Monostotic fibrous dysplasia.

1. Monostotic fibrous dysplasia in the long bones occurs most frequently in adolescence. In the jaws it is found mainly in early adult life. It presents later in the ribs, probably because it is often asymptomatic in this site. 2. The disease is equally distributed in both sexes. 3. Reactivation may occasionally occur in later life and in pregnancy. 4. Successful surgical treatment is by no means always easily achieved, and requires, in addition to the problems of fracture fixation and the correction of deformity, careful consideration of the age of the patient, the activity of the lesion and the extent to which it involves the cortical bone.