Magister Scientiae Dentium - MSc(Dent) / Ossifying fibroma (OF) is the most frequent of the three fibro-osseous lesions of the jaws. It occurs mostly in patients between the age of 20 and 40 years. Females are more commonly affected than males. Clinically, OF usually presents as a painless expansive intra-bony mass. Swelling and pain may be present in some cases while some lesions are discovered incidentally. Radiographically, OF is usually well-defined and unilocular or multilocular. Early lesions present as well-defined radiolucency that are small in size. Over time, the lesions tend to enlarge in size and become mixed radiolucent-radiopaque and finally become completely radiopaque. The aim of this study was to determine the clinical and radiological features of ossifying fibroma presenting at the Departments of Maxillo-Facial and Oral Surgery and Diagnostics and Radiology, University of the Western Cape Oral Health Centre as well as to assess its management and recurrence patterns. A retrospective case series analysis was performed of all histopathologically diagnosed ossifying fibroma cases available at the Departments of Maxillo-Facial and Oral Surgery and Diagnostics and Radiology at the Faculty of Dentistry, University of the Western Cape from 1976-2014. Patient's age, gender and ethnicity were recorded. The clinical presentation of the lesion as well as the history was analyzed. Radiographic features including density, size, shape, location, locularity and its effect on adjacent structures was noted. Management of each case and follow-up was also documented. A total 61 cases were included in the study. The majority of patients were females (63.9%) and below 40 years of age (73.9%). Few cases were symptomatic (29.5%) with an average period 22 months from first symptoms to presentation. The mandibular posterior region was most affected (55.5%) while larger lesions occurred more frequently in younger patients. Majority of lesions were radiopaque (49.2%) and had well-defined margins (93.6%). Most cases were managed by surgical curettage (68.2%). Following an average follow-up period of 20 months only one case recurred (recurrence rate =6.7%). In conclusion, the majority of the clinical and radiographic findings of ossifying fibroma were similar in South African patients as those of other populations. Differences include that the lesions in this population were more radio-opaque and larger in size than in the reported literature. Surgical curettage is an acceptable management protocol with low rate of recurrence.

As lesões fibro-ósseas da região maxilomandibular constituem um grupo heterogêneo de patologias que incluem lesões de desenvolvimento, reativas (displásicas) e neoplásicas, sendo que as duas principais entidades incluídas neste grupo são a displasia fibrosa e o fibroma ossificante. Devido a grande similaridade histológica entre estas patologias a avaliação das características clínicas e imaginológicas, juntamente com os aspectos histopatológicos, são o principal método de diagnóstico diferencial, porém devido a presença de diferentes níveis de maturidade destas patologias, em diversos casos os componentes histológicos assim como seu ordenamento são muito semelhantes. A busca por um processo de diagnóstico histológico mais fundamentado, hoje inexistente, é justificada pela diferença do curso clínico assim como pela eleição do tratamento entre a displasia fibrosa e o fibroma ossificante. Desta forma o propósito deste trabalho foi realizar uma análise retrospectiva descritiva das características clínico-demográficas e histopatológicas, e estabelecer um critério de diagnóstico diferencial que associe algumas características histopatológicas padronizadas juntamente com uma análise imunoistoquímica dos fatores de atividade de remodelação óssea destas lesões. Desta forma foram aplicados diferentes marcadores proteicos e moleculares em casos previamente diagnosticados de displasia fibrosa e fibroma ossificante, objetivando direcionar um critério de diagnóstico mais preciso. Nesse estudo retrospectivo foram avaliados 54 casos, sendo 30 casos de displasia fibrosa e 24 casos de fibroma ossificante, definidos após uma revisão nas análises das lâminas seguindo um padrão com algumas particularidades histomorfológicas para o diagnóstico diferencial. As características