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​Fibrous Dysplasia

What is Fibrous Dysplasia?

Fibrous dysplasia is a rare bone disorder in which scar tissue develops in place of normal bone tissue, thereby weakening the bone.

The most common bones affected by this disease are skull and facial bones, thighbone, shinbone, pelvic bones, ribs, and upper arm bone.

In most people, only one bone is affected (monostotic fibrous dysplasia). Approximately 20 to 30 percent of cases are polyostotic, which means fibrous dysplasia affects multiple bones.

Fibrous dysplasia is established early in life, and though it does not spread beyond the original scope of affected bones, it is irreversible.

The polyostotic form usually becomes apparent before age 10, whereas detection of the monostotic form depends upon which bone is affected.

Symptoms of fibrous dysplasia in the skull or facial bones may include head, skull, or facial deformities, along with pain and swelling.

At UPMC, the preferred surgical treatment for fibrous dysplasia of the skull base is the Endoscopic Endonasal Approach (EEA). Although fibrous dysplasia is irreversible, the Endoscopic Endonasal Approach allows surgeons to remove the scar tissue. This innovative, minimally invasive technique uses the nose and nasal cavities as natural corridors to access hard-to-reach or previously inoperable fibrous dysplasias.

Benefits of EEA include:

  • No incisions to heal
  • No disfigurement
  • Faster recovery time

Diagnosing Fibrous Dysplasia

To help diagnose fibrous dysplasia your doctor will:

  • Perform a physical exam.
  • Ask you about your symptoms.
  • Order imaging and other diagnostic tests.

Fibrous dysplasia symptoms and associated conditions

Symptoms of fibrous dysplasia may include:

  • Head or facial deformities
  • Bone pain
  • Swelling

Additionally, light brown birth marks (referred to as café-au-lait spots) may accompany fibrous dysplasia, along with endocrine dysfunctions such as premature puberty, hyperthyroidism, and excessive production of growth hormone. These are signals of a condition called McCune-Albright syndrome, of which polyostotic fibrous dysplasia is one manifestation.

Tests for diagnosing fibrous dysplasia

Images provided by x-rays, MRI, and CT scans can reveal the presence of abnormal tissue in bones and the extent to which bones are affected. Your doctor may also order a bone scan.

In cases of polyostotic fibrous dysplasia, blood tests to assess endocrine function also may be required.

Biopsy is used in cases where there is suspicion of cancer. In severe cases of fibrous dysplasia, the bone lesions can become cancerous (malignant). However, this is a rare occurrence.

Fibrous Dysplasia Treatment

Surgery may be necessary for more problematic cases of fibrous dysplasia involving chronic pain, fractures, or deformity.

Surgical treatment for fibrous dysplasia involves removal of the affected bone, followed by a bone graft from another part of the body. Surgeons may also insert stabilizing agents such as metal plates, rods, and screws.

Minimally invasive surgery for fibrous dysplasia of the skull base

Fibrous dysplasia of the skull base may be approached directly using the Endoscopic Endonasal Approach (EEA). Although fibrous dysplasia is irreversible, the Endoscopic Endonasal Approach allows surgeons to remove the scar tissue.

This state-of-the-art, minimally invasive fibrous dysplasia treatment allows surgeons to access fibrous dysplasias through the natural corridor of the nose, without making an open incision. Surgeons then remove the scar tissue through the nose and nasal cavities.

To preserve sight, surgeons will perform optic nerve decompression in cases where the fibrous dysplasia has caused cranial nerve defects by deforming the optic canal.

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