Fibrous dysplasia is an uncommon bone disease. The diagnosis is usually not difficult, given the symptoms, radiology, and histology. The gene involved is the α subunit of the G-protein receptor. Recent innovation in molecular pathology has helped us understand the mechanism of disease pathogenesis. The treatment of fibrous dysplasia is limited to maintenance of maximum bone density. Surgical reinforcement is used to treat bowing deformities and fractures as they occur. Malignant transformation of fibrous dysplasia is rare. Currently, there is no therapy for preventing the disease from advancing or for malignant transformation.