histológicas utilizadas para essa diferenciação, baseadas na revisão da literatura, foram: 1- limite entre a lesão e o tecido ósseo adjacente; 2- depósitos esféricos basofílicos (calcificações cementóides); 3- espaços negativos limítrofes entre o tecido ósseo e o tecido conjuntivo; 4- intensidade da celularidade do estroma e; 5- paralelismo das trabéculas ósseas lesionais. Após a reavaliação das lâminas seguindo a padronização de diferenciação com os cinco critérios histológicos mencionados anteriormente, foram reconsiderados os diagnósticos de 7 lâminas, ou seja 12,96% das amostras apresentaram alteração no diagnóstico anatomopatológico inicial. Posteriormente foram utilizados os seguintes imunomarcadores proteicos e moleculares do metabolismo ósseo em 9 lâminas de fibroma ossificante e em 7 lâminas de displasia fibrosa: interleucina 6 (IL-6), osteoprotegerina (OPG), osteocalcina (OCN) e o ligante do receptor do ativador do fator nuclear Kappa B (RANKL). A imunoexpressão destes marcadores foi observada nos seguintes locais: osteócitos, osteoblastos, osteoclastos e no estroma. Apenas a osteoprotegerina apresentou significância estatística nos osteócitos, osteoblastos e osteoclastos. A osteoprotegerina no estroma e os demais marcadores não apresentaram significância estatística em nenhum dos locais. / The fibro-osseous lesions of the maxillomandibular region constitute a heterogeneous group of pathologies that include developmental, reactive (dysplastic) and neoplastic lesions, and the two main entities included in this group are fibrous dysplasia and ossifying fibroma. Due to the great histological similarity between these pathologies the evaluation of the clinical and imaging characteristics, together with the histopathological aspects, are the main method of differential diagnosis, however due to the presence of different levels of maturity of these pathologies, in several cases the histological components as well as their arrangement are very similar. The search for a more substantiated histological diagnosis process, which does not exist today, is justified by the difference in the clinical course as well as by the choice of treatment between fibrous dysplasia and ossifying fibroma. Therefore, the purpose of this study was to perform a descriptive retrospective analysis of the clinical-demographic and histopathological characteristics and to establish a differential diagnosis criterion that associates some standard histopathological characteristics together with an immunohistochemical analysis of the bone remodeling activity factors of these lesions. In this way different molecular and protein markers were applied in previously diagnosed cases of fibrous dysplasia and ossifying fibroma, aiming at directing a more precise diagnosis criterion. In this retrospective study, 54 cases were evaluated, 30 cases of fibrous dysplasia and 24 cases of ossifying fibroma, defined after a review in the analysis of the slides following a pattern with some histomorphological peculiarities for the differential diagnosis. The histological characteristics used for this differentiation, based on the literature review, were: 1- border between the lesion and the adjacent bone tissue; 2- basophilic spherical deposits (cementoid calcifications); 3 - borderline negative spaces between the bone tissue and connective tissue; 4- intensity of stroma cellularity; 5- parallelism of lesionous trabeculae. After the reassessment of the slides following the standardization of differentiation with the five histological criteria mentioned above, the diagnoses of 7 slides were reconsidered, that is, 12.96% of the samples presented alterations in the initial anatomopathological diagnosis. Subsequently, the following protein and molecular biomarkers of bone metabolism were used on 9 ossifying fibrous slides and on 7 fibrous dysplasia slides: interleukin 6 (IL-6), osteoprotegerin (OPG), osteocalcin (OCN) and the activator receptor ligand Of nuclear factor Kappa B (RANKL). Immunoexpression of these markers was observed at the following sites: osteocytes, osteoblasts, osteoclasts and in the stroma. Only osteoprotegerin presented statistical significance in osteocytes, osteoblasts and osteoclasts. The osteoprotegerin in the stroma and the other markers did not present statistical significance in any of the sites.

