MAXILLARY MALIGNANT MESENCHYMOMA AND MASSIVE FIBROUS DYSPLASIA

This is the first report (to our knowledge) that describes a patient w ith massive polyostotic fibrous dysplasia involving the calvaria and f acial skeleton that subsequently underwent transformation to a maligna nt mesenchymoma with elements of chondrosarcoma, osteosarcoma, and rha bdomyosarcoma arising in the maxilla. Malignant transformation occurre d in the absence of prior radiation exposure, osteomyelitis, or known bony infarction. A review of the literature did not reveal any similar cases of massive fibrous dysplasia of the maxilla degenerating to mul tiple simultaneous malignant histotypes.