Osteoid osteoma
Disease Information
In-Depth
What is osteoid osteoma?
An osteoid osteoma is a benign (non-cancerous), small tumor that occurs most often in the long bones of a person’s lower extremities. The thighbone is the most common location it grows, although it can emerge in the bones of the hand and it sometimes occurs in the lower part of the spine.
The tumor may cause pain, but it doesn’t spread. In young children, it may deform the host bone, or stimulate the bone to grow larger or longer.
What causes osteoid osteoma?
An osteoid osteoma occurs when certain cells divide uncontrollably, forming a small mass of bone and other tissue. This growing tumor replaces healthy bone tissue with abnormal, hard bone tissue. No one knows exactly why this occurs.
Is osteoid osteoma common?
It usually emerges sometime during the teenage years or early adulthood. The condition seems to occur more often in boys than girls.
What are the symptoms of osteoid osteoma?
While symptoms may vary child-to-child, the most common include:
- dull or sharp pain that worsens at night
- pain that is usually relieved by aspirin or other anti-inflammatory drugs
- limping
- painful scoliosis and muscle spasticity (when tumor is located in the spine)
- growth disturbance (when tumor is involved with a bone's growth plate)
- muscle wasting away
- bowing deformity
- nerve symptoms (like sciatica) when located in the spine


