Cancer that begins in the bone (known as primary bone cancer) is not the same disease as cancer that starts in another part of the body and spreads (or metastasizes) to the bone, called secondary bone cancer or metastatic cancer. Although tumors may develop in any of the bones of the body, primary bone cancer most often develops in the long bones of the arms and legs. Bone cancer is rare in adults, accounting for fewer than 0.2 percent of all cancers, according to the American Cancer Society. Primary bone tumors, which develop in the bone, are called sarcomas and are malignant (cancerous). Sarcomas can form anywhere in the body, including bone, muscle, fibrous tissue, blood vessels, fat tissue and other tissues.
Bone cancer is more commonly the result of cancer from another site that has metastasized to the bones. Since bone metastasis and primary site bone cancer may have similar signs and symptoms, a biopsy is often needed to determine the cause. New bone metastases are usually diagnosed via imaging tests.
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