ABSTRACT
Fibrous dysplasia of bone is an uncommon condition of unknown etiology in which the bones become progressively thicker and lose their normal structure. The skull and the bones in other parts of the body are involed in a process characterized by small areas of bone destruction or massive sclerotic overgrowth. They appear denser, although actually are softer, and give a rather homogenous, smeary impression. There may be cyst like areas within the large, dense, homgenous-appearing amorphous bone. Although the skull may be the only area of involvement it is not uncommon to have similar but more cystic appearing lesions in many other bones. The authors report two cases of fibrous dysplasia involving frontal, orbital roof, ethmoid, zygoma and sphenoid bone in the left by which disfiguration of appearance of the face was resulted in association with exophthalmus.