Bone tumors may be benign (noncancerous) or malignant (cancerous). Benign bone tumors are more common than malignant ones. Both types may grow and compress healthy bone tissue and absorb or replace it with abnormal tissue. However, benign tumors do not spread and are rarely life-threatening.

Cancer that arises in the bone (primary bone cancer) is not the same disease as cancer that spreads to the bone from another part of the body (secondary bone cancer). Primary bone cancer is rare, with approximately 2,500 new cases diagnosed each year in the United States. More commonly, bones are the site of tumors that result from the spread (metastasis) of cancer from another organ, such as the breasts, lungs, and prostate.

The most common type of bone cancer is osteosarcoma, which develops in new tissue in growing bones. Another type of cancer, chondrosarcoma, arises in cartilage. Evidence suggests that Ewing’s sarcoma, another form of bone cancer, begins in immature nerve tissue in bone marrow. Osteosarcoma and Ewing’s sarcoma tend to occur more frequently in children and adolescents, while chondrosarcoma occurs more often in adults