Assessment of MDM2 Gene Locus Amplification by Fluorescence In-Situ Hybridization in Juvenile Ossifying Fibroma.

Juvenile ossifying fibroma (JOF) is an uncommon benign fibro-osseous lesion (BFOL) of the maxillofacial bones with a locally aggressive nature and a high recurrence rate. Murine Double Minute 2 (MDM2) is an oncogene located at chromosome 12 (12q13-15) that inhibits the tumor suppressor gene TP53. The presence of MDM2 gene locus amplification is a useful molecular adjunct in the evaluation of some sarcomas, including low-grade intramedullary osteosarcoma (LGIOS). JOF and LGIOS have some overlapping clinical and histopathological features. The aim of this study is to evaluate a series of JOF for the presence of MDM2 gene locus amplification using fluorescence in-situ hybridization (FISH). MATERIALS AND METHODS: With IRB approval, a search of the institutional files of the archives of the Oral Pathology and Surgical Pathology biopsy services at the University of Florida Health was performed. The cases were re-evaluated by an oral pathology resident, an oral and maxillofacial pathologist, and a bone and soft tissue pathologist. Cases with consensus in diagnosis were selected (n = 9) for MDM2 testing. Testing by FISH for MDM2 gene locus amplification was applied to all retrieved cases. RESULTS: The examined cases were all negative for MDM2 gene locus amplification via FISH testing. CONCLUSION: In our small series, JOF did not demonstrate MDM2 gene locus abnormality, a characteristic of LGIOS. This finding suggests that JOF has a distinct underlying pathogenesis. If confirmed in a larger series, these findings may be useful in distinguishing these two entities in cases with overlapping features or when minimal biopsy material is available.

Ossifying fibroma: the peripheral variant.

Introduction: Peripheral ossifying fibroma (POF) is a solitary gingival growth thought to arise from the gingiva, periosteum or the periodontal ligament. It is a slow-growing, benign, progressive lesion that is limited in size. Case description: This article describes a case of ossifying fibroma of a peripheral variant that occurred in a 26-year-old female in the anterior region of the lower jaw and presented as a growth on the gingiva. Since it was difficult to diagnose clinically, a pathological evaluation was mandatory. Upon pathological confirmation of the diagnosis, the lesion was surgically excised up to the periosteum. This was deemed to be the required treatment yet, since the recurrence rate is high for POF (8% to 20%), the patient must be followed up yearly to check for recurrence.

Introduction: Le fibrome ossifiant périphérique (FOP) est une excroissance gingivale solitaire dont on pense qu'elle provient des gencives, du périoste ou du ligament parodontal. Il s'agit d'une lésion progressive, bénigne et à croissance lente dont la taille est limitée. Description du cas: Cet article décrit le cas d'une variante périphérique du fibrome ossifiant survenue chez une femme de 26 ans, dans la région antérieure de sa mâchoire inférieure et se présentant comme une excroissance sur la gencive. Comme il était difficile d'établir un diagnostic clinique, une évaluation pathologique a été nécessaire. Après confirmation pathologique du diagnostic, la lésion a été excisée jusqu'au périoste lors d'une opération chirurgicale. On a jugé ce traitement nécessaire, puisque le taux de récidive du FOP est élevé (entre 8 % et 20 %). La patiente doit faire l'objet d'un suivi annuel pour rechercher toute récidive éventuelle.

Prevalence of Histopathologic Types of Gingival Lesions in the Iranian Population: A 22-Year Retrospective Study.

OBJECTIVES: Gingiva is one of the supporting tissues around the teeth that can be affected by various neoplastic or nonneoplastic lesions. Previous studies have examined several types of gingival lesions, but the lack of a standardized classification system has hindered meaningful comparisons. Additionally, many studies focused primarily on reactive lesions. Our study aims to contribute to the understanding of gingival lesions by investigating their prevalence across age groups, genders, sites, and by their clinical presentation. This research could lead to improved diagnostic accuracy and treatment strategies. MATERIALS AND METHODS: This retrospective study explores the prevalence of gingival lesions based on biopsies during a 22-year span. The patient's demographic details, including age, gender, and lesion's clinical presentation were systematically collected. These lesions were categorized into six groups. Descriptive statistics, χ2 test of independence, and one-way ANOVA were used for data analysis. RESULTS: Among the 7668 biopsied lesions, 684 (8.9%) lesions were located in the gingiva, with a greater occurrence in women (63.5%). Soft tissue tumors represented the most prevalent group in the gingival lesions (72.1%), and peripheral giant cell granuloma (PGCG) was the most frequent lesion (21.2%), followed by, pyogenic granuloma (19.3%), peripheral ossifying fibroma (17.8%) and focal fibrous hyperplasia (7.6%); all of which predominantly affected women, with mean ages falling in the fourth decade of life. Squamous cell carcinoma was recognized as the most common malignancy. CONCLUSION: In this study, PGCG was found to be the most common lesion in the gingiva in Iranian population. Further analysis using a unanimous categorization is required to confirm these results.

