[Differential diagnosis in fibro-osseous lesions of facial bones: report of a case of ossifying fibroma and review of literature].

Ossifying fibroma is a relatively rare, benign neoplasm of non-odontogenic origin, affecting the facial bones, and prevalently localized in the mandible, but which can also appear in the maxilla, paranasal sinuses and peripheral bones. Its growth is generally very slow and it is usually asymptomatic, for which it often manages to reach a considerable size. An incidental diagnosis during orthopantography, on the other hand, is not infrequent. The diagnosis, which is fundamentally made by utilizing conventional x-rays and CT and NMR scans, may present several controversial aspects and is not to be disjointed from the clinical and anatomopathological aspects, for which close interdisciplinary collaboration is required in many cases. In effecting a differential diagnosis, the possibility of inflammatory lesions, other fibrous-osseous lesions (in particular, fibrous dysplasia) and benign or malignant neoplasms must be taken into consideration. The present work presents a case of ossifying fibroma of the maxilla that is emblematic in its clinical, radiological and histopathological aspects. It also discusses problems connected with classification and differential diagnosis, in particular with respect to fibrous dysplasia, which are important in determining the proper therapeutic approach.