Current concepts of craniofacial fibrous dysplasia: pathophysiology and treatment

Fibrous dysplasia is an uncommon genetic disorder in which bone is replaced by immature bone and fibrous tissue, manifesting as slow-growing lesions. Sporadic post-zygotic activating mutations in GNAS gene result in dysregulated GαS-protein signaling and elevation of cyclic adenosine monophosphate in affected tissues. This condition has a broad clinical spectrum, ranging from insignificant solitary lesions to severe disease. The craniofacial area is the most common site of fibrous dysplasia, and nine out of 10 patients with fibrous dysplasia af-fecting the craniofacial bones present before the age of 5. Surgery is the mainstay of treatment, but the technique varies according to the location and severity of the lesion and associated symptoms. The timing and indications of surgery should be carefully chosen with multi-disciplinary consultations and a patient-specific approach. Abbreviations: BMSC, bone marrow stromal cell; cAMP, cyclic adenosine monophosphate; CT, computed tomography; FD, fibrous dyspla-sia; GH, growth hormone; MAS, McCune-Albright syndrome; MRI, magnetic resonance imaging.