Fibrous Dysplasia

What is Fibrous Dysplasia?

Fibrous dysplasia is a condition that falls under the category of a bone disorder. It is a rare condition that is benign (noncancerous) and involves the bones in the body growing abnormally. These bones are made from fibrous tissue rather than from actual bone. Fibrous tissue is similar to scar tissue and is not as strong or durable as bone.

When a person has fibrous dysplasia, the areas of fibrous tissue in place of actual bone tend to grow as time goes on. Those bones can eventually become so weakened that they fracture or become deformed. This condition varies in severity based on whether it affects one bone or several bones and which bones are affected.

Any bone in the body can suffer from fibrous dysplasia. This condition occurs due to a gene defect in one of the genes that are responsible for the formation of bone tissue. As such, there is no known cure for fibrous dysplasia.

What are the Symptoms of Fibrous Dysplasia?

Fibrous dysplasia is present even before birth. However, this does not mean that symptoms will arise until later in childhood, adolescence or even adulthood.

Symptoms include

When symptoms do occur, they can include bone pain and aching, which is especially noticeable if the affected bone is weight-bearing (such as those in the leg or pelvis). Fractures are also symptoms of fibrous dysplasia and can occur with no prior warning but are often preceded by aching and pain. And, of course, deformities in the bones making them appear misshapen and structurally unsound are also common signs of fibrous dysplasia.

Fibrous Dysplasia Causes

Fibrous Dysplasia is an uncommon disease with a significant genetic component. It occurs when certain cells that produce bone have mutations. These mutated cells produce a scar-like, fibrous substance instead of bone. Typically, this is limited to a single site on a single bone, although in rare cases, it may occur on multiple bones. Fibrous dysplasia is a benign (non-cancerous) disorder, although it has the ability to weaken bones. As it is a chronic condition, bones may weaken over time even if lesions stop growing.

The genetic mutation that causes fibrous dysplasia occurs in the early stages of fetal development. It is not transmitted from parent to child, but rather a mistake in a gene that occurs when the fetus is developing. The specific cause of this genetic mutation is unknown, and it occurs equally across the population.

How is Fibrous Dysplasia Treated?

Treating fibrous dysplasia depends on the severity of the condition.

Treatment includes

In mild cases or in cases in which major bone deformities or fractures have yet to occur, management may involve prescription osteoporosis drugs to increase bone strength and maintain bone density. If bone lesions (areas of fibrous tissue) are causing significant pain, physical deformities, or are pinching nerves, surgical procedures can be performed to relieve pressure on the nerves, rebuild or correct bone shape or to fix fractures. Some of these procedures include metal implants or bone grafts to help add structure to the bones.

Fibrous Dysplasia Prevention

Because fibrous dysplasia is genetic and not transmittable from parent to child, there is no way to prevent it.

Typically, lesions occur during and are limited to puberty, although they can occur during pregnancy as well. In cases where lesions develop on multiple bones, fibrous dysplasia usually presents itself before the age of 10. Often, however, this condition is not discovered until much later, as symptoms can be difficult to discern in all but the most severe cases.

While the condition itself cannot be prevented, treatment aims to protect against complications that occur as a result of the disease. Fibrous dysplasia causes bones to weaken, and so fractures are more likely for people with this condition. Bone fractures are treated as normal, and patients are screened for endocrine disorders if necessary. As fibrous dysplasia is progressive, its effects cannot be stopped, but lessening complications such as bone fractures can make the impact of it less severe.

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Last Reviewed:
September 21, 2016
Last Updated:
December 22, 2017