Bone tumors develop when cells in the bone divide without control, forming a mass of tissue. Most bone tumors are benign, which means they are not cancer and cannot spread. However, they may still weaken bone and lead to fractures or cause other problems. Bone cancer destroys normal bone tissue and may spread to other parts of the body (called metastasis).
Benign Bone Tumors
Benign tumors are more common than malignant tumors of the bones. These are a few common types of benign bone tumors:
- Osteochondroma is the most common benign bone tumor. It is more common in people under age 20.
- Giant cell tumor is a benign tumor, typically affecting the leg (malignant types of this tumor are uncommon).
- Osteoid osteoma is a bone tumor, often occurring in long bones, that occurs commonly in the early 20s.
- Osteoblastoma is a single tumor that occurs in the spine and long bones, mostly in young adults.
- Enchondroma usually appears in bones of the hand and feet. It often has no symptoms. It is the most common type of hand tumor.
When people have cancer in bones, often it is cancer that has spread there from elsewhere in the body. This is metastatic cancer. Even though it spreads to bone, it is not considered bone cancer because the tumor cells are from the primary cancer. For example, a person with lung cancer that has spread to the bone is considered to have lung cancer with metastasis to the bone -- not lung cancer and bone cancer.
Cancers that commonly spread to bone include:
- Breast cancer
- Prostate cancer
- Lung cancer
Primary Bone Sarcoma
Primary bone sarcoma is a tumor that forms first in bone. It is less common than metastatic cancer. The cause of bone sarcoma is not certain, but heredity may play a role. High-dose radiation therapy or cancer drugs may increase the risk of this type of cancer. These are some of the most common types of bone cancer:
- Osteosarcoma begins in bone cells and is most common around the knee and upper arm. Most of the time, it is found in teens and young adults. There is an adult form of this tumor that is usually seen in persons with pre-existing Paget’s disease of bone.
- Ewing's sarcoma also is seen in younger people between the ages of 5 and 20. The ribs, pelvis, leg, and upper arm are the most common sites. It usually shows up in bone, but it can also start in soft tissue around bones.
- Chondrosarcoma occurs most often in people between 40 and 70. The hip, pelvis, leg, arm, and shoulder are common sites of this cancer, which begins in cartilage cells.
Although almost always found in bone, multiple myeloma is not a primary bone cancer. It is a bone marrow cancer. Bone marrow is the soft tissue inside bones.