elements of primitive nerve tissue in the bone or soft tissue. ESFTs occur most commonly along the backbone and pelvis and in the legs and arms.