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- Overview
- Causes
- Symptoms
- Diagnosis
- Treatment
- Helpful Tips
- Additional Resources
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Overview
Fibrous dysplasia (FD) is a rare disease where normal bone is replaced with scar-like fibrous tissue. This condition can occur in any bone in the body and can sometimes affect more than one bone. The most common sites for fibrous dysplasia are the bones in the skull and face, the long bones in the arms and legs, and the ribs.
Fibrous dysplasia can occur alone or as part of McCune-Albright Syndrome (MAS). In MAS, the endocrine system (hormone-producing system) and skin are also affected. Fibrous Dysplasia/McCune Albright Syndrome (FD/MAS) can range from mild, with few signs and symptoms, to severe, involving almost all the skeleton.
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Causes
The cause of FD/MAS is a change (mutation) in a gene. This change occurs as the baby is developing in the womb. Normally, bone constantly remodels itself, breaking down old bone and forming new bone. The genetic change in FD/MAS causes a glitch in the bone formation process. As a result, the new bone that forms is a fibrous, scar-like tissue. People with FD/MAS carry the mutation in some, but not all, of the cells of their body. Although scientists do not understand the reason for this genetic change, they know that it is not inherited, or passed on from parents to children.
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Symptoms
Signs and symptoms of fibrous dysplasia/McCune-Albright Syndrome depend on which body systems are affected.
| Affected Area | Signs & Symptoms |
|---|---|
| Skeleton |
|
| Endocrine System |
|
| Head and Face |
|
| Teeth |
|
| Skin |
|
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Diagnosis
A diagnosis of FD/MAS is confirmed by the doctor’s findings during a physical exam and the results of tests and imaging studies. The table below shows what may be done to reach an FD/MAS diagnosis.
| Diagnostic Test | Why it’s done | How it’s done |
|---|---|---|
| Bone Scan | Shows where the FD is present. | In this test, a safe radioactive material is injected into a vein, and a special camera is used to detect uptake of the material by the bones. The radioactive material accumulates more in the areas of FD, which is shown in the pictures taken by the camera. |
| Bone Biopsy | Enables doctors to examine a small piece of bone under a microscope. | A needle or other instrument is used to obtain a bone sample. |
| Bloodwork | Measures the levels of hormones and other substances in the blood. | A needle is used to take blood from a vein. |
| Ultrasound | Allows checking a person’s ovaries, testicl*s, or thyroid. | This procedure uses high-energy sound waves to look at tissues and organs inside the body. The sound waves make echoes that form pictures of the tissues and organs on a computer screen. |
| Genetic Tests | Identifies gene changes (mutations). | Blood is drawn from a vein, or tissue from one of the affected bones is collected through a bone biopsy. Then tests are done to see if the mutation is present. Blood tests may not always be able to identify the mutation. |
| Computed Tomography (CT) | Examines facial structures, including the upper and lower jaws. | This procedure uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body. The pictures are taken from different angles and are used to create 3-dimensional (3-D) views of tissues and organs. |
| Bone or dental X-rays | Captures images of the bones and teeth. | This procedure uses a type of high-energy radiation called x-rays to take pictures of areas inside the body. X-rays pass through the body onto film or a computer, where the pictures are made. |
| Hearing and Vision Tests | Determines the extent to which hearing and vision have been affected by FD/MAS. | Depends on the test. There are several types of hearing tests. Similarly, different tests are done during an eye exam. The health care team will tell you which tests are right for you. |
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Treatment
There is no cure for FD/MAS. Treatments – listed in the table below – are aimed at managing problems associated with this disorder and include repairing or stabilizing bones, relieving pain, and correcting abnormal hormone levels.
As part of treatment, bisphosphonates may be prescribed to help with bone pain. Talk to your dentist if you or your child are taking bisphosphonates, because they can increase the risk that the jaw won’t heal correctly after a dental procedure.
| Treatment | Purpose |
|---|---|
| Medications | To correct hormone imbalances and treat bone pain. |
| Surgery | To reshape or remove bone affected by FD, and to correct abnormalities in the limbs or spine. |
| Physical Therapy | To maintain strength and joint mobility. |
| Orthodontic Treatment | Orthodontic treatment (such as braces) may be used to correct misaligned teeth. |
| Other Dental Treatments | May include more frequent dental cleanings and visits, using fluoride for cavity protection, or dental implants. |
Because FD/MAS can affect different body systems, you may need to work with a team of specialists.
| Specialist | Area of Focus |
|---|---|
| Orthopedic Surgeon | Bones and joints. |
| Endocrinologist | Hormones and metabolism. |
| Oral, Maxillofacial, or Craniofacial Surgeon | Surgeries of the mouth, jaws, head, neck, and face. |
| Plastic and Reconstructive Surgeon | Surgeries to repair physical deformities. |
| Otolaryngologist | Ear, nose, and throat. |
| Neurosurgeon | Surgeries of the brain, spinal cord, and nerves. |
| Dentist | Teeth and mouth. |
| Orthodontist | Alignment of the teeth and jaw. |
| Physiatrist | Strength and function of muscles and joints. |
| Speech and Language Pathologist | Speech, language, and swallowing. |
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Helpful Tips
For FD/MAS that affects the head and skull, you should:
- Find a craniofacial team experienced with treating FD/MAS.
- Talk to the dentist before having any dental procedure if you or your child are prescribed bisphosphonates.
- Make sure to follow up with your medical team on a regular basis.
- Have vision and hearing regularly checked.
- Connect with patient advocacy groups about coping with FD/MAS.
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Additional Resources
- Fibrous Dysplasia
Information from NIH’s Genetic and Rare Diseases Information Center on fibrous dysplasia that includes symptoms, causes, treatment, and links to organizations. - Fibrous Dysplasia Overview
Frequently asked questions about fibrous dysplasia from the NIH Osteoporosis and Related Bone Diseases National Resource Center. - Fibrous Dysplasia
Information from the National Library of Medicine's MedlinePlus on fibrous dysplasia. - FD/MAS Alliance
The FD/MAS Alliance (formerly Fibrous Dysplasia Foundation) is a community-driven non-profit that fosters the development of evidence-based treatments for this disorder.
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Last Reviewed
December 2021
