What is fibrous dysplasia?
Fibrous dysplasia is a chronic disorder in which bone expands due to abnormal development of fibrous tissue, often resulting in one, or more, of the following:
Uneven growth of bones
Any bone can be affected. More than one bone can be affected at any one time, and, when multiple bones are affected, it is not unusual for them to all be on one side of the body. However, fibrous dysplasia does not spread from one bone to another. The most commonly affected bones include the following:
Tibia (shin bone)
Humerus (the bone of the upper arm)
Vertebrae in the spine (less often)
Some people develop hormonal problems and a condition called McCune-Albright syndrome. McCune-Albright syndrome, another form of fibrous dysplasia, includes different symptoms, such as early onset of puberty and skin spots, called café-au-lait spots.
Fibrous dysplasia usually occurs in children ages 3 to 15, but it sometimes is not diagnosed until adulthood. It is found equally between males and females.
What causes fibrous dysplasia?
The exact cause of fibrous dysplasia is not known, but it is believed to be due to a chemical irregularity in a specific bone protein. This bone protein abnormality may be due to a gene mutation present at birth, although it is not known to be an inherited disorder.
What are the symptoms of fibrous dysplasia?
The following are the most common symptoms for fibrous dysplasia. However, each individual may experience symptoms differently. Symptoms may include:
A waddling walk
Bone pain (as a consequence of the expanding fibrous tissue in the bone)
Scoliosis. A lateral, or sideways, curvature and rotation of the back bones (vertebrae), giving the appearance that the person is leaning to one side.
The symptoms of fibrous dysplasia may resemble other bone disorders or medical problems. Always consult your doctor for a diagnosis.
How is fibrous dysplasia diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures for fibrous dysplasia may include the following:
X-ray. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
Biopsy. A procedure in which tissue samples are removed (with a needle or during surgery) from the body for examination under a microscope; to determine if cancer or other abnormal cells are present; to remove tissue from the affected bone.
Computed tomography scan (also called a CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
Treatment for fibrous dysplasia
Specific treatment for fibrous dysplasia will be determined by your doctor based on:
Your age, overall health, and medical history
Extent of the disease
Your tolerance for specific medications, procedures, or therapies
Expectations for the course of the disease
Your opinion or preference
Treatment may include:
Surgery, including the following:
Removal of affected bone, followed by bone grafting. This is a surgical procedure in which healthy bone is transplanted from another part of the patient's body into the affected area.
Removal of bone wedge
Placement of a rod down the shaft of the bone