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Genetic and Rare Diseases Information Center (GARD)

Fibrous dysplasia

Other Names for this Disease
  • Fibrous dysplasia of bone
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Your Question

I would like to learn more about fibrous dysplasia, particularly of the skull. Can you help?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is fibrous dysplasia?

Fibrous dysplasia is a progressive bone disorder that is characterized by the replacement of normal bone with weaker tissues, such as fibrous tissue and woven bone.  It may involve one bone (monostotic) or multiple bones (polyostotic).[1]  Though many individuals with this condition do not have any symptoms, others may have bone pain, abnormally shaped bones, or an increased risk of breaking bones.[2]  This condition can occur alone or as part of a genetic disorder, such as McCune-Albright syndrome.[1][3][4]
Last updated: 8/25/2011

What part of the body does fibrous dysplasia typically affect?

Monostotic fibrous dysplasia is the most common type of fibrous dysplasia. It typically occurs in the skull, ribs, thigh bone, upper arm, or shin bone.[1][3] For the polyostotic form the lesions often occur in the thigh bone, skull, shin bones, upper arm, ribs, lower arm bones, jaw, and spine. The head and/or face is involved in around half of people with a moderate number of bones affected, and in nearly all with many bones affected.
Last updated: 2/27/2009

What are the symptoms of fibrous dysplasia?

Fibrous dysplasia may cause no symptoms, mild symptoms, or severe symptoms. The monostotic form is typically milder and these lesions may stop growing.[1] The lesions due to the polyostotic form can continue to grow.[1] Symptoms of fibrous dysplasia may include bony deformity, fracture, hearing loss, vision loss, and cranial nerve palsies.[3] The polyostotic form tends to involve the shoulder and pelvic girdles which can cause severe, sometimes crippling, bone deformities. Lesions involving the face can distort the facial appearance.[4]

Cases of fibrous dysplasia affecting the skull, more specifically the temporal bone of the skull, have been reported in the literature.[1] The process usually begins as a painless slow swelling. However as the lesion grows it can put pressure on ear structures (i.e., the external auditory canal, middle ear, ossicles, or Eustachian tube) and cause conductive hearing loss.[1] Nonthrobbing headache is also commonly reported.[4] More rarely cases of facial nerve paralysis, sensoryneural hearing loss, ringing of the ears, vision loss, and vertigo have been reported.[1][3][4]
Last updated: 2/27/2009

Can fibrous dysplasia become cancerous?

Rarely (less than 1% of the time) the lesions become cancerous and transform into a sarcoma or sarcoma like tumor.[1]
Last updated: 2/27/2009

What causes fibrous dysplasia?

The cause of fibrous dysplasia has been linked to a gene mutation that occurs in the body, prior to birth.[3][4] The mutation involves a gene that affects the cells that produce bone. People with fibrous dysplasia carry this mutation in some, but not all cells of their body. It is not well understood why the mutation occurs, but it is not inherited from a parent, nor can it be passed on to future offspring.[5]
Last updated: 2/27/2009

How might fibrous dysplasia be treated?

Unfortunately, there is no cure for fibrous dysplasia.[6]  Treatment of fibrous dysplasia depends on the symptoms that develop.  Surgery can often treat broken bones or significant bone malformations, though problems can recur and multiple procedures may be needed.[1][4]  A group of medications known as bisphosphonates has been shown to relieve bone pain in both adults and children.[7]  In adults only, these medications have also been shown to strengthen normal bone by preventing it from being replaced by weaker tissues or by increasing the thickness of the bone (density).  These medications have not been shown to prevent fractures or bone malformations.[8]  Calcium and vitamin D supplements may also be considered to help promote bone health.[2]  Radiotherapy is not recommended because it is associated with an increased risk of fibrous dysplasia becoming cancerous.[1][3][4]  Careful, long-term follow-up to monitor fibrous dysplasia is advised, particularly during pregnancy because the lesions may progress more rapidly during this period.[1][4]
Last updated: 8/25/2011

  • Merchant SN, Nadol JB Jr. Otologic manifestations of systemic disease. In: Cummings CW et al., eds. Otolaryngology: Head & Neck Surgery, 4th ed. Philadelphia, PA: Mosby, Inc; 2005;
  • Chapurlat RD, Meunier PJ. Fibrous dysplasia of the bone. Bailliere's Best Practices & Research. Clinical Rheumatology. 2000; 14:385-398. Accessed 8/23/2011.
  • Rosenberg AE. Bones, joints, and soft tissue tumors. In: Kumar V et al., eds. Pathologic Basis of Disease, 7th ed. Philadelphia PA: Saunders; 2005;
  • Feske SK, Cochrane TI. Degenerative and compressive structural disorders. In: Goetz CG. Textbook of Clinical Neurology, 3rd ed. Philadelphia PA: Sunders; 2007;
  • Fibrous dysplasia. 2007; Accessed 2/27/2008.
  • Kaneshiro NK, Zieve D. Fibrous dysplasia. MedlinePlus. 08/02/2011; Accessed 8/23/2011.
  • Plotkin H, Rauch F, Zeitlin L, Munns C, Travers R, Glorieux FH. Effect of pamidronate treatment in children with polyostotic fibrous dysplasia of bone. Journal of Clinical Endocrinology and Metabolism. 2003; 88:4569-4575. Accessed 8/23/2011.
  • Silverman SL. Bisphosphonate use in conditions other than osteoporosis. Annals of the New York Academy of Sciences. 2011; 1218:33-37. Accessed 8/23/2011.
Other Names for this Disease
  • Fibrous dysplasia of bone
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.