Answer:
Fibrous dysplasia is a benign pathologic condition of bone in which fibrous tissue gradually expands and replaces normal bone. It is a primary developmental abnormality of bone-forming mesenchyme. The disease usually begins in childhood and progresses throughout puberty and adolescence. Fibrous dysplasia may be monostotic or polyostotic. The physical findings varies depending on the bone involved. Skull involvement occurs in 27 percent of monostotic and up to 50 percent of polyostotic patients. Frontal, orbital, and sphenoid bones are frequently involved. Malignant degeneration of fibrous dysplasia is 0.4 percent, especially in patients with previous radiation treatment.
The mental status of the patient is usually normal but neurologic complications from compression such as fifth nerve impairment, hearing loss, vision loss, and seizure disorders have been reported.
Treatment is aimed at correcting or preventing functional problems and achieving normal facial aesthetics. Conservative shaving or contouring was the policy of treatment before craniofacial surgeons developed techniques for radical excision and reconstruction. Aggressive, radical surgery can prevent recurrence, stop further deformity and functional disturbances.
One area of controversy in the surgical treatment of dealing with fibrous dysplasia is when it occurs in the teeth-bearing areas of the maxilla and mandible. The general consensus has been to treat this area conservatively with shaving. In a recent article from the group at the Craniofacial Center at the Chang Gung Memorial Hospital in Taiwan, PRS Vol 86 (5) 835, 1999, orthognathic surgery is advised when indicated to restore occlusion and correct dentofacial deformity. They report on five cases in which they achieved long-term stability of occlusion and adequate healing in the fibrodysplastic bone using standard fixation.