A tumor is a lump or mass of tissue that forms when cells divide uncontrollably. For most bone tumors, the cause is unknown. A growing tumor may replace healthy tissue with abnormal tissue. It may weaken the bone, causing it to break (fracture). Aggressive tumors can lead to disability or death, particularly if signs and symptoms are ignored.
Most bone tumors are non-cancerous (benign). Some are cancerous (malignant). Occasionally infection, stress fractures and other non-tumor conditions can closely resemble tumors. Benign tumors are usually not life threatening. Malignant tumors can spread cancer cells throughout the body (metastasize). This happens via the blood or lymphatic system. Cancer that begins in bone (primary bone cancer) is different from cancer that begins somewhere else in the body and spreads to bone (secondary bone cancer). The four most common types of primary bone cancer are:
- Multiple Myeloma, the most common primary bone cancer, is a malignant tumor of bone marrow. It affects approximately 20 people per million people each year. Most cases are seen in patients aged 50 to 70 years old. Any bone can be involved.
- Osteosarcoma is the second most common bone cancer. It occurs in two or three new people per million people each year. Most cases occur in teenagers. Most tumors occur around the knee. Other common locations include the hip and shoulder.
- Ewing's sarcoma most commonly occurs between age 5 and 20. The most common locations are the upper and lower leg, pelvis, upper arm and ribs.
- Chondrosarcoma occurs most commonly in patients 40 to 70 years of age. Most cases occur around the hip and pelvis or shoulder.
There are many types of benign bone tumors. The more common types include non-ossifying fibroma, unicameral (simple) bone cyst, osteochondroma, giant cell tumor, enchondroma and fibrous dysplasia.
If you think you might have a bone tumor, see your doctor as soon as possible for diagnosis and treatment. The doctor will collect detailed information about your general health and the tumor's type, size, location and possible extent of spread.