Bone cancer is a disease caused by a tumor that destroys bone tissue. According to the National Cancer Institute, benign or noncancerous bone tumors are more common than malignant tumors; however, both types of tumors can compress normal bone tissue. While some forms of bone cancer begin in the bone itself, other tumors develop in distant locations in the body and spread to the bone.
Benign Bone Cancers
Benign bone cancers are those caused by noncancerous tumors that do not spread throughout the body and are usually not life-threatening, according to the American Cancer Society. Common benign bone tumors include osteoblastoma, osteochondroma, osteoid osteoma, enchondroma and chondromyxoid fibroma. Other benign bone cancers include non-ossifying fibromaunicameral (simple) bone cyst and fibrous dysplasia, the American Academy of Orthopaedic Surgeons notes.
Primary, Malignant Bone Cancers
According to the American Academy of Orthopaedic Surgeons, multiple myeloma is the most common primary bone cancer, affecting roughly 20 million people each year. However, according to the American Cancer Society, physicians usually do not consider it a bone cancer because it develops from plasma cells in bone marrow and not from tumors in the bone. Rarely, it may be discovered to start as a single tumor in one bone.
Osteosarcoma, or osteogenic sarcoma, is another common primary malignant bone cancers. Often developing in the bone cells of the arms, legs or pelvis, osteosarcoma commonly occurs in people between age 10 and 30. Chondrosarcoma is the second most common primary malignant bone cancer. It can start in any site where there is cartilage, commonly in the pelvis, legs or arms, according to the American Cancer Society.
Ewing Sarcoma is the second most common primary bone cancer in children, adolescents and young adults and the third most common overall. These tumors usually start in the bones of the pelvis, ribs, shoulder blades, legs or arms, although they sometimes may develop in other tissues or organs.
Chordoma is a primary malignant bone tumor that typically develops at the base of the skull or in the spinal bones. It usually is slow-growing and spreads throughout the body only rarely, although it may recur in the same spot if not removed in its entirety.
Primary malignant cancers that can start in bones but more often start in connective tissues such as ligaments, tendons, muscle and fat include fibrosarcoma and malignant fibrous histiocytoma.
Giant cell tumors are a type of primary bone tumor that typically develop in the leg. They can be benign or malignant, although the benign form is most common. While the malignant form may spread to other parts of the body, the noncancerous form is more likely to recur in the same spot, even after surgery, the American Cancer Society reports.
Secondary and Metastatic Bone Cancers
Metastatic bone cancers are those that start in the bone and spread to other locations in the body. For example, if cancer that starts in the pelvic bone spreads to the lungs, the cancer cells found in the lungs will be bone cancer cells, according to eMedTV.
Secondary bone cancers are those that start somewhere else in the body--for example, the breast or pancreas--and spread to the bone. According to eMedTV, secondary bone cancers are significantly more common than primary bone cancers.
