Radiological Identification of Fibrous Dysplasia of the Jaws

Abstract

Fibrous dysplasia of the jaws has been noted in a number of reports, but a clear and complete picture of its roentgen appearance in the mandible and maxilla has not emerged. This is because the number of cases studied has usually been small or because the jaw involvement was but a part of the general disease and therefore was not presented in detail. This study of 17 histologically proved cases of fibrous dysplasia of the jaw is undertaken, therefore, to formulate a basis for the roentgen identification of that disease. In about 50 per cent of all the patients with fibrous dysplasia referred to us for x-ray consultation, jaw involvement has been the presenting or only manifestation of the disease. In addition to the relative frequency with which the jawbones may be the main site of the process, there are other reasons for considering the roentgen diagnosis of fibrous dysplasia of the jaw in a separate category. The differential diagnosis of jaw lesions, because of the presence of dental elements, is more complicated and specialized than that of lesions of other bones of the face. Difficult technical problems are encountered as well. Furthermore, it is through the dentist or oral surgeon that many conditions involving the jaw first come to light. If he is armed with a thorough knowledge of the roentgen diagnosis of all diseases affecting the jaws, the roentgenologist can bring much of value to this area where his abilities have often not been fully utilized. The roentgen diagnosis of the polyostotic form of fibrous dysplasia is usually easy, and the findings that may be encountered have been thoroughly described in the literature (2, 3, 5, 7, 9, 18). Naturally a thorough knowledge of the appearance of the generalized form of fibrous dysplasia provides the basis for its recognition as a monostotic lesion or one confined principally to the jawbones. Each of the 17 cases in our series was diagnosed pathologically by a member of the Pathology Department of Memorial Center. In approximately two-thirds this diagnosis was unequivocal. In the remainder the opinion was “consistent with fibrous dysplasia.” All doubtful cases were reviewed by Dr. Arthur Allen of the Pathology Department before they were accepted. In a few cases, because the pathological material was somewhat scanty and the diagnosis was not unequivocal, it was only after thorough consideration of the roentgenologic, clinical, and pathologic data that the case was included. Each patient had one or more x-ray studies of the jaw. It is the prevailing thought of the Department of Pathology that, while closely similar and at times indistinguishable from each other, ossifying fibroma and fibrous dysplasia often present minor distinguishing histological features. Certainly in the greater part of this material the diagnosis was unquestionably fibrous dysplasia. The same was true of the material used previously for a study of the roentgen diagnosis of ossifying fibroma (12).