Fibrous dysplasia

Fibrous dysplasia, also called inflammatory fibrous hyperplasia, is a bone disorder that destroys normal bone structure and replaces it with scar-like (fibrous) tissue. This can lead to uneven growth, brittleness and deformity of the affected bones. The exact cause of fibrous dysplasia isn't clear.

Although it can occur in any bone in the body, fibrous dysplasia most often affects:

• Thighbone (femur)
• Shinbone (tibia)
• Ribs
• Skull
• Facial bones
• Upper arm bone (humerus)
• Pelvic bones

Fibrous dysplasia isn't cancerous. Mild cases of fibrous dysplasia usually cause no signs or symptoms. In severe cases, signs and symptoms usually appear before age 15 and may include:

• Bone pain
• Difficulty walking
• Bone deformities
• Fractures

A doctor may confirm a diagnosis of fibrous dysplasia by X-rays of affected bones, which have the appearance of ground glass. Some people with fibrous dysplasia also develop hormone problems and pigmented spots on their skin. Doctors refer to this as McCune-Albright syndrome.

There's no cure for fibrous dysplasia. Treatment is directed at relieving signs and symptoms and may include bone grafting.