A giant peripheral ossifying fibroma of the maxilla with extreme difficulty in clinical differentiation from malignancy: a case report and review of the literature.

BACKGROUND: Peripheral ossifying fibroma is a nonneoplastic inflammatory hyperplasia that originates in the periodontal ligament or periosteum in response to chronic mechanical irritation. Peripheral ossifying fibroma develops more commonly in young females as a solitary, slow-growing, exophytic nodular mass of the gingiva, no more than 2 cm in diameter. While various synonyms have been used to refer to peripheral ossifying fibroma, very similar names have also been applied to neoplastic diseases that are pathologically distinct from peripheral ossifying fibroma, causing considerable nomenclatural confusion. Herein, we report our experience with an unusual giant peripheral ossifying fibroma with a differential diagnostic challenge in distinguishing it from a malignancy. CASE PRESENTATION: A 68-year-old Japanese male was referred to our department with a suspected gingival malignancy presenting with an elastic hard, pedunculated, exophytic mass 60 mm in diameter in the right maxillary gingiva. In addition to computed tomography showing extensive bone destruction in the right maxillary alveolus, positron emission tomography with computed tomography revealed fluorodeoxyglucose hyperaccumulation in the gingival lesion. Although these clinical findings were highly suggestive of malignancy, repeated preoperative biopsies showed no evidence of malignancy. Since even intraoperative frozen histological examination revealed no malignancy, surgical resection was performed in the form of partial maxillectomy for benign disease, followed by thorough curettage of the surrounding granulation tissue and alveolar bone. Histologically, the excised mass consisted primarily of a fibrous component with sparse proliferation of atypical fibroblast-like cells, partly comprising ossification, leading to a final diagnosis of peripheral ossifying fibroma. No relapse was observed at the 10-month follow-up. CONCLUSIONS: The clinical presentation of giant peripheral ossifying fibromas can make the differential diagnosis from malignancy difficult. Proper diagnosis relies on recognition of the characteristic histopathology and identification of the underlying chronic mechanical stimuli, while successful treatment mandates complete excision of the lesion and optimization of oral hygiene. Complicated terminological issues associated with peripheral ossifying fibroma require appropriate interpretation and sufficient awareness of the disease names to avoid diagnostic confusion and provide optimal management.

Imaging of Fibro-osseous Lesions and Other Bone Conditions of the Jaws.

This review directs the focus on the imaging features of various fibro-osseous lesions and other bone lesions that can be of similar presentation. Broad diagnosis of "fibrous osseous lesion" may culminate in improper treatment and management. Radiographic discriminating factors between these entities are highlighted and summarized to improve the diagnostic process when encountering these lesions.

Hybrid tumor of central giant cell granuloma and trabecular juvenile ossifying fibroma of the mandible: A rare event in the oral cavity with a review on pathogenesis.

ABSTRACT: Hybrid tumors are rare lesions having features of multiple diseases in one lesion. A hybrid tumor of central giant cell granuloma (CGCG) and central ossifying fibroma (COF) shows the presence of microscopically large areas with CGCG character and large areas with COF features inside a single clinical lesion, separated by a transition zone. A rare type of COF is juvenile ossifying fibroma (JOF)-trabecular variant in the mandible. We present a unique and rare case of a hybrid tumor of the CGCG-JOF-trabecular variant in the mandible of a 14-year-old female which initially diagnosed with CGCG. The ambiguous pathogenesis of hybrid tumors and giant cells is reviewed. The goal of this article is to highlight the importance of careful clinical, radiological, and histopathological examination of each case to prevent misdiagnoses and recurrences. Similar and other cases must be reported in order to better understand the interrelationship between these hybrid lesions and their biological behavior.

Ossifying fibromyxoid tumor: A rare case report with review of literature and its differential diagnosis.

