Fibrous dysplasia is a skeletal disorder that affects bone growth and development within the first two decades of life; it destroys and replaces normal bone and is not usually fatal. Although classified as a benign process, local expansion can cause significant functional and aesthetic deformities. The cause of this disease is currently unknown, although protein abnormalities have been suggested. This is a very uncommon disease, which has led to ambiguities regarding incidence; however, it is known that the male-to-female ratio is 2:1.