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 noncancerous (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:

There are many types of benign bone tumors. The more common types include

• Non-ossifying fibromaunicameral (simple) bone cyst
• Osteochondroma
• Giant cell tumor
• Enchondroma
• Fibrous dysplasia

Most patients with a bone tumor will experience pain in the area of the tumor. The pain is generally described as dull and achy. The pain may or may not get worse with activity. The pain often awakens the patient at night.

Although tumors are not caused by trauma, occasionally injury can cause a tumor to start hurting. Injury can cause a bone that is already weakened by a tumor to break. This often leads to severe pain. Some tumors can cause fevers and night sweats. Many patients will not have any symptoms, but will instead note a painless mass.

Occasionally benign tumors may be discovered incidentally when X-rays are taken for other reasons, such as a sprained ankle or rotator cuff problem.

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 general health and the tumor's type, size, location, and possible extent of spread.

In many cases, benign tumors just need to be watched. Some can be treated effectively with medication. Some benign tumors will disappear over time. This is particularly true for some benign tumors that occur in children.

Certain benign tumors can spread or become cancerous (metastasize). Sometimes the doctor may recommend removing the tumor (excision) or some other treatment techniques to reduce the risk of fracture and disability. Some tumors may come back, even repeatedly, after appropriate treatment.

If you are diagnosed with a malignant bone tumor, you might want to get a second opinion to confirm it. If you have bone cancer, the treatment team may include several specialists. These may include an orthopaedic oncologist, a medical oncologist, a radiation oncologist, a radiologist, and a pathologist. Treatment goals include curing the cancer and preserving the function of the body.

Doctors often combine several methods to treat malignant bone tumors. Treatment depends upon various factors, including the stage of the cancer (whether the cancer has spread).

• Localized stage
  Cancer cells are contained to the tumor and surrounding area.
• Metastatic stage
  Cancers have spread elsewhere in the body. Tumors at this stage are more serious and harder to cure.

Generally, the tumor is removed using surgery. Often, radiation therapy is used in combination with surgery.

When treatment for a bone tumor is finished, the doctor may take more X-rays and other imaging studies. These can confirm that the tumor is actually gone. Regular doctor visits and tests every few months may be needed. When the tumor disappears, it is important to monitor your body for signs that is may have returned (relapse).

Genetic research is leading to a better understanding of the types of bone tumors and their behaviors. Researchers are studying the design of metallic implants. This allows better function and durability after limb salvage surgery.

Advancements in the development of prosthetic limbs include computer technology. This is leading to better function and quality of life after amputation.

Research into new medications and new combinations of older medications will lead to continual improvements in survival from bone cancers. Your doctor may discuss clinical research trials with you. Clinical trials may involve the use of new therapies and may offer a better outcome.