ABSTRACT: Ossifying fibromyxoid tumor (OFMT) is a rare mesenchymal tumor of uncertain histogenesis with intermediate malignant potential presenting commonly in the fifth to sixth decade in the proximal limb and limb girdle. A 65-year-old male patient presented with a slow-growing gluteal mass. Wide local excision performed showed a well-defined tumor in the subcutaneous plane with a partially hard outer shell. Microscopy showed a moderately cellular tumor having cords and nests of round to ovoid cells with moderate cytoplasm and bland nuclei embedded in a myxo-hyaline matrix. An incomplete peripheral rim of ossification was seen. Pleomorphism/high cellularity was not seen. Mitosis was <2/50 high-power field. On immunohistochemistry, both S100 and desmin were positive. A diagnosis of typical OFMT was rendered. Even though rare with many morphological mimics, OFMT should be diagnosed with precision as most of these tumors are low-grade tumors that require only wide local excision and close follow-up without any adjuvant therapy.

Histomorphometric and molecular characterization of stromal and mineralized components in fibro-osseous lesions.

BACKGROUND: Indistinct and analogous histopathological features of various fibro-osseous lesions make establishing a definitive diagnosis a challenge. There is a need for additional molecular and histochemical tools to support and differentiate these lesions in order to establish a concrete diagnosis. MATERIALS AND METHODS: A retrospective analysis of biopsied lesions in formalin-fixed paraffin-embedded sections (10 cases each of fibrous dysplasia, ossifying fibroma, and cement-osseous dysplasia) retrieved from the archives was studied for immunoexpression of osteocalcin (quantitative analysis in osteocytes), collagen characterization using Azan, Picrosirus, and Toluidine blue stain for evaluating intensity and localization of collagen fibers, and morphometric analysis of vasculature (for evaluating mean vessel density as square microns). RESULTS: Positive immunostaining of osteocalcin suggested mutations of the GNAS-1 gene found in fibrous dysplasia indirectly, as it is a negative regulator of bone formation. Osteocalcin immunopositivity was quantitatively measured in the fibro-osseous lesions, with fibrous dysplasia measuring 14.47 ± 3.628 as compared to ossifying fibroma measuring 5.23 ± 1.33, followed by cemento-osseous dysplasia measuring 2.30 ± 1.409. Toluidine blue suggests the presence of oxytalan fibers (resistant to acid hydrolysis) in ossifying fibroma and cemento-osseous dysplasia, pointing toward the pathogenesis of the lesion. Azan stain and Picrosirus (under a polarizing microscope) helped in distinguishing hard tissue characteristics (70% of cases of fibrous dysplasia showed only a magenta component followed by intermixed magenta with a blue component in 20% of cases and only 10% of cases showed magenta with blue borders whereas for ossifying fibroma, 40% of cases depicted magenta with blue borders along with the other 40% with intermixed magenta with blue component). The mean vessel density was also highest in fibrous dysplasia measuring 7.90 ± 1.079 (in Sq. micron area), followed by ossifying fibroma and cemento-osseous dysplasia. CONCLUSION: The diagnosis of fibro-osseous lesions by hematoxylin and eosin alone is confusing and thus should be supported by relatively simple histomorphometric analysis for better treatment outcomes. At the diagnostic stage of fibro-osseous lesions, evaluation of intralesional vessel size, reliable molecular marker, and histochemical nature can aid in differentiating fibrous dysplasia from central ossifying fibroma and cemento-osseous dysplasia alongside, other clinical, radiographic and pathological criteria. These parameters help in the diagnostic decision-making of fibro-osseous lesions.

Immunohistochemical analysis of osteoclastic and osteoblastic activity in ossifying fibroma and juvenile ossifying fibroma: A comparative study.

