Fibrous dysplasia is a syndrome characterized by dysplastic fibro-osseous skeletal changes. The syndrome has been described in the literature under a number of different terms including osteodystrophia fibrosa, polyostotic osteitis fibrosa, regional fibrocystic disease, osteitis fibrosa cystica, and fibrous dysplasia. The disease has been reported in dogs, horses, swine, monkeys and man.