Bone tumours occur when abnormal cells in the bones grow in an uncontrolled way. There are 2 main types of bone tumours in children:
- Osteosarcoma forms from cells called osteoblasts. It usually develops at the ends of the long bones, such as the arms or legs.
- Ewing sarcoma (also called Ewing family of tumours) forms from a type of stem cell in the bone marrow. It can form in the bones of the arms, legs, hands, feet, spine, skull, ribs, shoulder blades or hips. Ewing sarcomas can also form in soft tissues near bones. These are called extraosseous or extraskeletal Ewing tumours, and are not discussed in this summary.
Osteosarcoma often develops in bones that are growing quickly, so it can be associated with the teenage growth spurt. Ewing tumours are also more common in teenagers.