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 the skull and facial bones, thighbone, shinbone, pelvic bones, ribs, and upper arm bone. In most patients, only one bone is affected. Approximately 20 to 30 percent of cases are polyostotic, which means the fibrous dysplasia involves 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 (only one bone is affected) depends upon which bone is affected.
Symptoms of fibrous dysplasia in the skull or facial bones may include head or facial deformities, along with pain and swelling.
The preferred treatment at UPMC for treating fibrous dysplasia in the skull is the Endoscopic Endonasal Approach (EEA). Although fibrous dysplasia is irreversible, the Endoscopic Endonasal Approach allows surgeons to remove scar tissue. This innovative technique involves using the nose and nasal cavities to reach fibrous dysplasias that were once considered inoperable or hard to reach. Using EEA offers the benefits of no incisions to heal, no disfigurement to the patient, and a shorter recovery time.
Your doctor will perform a physical exam and ask about any symptoms you are experiencing. These symptoms may include head or facial deformities, bone pain, and 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.
Images provided by x-rays, MRI, and/or CT scans can reveal the presence of abnormal tissue in bones and the extent to which bones are affected. A bone scan also may be ordered. 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 malignant. However, this is a rare occurrence.
For more problematic cases involving chronic pain, fractures or deformity, surgery may be necessary. Surgical treatment for fibrous dysplasia involves removal of the affected bone, followed by a bone graft from another part of the body. Stabilizing agents such as metal plates, rods, and screws also may be inserted during surgery.
Fibrous dysplasia of the skull base may be approached directly by using the Endoscopic Endonasal Approach (EEA). This approach allows surgeons to see and access the area well without making incisions to the face or skull. The affected tissue is removed through the nose and nasal cavities, and recovery time is faster than with a traditional approach.
At UPMC, we take a 360° Approach to treatment when evaluating each patient—looking at their conditions from every direction—to find the path that is least disruptive to the patient's brain, critical nerves, and ability to return to normal functioning. Our neurosurgical team may recommend a combination of surgical and non-surgical approaches to maximize the benefits of surgery while minimizing risks.
To preserve sight, surgery for optic nerve decompression is needed in cases where the fibrous dysplasia has caused cranial nerve defects by deforming the optic canal.
