Fibrous dysplasia is an uncommon bone disorder in which scar-like (fibrous) tissue develops in place of normal bone. This can weaken the affected bone and cause it to deform or fracture.
In most cases, fibrous dysplasia affects only a single bone — most commonly the skull or a long bone in the arms or legs. This variety usually occurs in adolescents and young adults. People who have more than one affected bone typically develop symptoms before the age of 10.
Fibrous dysplasia is a genetic disorder and there's no cure. Treatment, which may include surgery, focuses on relieving signs and symptoms.
Fibrous dysplasia may cause few or no signs and symptoms, particularly if the condition is mild. More severe fibrous dysplasia may cause:
- Bone pain
- Bone deformities
- Nerve entrapment
Rarely, fibrous dysplasia may be associated with abnormalities in the hormone-producing glands of your endocrine system. These abnormalities may include:
- Very early puberty
- Thyroid gland problems
- Light brown spots on the skin
When to see a doctor
See your doctor if you or your child develops bone pain that:
- Increases with weight-bearing activity
- Interrupts sleep
- Doesn't go away with rest
- Causes a limp
Fibrous dysplasia is linked to a gene mutation that affects the cells that produce bone. The mutation occurs after conception, in the early stages of fetal development. That means the mutation isn't inherited from your parents, and you can't pass it on to your children.
Severe fibrous dysplasia can cause:
- Bone deformity or fracture. The weakened area of an affected bone can cause the bone to bend. These weakened bones also are more likely to fracture.
- Vision and hearing loss. The nerves to your eyes and ears may be surrounded by affected bone. Severe deformity of facial bones can lead to loss of vision and hearing, but it's a rare complication.
- Arthritis. If leg and pelvic bones are deformed, arthritis may form in the joints of those bones.
- Cancer. Rarely, an affected area of bone can become cancerous. This rare complication usually only affects people who have had prior radiation therapy.
Most people with fibrous dysplasia don't have any symptoms and are diagnosed when an X-ray taken for another reason reveals signs of fibrous dysplasia.
However, in some cases you or your child may experience pain and other symptoms that lead you to schedule an appointment with your family doctor or your child's pediatrician. In some cases, you may be referred to a doctor who specializes in treating bone and muscle injuries or disorders (orthopedic surgeon).
What you can do
Before your appointment, you might want to compose a list of answers to the following questions:
- When did symptoms begin?
- Does any specific activity make the symptoms worse?
- What medications or supplements do you or your child take regularly?
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
- Have symptoms been continuous or occasional?
- How severe are the symptoms?
- Does pain wake you or your child up at night?
- Is the pain or deformity getting better, staying the same or getting worse?
If you have a mild form of fibrous dysplasia, you may not know it until it's discovered incidentally on an X-ray for another condition. If you have signs and symptoms, your doctor will perform a physical examination and order X-rays of the affected bones.
In some cases, your doctor may order more tests to confirm the diagnosis or to determine the extent of the disorder. They include:
- Imaging tests. Computerized tomography or magnetic resonance imaging scans may be used to determine how extensively your bones are affected.
- Bone scan. This test uses radioactive tracers, which are injected into your bloodstream. The damaged parts of your bones take up more of the tracers, which show up more brightly on the scan.
- Biopsy. This test uses a hollow needle to remove a small piece of the affected bone for laboratory analysis.
If you have mild fibrous dysplasia that's discovered incidentally and you have no signs or symptoms, your risk of developing deformity or fracturing your bone is low. Your doctor can monitor your condition with periodic X-rays.
Osteoporosis medications, particularly pamidronate (Aredia), may help strengthen bones affected by fibrous dysplasia. This can relieve pain and help reduce the risk of fractures.
Your doctor may recommend surgery in order to:
- Correct a deformity
- Correct a difference in limb lengths
- Fix a fracture
- Remove an affected area of bone (lesion) that's causing you difficulty
- Relieve pressure on a nerve, particularly if the lesion is in your skull or face
Surgery may involve removing the bone lesion and replacing it with bone grafted from another part of your body or from bone tissue donated from a deceased donor. Your surgeon may insert metal plates, rods or screws to stabilize the bone and the graft. Risks include infection, blood clots and bleeding. In addition, a bone graft may not last.
Living with a condition such as fibrous dysplasia or having a child with the condition can be stressful. It may be helpful for you to:
- Learn all you can about the condition. Knowing what you might expect in terms of signs and symptoms and what you can do about them may help ease your mind.
- Join a support group. Talking to people with similar concerns — either online or face to face — can help you find solutions to challenges and help you feel that you're not alone. Talk to your doctor to find groups in your area.