Fibrous dysplasia is a benign bone lesion characterized by the replacement of the normal substance by fibro-osseous connective tissue, which exhibits varying degrees of osseous metaplasia histologically. The term "fibrous dysplasia" was first used by Lichtenstein in 1938. Fibrous dysplasia is essentially a fibro-osseous malformation affecting one (monostotic type) or more (polyostotic type) bone. The etiology of fibrous dysplasia 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, often producing expansion. Our cases are women, aged 45, 43 and 22, who had monostotic fibrous dysplasia of mandible. For three patients, treatment was performed by widely surgical excision. But, one case (22-year-old woman) recurred 6 years after the initial operation.
