The term, fibrous dysplasia of bone was first used by Lichtenstein in 1938. This is a condition affecting one or more bones, show progress and showing a tendency to become arrested. The etiology is unknown, but it is now believed to be a developmental error in which primitive fibrous tissue proliferates within the bony medulla and encroaches upon the cortex from within. The process may be monostotic or polyostotic. In the latter form, some patient exhibit a remarkable combination of abnormal skin pigmentation and endocrine disturbance. Auther, recently, have observed 2 cases of fibrous dysplasia of maxillary bone which was confirmed as pathologically. One case occurred in 23 years-old male and another in 19 years-old male.