As lesões fibro-ósseas da região maxilomandibular constituem um grupo heterogêneo de patologias que incluem lesões de desenvolvimento, reativas (displásicas) e neoplásicas, sendo que as duas principais entidades incluídas neste grupo são a displasia fibrosa e o fibroma ossificante. Devido a grande similaridade histológica entre estas patologias a avaliação das características clínicas e imaginológicas, juntamente com os aspectos histopatológicos, são o principal método de diagnóstico diferencial, porém devido a presença de diferentes níveis de maturidade destas patologias, em diversos casos os componentes histológicos assim como seu ordenamento são muito semelhantes. A busca por um processo de diagnóstico histológico mais fundamentado, hoje inexistente, é justificada pela diferença do curso clínico assim como pela eleição do tratamento entre a displasia fibrosa e o fibroma ossificante. Desta forma o propósito deste trabalho foi realizar uma análise retrospectiva descritiva das características clínico-demográficas e histopatológicas, e estabelecer um critério de diagnóstico diferencial que associe algumas características histopatológicas padronizadas juntamente com uma análise imunoistoquímica dos fatores de atividade de remodelação óssea destas lesões. Desta forma foram aplicados diferentes marcadores proteicos e moleculares em casos previamente diagnosticados de displasia fibrosa e fibroma ossificante, objetivando direcionar um critério de diagnóstico mais preciso. Nesse estudo retrospectivo foram avaliados 54 casos, sendo 30 casos de displasia fibrosa e 24 casos de fibroma ossificante, definidos após uma revisão nas análises das lâminas seguindo um padrão com algumas particularidades histomorfológicas para o diagnóstico diferencial. As características histológicas utilizadas para essa diferenciação, baseadas na revisão da literatura, foram: 1- limite entre a lesão e o tecido ósseo adjacente; 2- depósitos esféricos basofílicos (calcificações cementóides); 3- espaços negativos limítrofes entre o tecido ósseo e o tecido conjuntivo; 4- intensidade da celularidade do estroma e; 5- paralelismo das trabéculas ósseas lesionais. Após a reavaliação das lâminas seguindo a padronização de diferenciação com os cinco critérios histológicos mencionados anteriormente, foram reconsiderados os diagnósticos de 7 lâminas, ou seja 12,96% das amostras apresentaram alteração no diagnóstico anatomopatológico inicial. Posteriormente foram utilizados os seguintes imunomarcadores proteicos e moleculares do metabolismo ósseo em 9 lâminas de fibroma ossificante e em 7 lâminas de displasia fibrosa: interleucina 6 (IL-6), osteoprotegerina (OPG), osteocalcina (OCN) e o ligante do receptor do ativador do fator nuclear Kappa B (RANKL). A imunoexpressão destes marcadores foi observada nos seguintes locais: osteócitos, osteoblastos, osteoclastos e no estroma. Apenas a osteoprotegerina apresentou significância estatística nos osteócitos, osteoblastos e osteoclastos. A osteoprotegerina no estroma e os demais marcadores não apresentaram significância estatística em nenhum dos locais. / The fibro-osseous lesions of the maxillomandibular region constitute a heterogeneous group of pathologies that include developmental, reactive (dysplastic) and neoplastic lesions, and the two main entities included in this group are fibrous dysplasia and ossifying fibroma. Due to the great histological similarity between these pathologies the evaluation of the clinical and imaging characteristics, together with the histopathological aspects, are the main method of differential diagnosis, however due to the presence of different levels of maturity of these pathologies, in several cases the histological components as well as their arrangement are very similar. The search for a more substantiated histological diagnosis process, which does not exist today, is justified by the difference in the clinical course as well as by the choice of treatment between fibrous dysplasia and ossifying fibroma. Therefore, the purpose of this study was to perform a descriptive retrospective analysis of the clinical-demographic and histopathological characteristics and to establish a differential diagnosis criterion that associates some standard histopathological characteristics together with an immunohistochemical analysis of the bone remodeling activity factors of these lesions. In this way different molecular and protein markers were applied in previously diagnosed cases of fibrous dysplasia and ossifying fibroma, aiming at directing a more precise diagnosis criterion. In this retrospective study, 54 cases were evaluated, 30 cases of fibrous dysplasia and 24 cases of ossifying fibroma, defined after a review in the analysis of the slides following a pattern with some histomorphological peculiarities for the differential diagnosis. The histological characteristics used for this differentiation, based on the literature review, were: 1- border between the lesion and the adjacent bone tissue; 2- basophilic spherical deposits (cementoid calcifications); 3 - borderline negative spaces between the bone tissue and connective tissue; 4- intensity of stroma cellularity; 5- parallelism of lesionous trabeculae. After the reassessment of the slides following the standardization of differentiation with the five histological criteria mentioned above, the diagnoses of 7 slides were reconsidered, that is, 12.96% of the samples presented alterations in the initial anatomopathological diagnosis. Subsequently, the following protein and molecular biomarkers of bone metabolism were used on 9 ossifying fibrous slides and on 7 fibrous dysplasia slides: interleukin 6 (IL-6), osteoprotegerin (OPG), osteocalcin (OCN) and the activator receptor ligand Of nuclear factor Kappa B (RANKL). Immunoexpression of these markers was observed at the following sites: osteocytes, osteoblasts, osteoclasts and in the stroma. Only osteoprotegerin presented statistical significance in osteocytes, osteoblasts and osteoclasts. The osteoprotegerin in the stroma and the other markers did not present statistical significance in any of the sites.

