What is Fibrous Dysplasia?

What is Fibrous Dysplasia?

Fibrous dysplasia is a rare bone disorder in which abnormal, fiber-like tissue grows in place of healthy bone. The irregular tissue can expand over time, causing the affected bone to weaken, fracture, or develop deformities. 

Symptoms of fibrous dysplasia can be mild to severe. It is typically a benign condition (less than 1% of cases are cancerous). While fibrous dysplasia is chronic and incurable, there are many available treatments that can repair and stabilize the affected bone, and provide relief from bone pain. 

Types of Fibrous Dysplasia


Fibrous dysplasia can affect one bone, multiple bones, or the entire skeleton. There are two types of fibrous dysplasia: 

  • Monostotic fibrous dysplasia – The most common form of fibrous dysplasia in which only one bone is affected
  • Polyostotic fibrous dysplasia – Multiple bones are affected within the same limb or throughout the body. Generally diagnosed at a young age, this form of fibrous dysplasia tends to be the more severe.

Fibrous dysplasia most often affects the long bones in the arms and legs, but can cause problems in any bone in the body. The most commonly affected bones include: 

  • Thighbone (fibrous dysplasia of the femur)
  • Humerus (upper arm bone between the elbow and shoulder)
  • Tibia (shinbone)
  • Cranial bones (fibrous dysplasia of the skull, for example)
  • Ribs
  • Pelvic bone

Signs & Symptoms of Fibrous Dysplasia


Fibrous dysplasia symptoms vary depending on which bones are affected and how many. You could have very few symptoms or none at all. Some cases can be unintentionally discovered during an X-ray for separate issues. 

For people with more severe forms of fibrous dysplasia, the signs and symptoms can include: 

  • Weakness and pain in the affected area
  • Fatigue, especially in children
  • Bone breakage or bone fractures
  • Bone deformity/misshapen bones 
  • Scoliosis (curvature of the spine)

Abnormal bone development can also lead to nerve compression and arthritis in the affected area. Complications from fibrous dysplasia in the skull/cranial area can include vision loss, hearing impairment, and nasal congestion. 

Another form of polyostotic fibrous dysplasia, called McCune-Albright syndrome (MAS), may be associated with abnormalities of the hormone-producing glands in the endocrine system. This may cause symptoms in younger people such as: 

  • Early onset of puberty
  • Skin discoloration (aka “café au lait” spots) 
  • Hyperthyroidism (overactive thyroid)

What Causes Fibrous Dysplasia?


Fibrous dysplasia may be tied to a gene mutation present in cells involved in bone production. The cause of this gene mutation is unknown, but it appears not to be genetically transmitted, which means you can’t inherit it from your parents or pass it on to a child. The gene mutation occurs after conception, resulting in the development of irregular, fibrous bone tissue.

Risk Factors

Risk Factors

Fibrous dysplasia can be diagnosed at any age, affects females and males equally, and is not linked to any specific ethnicity. While anyone can develop fibrous dysplasia, most single-bone cases develop in young adults and adolescents. Patients who develop the condition in more than one bone usually exhibit symptoms before the age of 10.

Get Care

Trust NewYork-Presbyterian for Fibrous Dysplasia Care

Though fibrous dysplasia is a rare condition, the expert physicians at NewYork-Presbyterian are familiar with its symptoms and causes. Our top-notch team of medical professionals can deliver a diagnosis and offer a range of treatments, including medications and surgical and non-surgical options.

NewYork-Presbyterian Columbia Orthopedics offers unparalleled treatment of orthopedic diseases, injuries, and disorders in people of all ages and backgrounds. If you or your child are experiencing symptoms of fibrous dysplasia, don’t hesitate to reach out to us.