A bone tumor is an abnormal growth of cells within the bone that may be noncancerous (benign) or cancerous (malignant).

The cause of bone tumors is unknown. They often arise in areas of rapid growth. Possible causes include:

• Inherited genetic mutations
• Radiation
• Trauma

But in most cases no specific cause is found.

Osteochondromas are the most common noncancerous (benign) bone tumors, and occur most often in people between the ages of 10 and 20. Some benign bone tumors go away on their own and do not require treatment. These benign tumors are monitored periodically by x-ray.

Cancers that start in the bones are referred to as primary bone tumors. Cancers that start in another part of the body (such as the breast, lungs, or colon) are not considered bone tumors. Multiple myeloma often affects or involves the bone, but is not considered a bone tumor.

Cancerous (malignant) bone tumors include:

• Chondrosarcoma
• Ewing's sarcoma
• Fibrosarcoma
• Osteosarcomas

The most common cancers that spread to the bone are cancer of the:

• Breast
• Kidney
• Lung
• Prostate
• Thyroid

These forms of cancer usually affect older people.

Bone cancer was once very common among people who painted radium on watch faces (to produce glow-in-the-dark dials). The painters would "tip" the brush with their tongue (in order to produce fine work) and absorb minute amounts of radium, which deposited in the bone and caused cancer. The practice of using radium paint was abandoned in the middle of the 20th century.

The incidence of bone cancer is higher in families with familial cancer syndromes. The incidence of bone cancer in children is approximately 5 cases per million children each year.

• Bone fracture, especially fracture from slight injury (trauma)
• Bone pain, may be worse at night
• Occasionally a mass and swelling can be felt at the tumor site

Note: Some benign tumors have no symptoms.

• Alkaline phosphatase
• Bone biopsy
• Bone scan
• MRI
• X-ray of bone

This disease may also affect the results of the following tests:

• Alkaline phosphatase isoenzyme
• Calcium (ionized)
• Extremity x-ray
• Hands x-ray
• Joints x-ray
• PTH
• Serum calcium
• Serum phosphorus

Benign bone tumors may not require treatment, but may be looked at regularly to check if they grow or shrink. Surgical removal of the tumor may be necessary.

Treatment for malignant tumors that have spread to the bone depends on the primary tissue or organ involved. Radiation therapy with chemotherapy or hormone therapy is often used.

Tumors that start in the bone (primary malignant tumors of the bone) are rare and require treatment at centers with experience treating these cancers. After biopsy, a combination of chemotherapy and surgery is usually necessary. Radiation therapy may be needed before or after surgery.

You can often help the stress of illness by joining a support group where members share common experiences and problems. For this condition, see cancer - support group.

The outlook depends on the type of tumor. The outcome is expected to be good for people with noncancerous (benign) tumors, although some types of benign tumors may eventually become cancerous (malignant).

With malignant bone tumors that have not spread, most patients achieve a cure. Because the cure rate depends on the type of cancer, location, size, and other factors, discuss your situation with your doctor.

• Pain
• Reduced function, depending on the extent of the tumor
• Side effects of chemotherapy (depending on the type of chemotherapy)
• Spread of the cancer to other nearby tissues (metastasis)

Call your health care provider if you have symptoms of a bone tumor.

Skubitz KM, D'Adamo D. Sarcoma. Mayo Clin Proc. 2007;82:1409-1432.