Die Radiologie fungiert als wesentliches Instrument in der Diagnostik und Nachsorge fibro-ossärer Läsionen (FOL). Hierbei gewinnen überlagerungsfreie, dreidimensionale Aufnahmen aufgrund der im Kopf-Halsbereich vorhandenen hohen Dichte und Vielfalt anatomischer Strukturen und der damit einhergehenden Fülle von Differentialdiagnosen an Bedeutung. Anhand der Studie wurden die röntgenologischen Charakteristika von ossären Dysplasien (OD) und ossifizierenden Fibromen (OF) im dentalen Volumentomogramm herausgestellt, sowie diagnostische und therapeutische Vorteile der dentalen Volumentomographie (DVT) im Vergleich zur Orthopantomographie (OPG) und Computertomographie (CT) ermittelt und gegenübergestellt. Zu diesem Zwecke wurden anhand eines Fragebogens 18 Röntgenbildpaare (OPG-DVT) von FOL durch zehn Betrachter auf (A) deren röntgenologische Eigenschaften sowie Metallartefakte befundet und (B) deren Abbildungsqualität von sehr gut (1) bis schlecht (5) bzw. nicht beurteilbar bewertet. Insgesamt wurden 360 Analysebögen ausgewertet. Entitäts- und röntgentechnikspezifische Unterschiede wurden statistisch ermittelt. Die Abbildungsqualitäten der DVT und CT wurden auf Grundlage einer intensiven Literaturrecherche verglichen. Die Ergebnisse dieser Studie stellten signifikante Unterschiede in den röntgenologischen Eigenschaften von OD und OF heraus. Acht von zehn Strukturen zeigten in den DVT-Aufnahmen eine signifikant bessere Abbildungsqualität im Vergleich zu den OPG-Aufnahmen. Die teilweise gravierenderen Befunde in den DVT-Aufnahmen deuteten auf eine Unterinterpretation dieser Befunde im OPG hin. Die Literaturrecherche zu Gegenüberstellungen der Abbildungsqualitäten in CT und DVT wies nahezu ausnahmslos auf eine Überlegenheit der DVT hin.

Die Radiologie fungiert als wesentliches Instrument in der Diagnostik und Nachsorge fibro-ossärer Läsionen (FOL). Hierbei gewinnen überlagerungsfreie, dreidimensionale Aufnahmen aufgrund der im Kopf-Halsbereich vorhandenen hohen Dichte und Vielfalt anatomischer Strukturen und der damit einhergehenden Fülle von Differentialdiagnosen an Bedeutung. Anhand der Studie wurden die röntgenologischen Charakteristika von ossären Dysplasien (OD) und ossifizierenden Fibromen (OF) im dentalen Volumentomogramm herausgestellt, sowie diagnostische und therapeutische Vorteile der dentalen Volumentomographie (DVT) im Vergleich zur Orthopantomographie (OPG) und Computertomographie (CT) ermittelt und gegenübergestellt. Zu diesem Zwecke wurden anhand eines Fragebogens 18 Röntgenbildpaare (OPG-DVT) von FOL durch zehn Betrachter auf (A) deren röntgenologische Eigenschaften sowie Metallartefakte befundet und (B) deren Abbildungsqualität von sehr gut (1) bis schlecht (5) bzw. nicht beurteilbar bewertet. Insgesamt wurden 360 Analysebögen ausgewertet. Entitäts- und röntgentechnikspezifische Unterschiede wurden statistisch ermittelt. Die Abbildungsqualitäten der DVT und CT wurden auf Grundlage einer intensiven Literaturrecherche verglichen. Die Ergebnisse dieser Studie stellten signifikante Unterschiede in den röntgenologischen Eigenschaften von OD und OF heraus. Acht von zehn Strukturen zeigten in den DVT-Aufnahmen eine signifikant bessere Abbildungsqualität im Vergleich zu den OPG-Aufnahmen. Die teilweise gravierenderen Befunde in den DVT-Aufnahmen deuteten auf eine Unterinterpretation dieser Befunde im OPG hin. Die Literaturrecherche zu Gegenüberstellungen der Abbildungsqualitäten in CT und DVT wies nahezu ausnahmslos auf eine Überlegenheit der DVT hin.