Cemento-ossifying fibroma (COF) and juvenile ossifying fibroma (JOF) have been considered distinct entities within the category of fibro-osseous lesions. This study aimed to assess osteoblast and osteoclast activity in COF and JOF by investigating bone resorption markers, specifically receptor activator of nuclear factor-kB (RANK), RANK ligand (RANKL), and its inhibitor osteoprotegerin (OPG). A comparative analysis of these markers was performed on all lesions. Immunohistochemistry was employed to evaluate and quantify the expression of these biomarkers in a sample of 20 cases of cemento-ossifying fibroma (COF), 15 cases of psammomatoid juvenile ossifying fibroma (PsJOF), and 10 cases of trabecular juvenile ossifying fibroma (TrJOF). The expression of osteoprotegerin was significantly higher in cemento-ossifying fibroma (33.9±13.0) compared to trabecular juvenile ossifying fibroma (27.3±9.2) and psammatoid ossifying fibroma (25.2±14.9), with the COF showing the highest expression followed by the latter two (p=0.037). There was a higher percentage (80%) of stromal fibroblast cells that showed positive expression of RANKL in cemento-ossifying fibroma (COF) compared to psammomatoid juvenile ossifying fibroma (PsJOF) (33.3%) and trabecular juvenile ossifying fibroma (TrJOF) (30.0%) when considering a positive expression score of 3 (p=0.024). Cemento-ossifying fibroma demonstrated the highest expression of osteoprotegerin and RANKL-positive stromal fibroblast cells, followed by psammomatoid juvenile ossifying fibroma and trabecular juvenile ossifying fibroma. These findings provide valuable insights into the pathogenesis of these lesions.

Extraosseous cemento-ossifying fibroma beneath the left buccal mucosa: a case report.

Cemento-ossifying fibroma (COF) is a benign mesenchymal odontogenic tumor that commonly occurs in the tooth-bearing areas of the maxilla and mandible. This study reports a COF case located under the left buccal mucosa. The classification and differential diagnosis of this COF case were discussed based on the diagnosis and treatment of this case and previous literature.

Cemento-ossifying fibroma resection combined with heterotopic canine autotransplantation: a case report.

Cemento-ossifying fibroma (COF) is a mesenchymal benign odontogenic tumor, which may lead to impacted or ectopic permanent teeth. Autotransplantation of teeth is a surgical process, in which a tooth is transplanted from one position to another in the same individual. This method can effectively restore the patient's mastication and aesthetics and is feasible in replacing missing teeth. This study reports a case of simultaneous COF resection combined with heterotopic canine autotransplantation to repair dentition defect, which effectively promotes the restoration of bone continuity and stability and achieves immediate and long-term aesthetic function requirements.

Ossifying Fibroma of Mandible - A Case Report.

INTRODUCTION: Ossifying fibromas are rare, non-aggressive benign tumours of the bone, commonly involving the posterior mandible in middle-aged individuals with a female predilection. FINDINGS: Clinical manifestations include asymptomatic expansion of the mandible with infrequent maxillary lesions, pain, malocclusion, and compromised quality of life including aesthetic perception. Owing to multiplicity of features, tendency of recurrence, and possibility of malignant transformation, the diagnosis, treatment, and post-operative management of ossifying fibroma are always a challenge. TAKEAWAY LESSONS: Study aims to report a clinical case of extensive swelling involving the coronoid process and condyle on the right side to crossing the mid-line of the mandible with compromised functions and aesthetics. The article describes the clinical, histopathological, and radiological features of the case. The possible treatment and challenges encountered are discussed.

Clinical and pathological features and differential diagnosis of fibro-osseous tumors and dysplasias / 中华口腔医学杂志

Fibro-osseous lesions is a class of diseases with obvious similarities in clinical manifestations and pathological features, which has been attracting the attention of clinicians and pathologists. The latest WHO 2022 Classification (5th edition) included six of these diseases (cemento-osseous dysplasia, segmental odontomaxillary dysplasia, fibrous dysplasia, juvenile trabecular ossifying fibroma, psammomatoid ossifying fibroma and familial gigantiform cementoma) in the " fibro-osseous tumours and dysplasias ", and put forward new ideas on the diagnosis and treatment of these diseases. According to the latest WHO 2022 Classification (5th edition), the clinical and pathological features, diagnosis and differential diagnosis of these six diseases were described.

Peripheral ossifying fibroma: A 20-year retrospective studywith focus on clinical and morphological features

Background: Peripheral Ossifying Fibroma (POF) is a reactive hyperplastic lesion that exclusively occurs in thegingiva and is characterized by the deposition of dystrophic calcification, cementum-like tissue, and immatureand mature bone within the connective tissue. The objective of the present study was to perform a retrospectiveanalysis of clinicopathologic features of POF.Material and Methods: Clinical and histopathological data were obtained from biopsy records and histopathological reports from a Brazilian reference service in Oral Pathology (1999 - 2020). Morphological analysis wasperformed to evaluate features related to the mesenchymal component, inflammatory infiltrate, ulceration, andmineralized tissue.Results: A total of 270 POFs were diagnosed during the study period. A higher frequency was observed in females(71.9%) between the third (22.9%) and fourth (23.3%) decades of life. The anterior upper gingiva (29.1%) wasthe most affected region. Mature (86.7%) and immature (52.6%) bone tissue were the most frequent. There was asignificant association between immature bone deposition and lesions with size ≤ 1.7 cm (p = 0.041); immaturebone and cement-like tissue deposition with an evolution time ≤ 16 months (p < 0.001); deposition of immaturebone and mesenchymal hypercellularization (p < 0.001); deposition of dystrophic calcification and the presenceof ulceration (p < 0.001).Conclusions: The clinical characteristics corroborate the findings in the literature. The heterogeneous distributionand quantity of mineralized tissues found in the analyzed cases support the theory that the different mineralizedtissues constitute a spectrum of clinical maturation of POF. (AU)

