The cause of bone tumors is unknown. They often arise in areas of rapid growth. Possible causes include inherited mutations, trauma and radiation, but in most cases no specific cause is found.

Bone tumors may be benign or malignant. Osteochondromas are the most common 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.

Malignant bone tumors occur as a primary bone tumor or as metastasis (cancer spread from another area of the body). Primary bone tumors are rare (less than 1% of all malignant tumors) and are most common in young men.

Malignant bone tumors include osteosarcomas, Ewing's sarcoma, fibrosarcoma, and chondrosarcoma. The most common cancers that spread to the bone are cancer of the breast, lung, prostate, kidney, and thyroid. These forms of cancer usually affect older people.

Bone cancer was once prevalent among individuals who painted radium on watch faces (to produce glow-in-the-dark dials), a practice that was abandoned in the middle of the 20th century. The painter 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 incidence of bone cancer is also increased in families with familial cancer syndromes. The incidence of bone cancer in children is approximately 5 cases per million children each year.

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

• X-ray of bone
• Bone biopsy
• Bone scan showing size and location of tumor
• Alkaline phosphatase may be elevated

• PTH
• Serum phosphorus
• Joints X-ray
• Hands X-ray
• Extremity X-ray
• Calcium (ionized)
• Serum calcium
• ALP (alkaline phosphatase) isoenzyme

Benign bone tumors may not require treatment but may be assessed periodically to check for progression or regression. Surgical removal may be necessary.

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

Primary malignant tumors of bone (tumors that start in 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.

• Pain
• Function may be reduced depending on the extent of the tumor
• Spread of the cancer to other nearby tissues (metastasis)
• Side effects of chemotherapy (if necessary) depend on the specific chemotherapy given