Clinicopathological analysis of fibrous dysplasia and central ossifying fibroma of the jaws: an international collaborative study

Author(s)

Ana Carolina Prado Ribeiro

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2011-09-16

Examining board members

Pablo Agustin Vargas; Ana Maria Pires Soubhia; Elaine Maria Sgavioli Massucato; Decio dos Santos Pinto Junior; Márcio Ajudarte Lopes

• Advisor: Pablo Agustin Vargas

Abstract

Fibrous dysplasia (FD) and ossifying fibroma (OF) comprehend a group of benign fibro-osseous lesions (BFOL) which mainly affects the maxilla, mandible and craniofacial bones. They are characterized by the replacement of normal bone tissue by a matrix of fibrous connective tissue with varying degrees of mineralization. Both lesions frequently share clinical and microscopic features and the final diagnose require a combined analysis of clinical, radiologic and histological data. There might be significant cosmetic and functional impairment despite having a distinct pattern of progression and biological behavior, therefore, it is important to distinguish them from each other at the final diagnose. This research focused on the study and comparison of the demographic, clinical, imaging and microscopic aspects of patients with FD and OF, at the moment of the diagnostics. A retrospective multiinstitucional research was conducted in which there were 68 FD cases and 37 of OF. Characteristics such as gender, age and anatomic site of the tumor samples were obtained from the medical records. FDs (n=41; 60,2%) and OFs (n=24; 64,9%) were more frequently detected in female patients who were at the second or third decade of life. The maxilla was more prominently affected among the FD cases (n=38; 56%) contrasting to the prevalence of the mandible in the OF cases (n=23 62.2%). According to the radiographic aspects, FDs frequently presented as radiopaque lesions, with ill-defined limits, and OFs had well defined margins and were radiolucid. Microscopically, a continuity of the lesion with the bone cortical was evident in the FDs, as well as a separation phenomenon between the bone trabeculae and the surrounding connective tissue of the adjacent stroma. In OFs, the discontinuity of the lesion with the bone cortical was noticed, so were the presence of cement-like structures. In conclusion, the diagnose of FD and OF must be done based on the sum of the clinical, radiographic and microscopic features, although it was possible to observe a few peculiar characteristics in each one of them, which might serve as a diagnostic tool and therefore improve the treatment of the patients (AU)