Tumor fibromixoide osificante maligno supraclavicular / Supraclavicular malignant ossifying fibromyxoid tumor

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O Cripto-1 é um potencial biomarcador para o diagnóstico diferencial dos tumores ósseos benignos e malignos dos maxilares / Cripto-1 is a potential biomarker for the differential diagnosis of benign and malignant jaw bone tumors

O termo lesão fibro-óssea dos maxilares (LFOM) é uma designação inespecífica para um grupo de distúrbios caracterizados, morfologicamente, pela substituição do tecido ósseo por uma matriz de tecido conjuntivo fibrosa, a qual exibe neoformação de tecido ósseo com diferentes graus de mineralização. O diagnóstico preciso das LFOM não é fácil e só pode ser realizado após uma análise minuciosa dos aspectos clínicos, radiológicos e histológicos. No entanto, deve-se admitir que alguns casos desafiam a exatidão na emissão do diagnóstico. Considerando a diversidade do comportamento biológico das lesões e as pesquisas sobre a identificação de potenciais marcadores moleculares, o objetivo deste trabalho foi realizar uma análise imunohistoquímica do cripto-1 (CR-1) e da ß-catenina em uma série de casos diagnosticados microscopicamente como displasia fibrosa (DF) (n=30), fibroma ossificante central (FOC) (n=28) e osteossarcoma (OS) (n=5) armazenados nos arquivos do Serviço de Anatomia Patológica Oral de uma população brasileira. As expressões imuno-histoquímicas foram analisadas através de escore imunorreativo. Os dados obtidos foram inseridos em um arquivo do software Microsoft Excel® e, posteriormente, analisados no software Statistical Package for Social Science. Para todos os testes estatísticos utilizados, o nível de significância foi estabelecido em 5% (p<0,05). O CR-1 exibiu predominância de um padrão fortemente positivo para os casos de FOC e OS, e do padrão moderado para os casos de DF (p<0,001). A ß-catenina exibiu predominância do padrão negativo para os casos de FOC e DF, e do padrão fortemente positivo para os casos de OS (p=0,001). O teste de correlação de Spearman revelou correlação positiva entre os escores imunorreativos de CR-1 e ß-catenina. Os resultados desta pesquisa sugerem a participação do CR-1 na patogênese do FOC e OS, assim como o uso dessa proteína como potencial biomarcador molecular para o diagnóstico diferencial de LFOM (AU).

Fibro-osseous lesions of maxilar (FOLM) is a non-specific designation for a group of disorders characterized, morphologically, by replacement of bone tissue by a matrix of fibrous connective tissue, showing neoformation of bone tissue with varying degrees of mineralization. Precise diagnosis of FOLM is not easy, and requires careful analyisis of clinical, radiological and histological aspects. Even so, some cases still challenge accuracy in diagnosis. Considering the diversity of biological behaviour of the lesions and the research regarding identification of potential molecular markers, this study aims to perform immunohistochemical analysis of crypto-1 and ß-catenin in a series of cases diagnosed microscopically as fibrous dysplasia (FD) (n=30), central ossifying fibroma (COF) (n=28) and osteossarcoma (OS) (n=5), stored in archives of Oral Pathological Anatomy Service of a Brazilian population. Immunohistochemical expressions were analysed by imunorreactive score. All data obtained was inserted into a file of Microsoft Excel® software (Microsoft Corporation, USA) and then transferred to a database of SPSS® for Windows software (Statistical Package for Social Sciences; IBM, USA), version 20.0. For all statistical tests used, the significance level established was p ≤ 0.05. CR-1 showed a predominant pattern of strong positive in COF and OS cases, and a moderate positive in FD cases (p<0,001). ß-catenin showed a predominant negative pattern for COF and FD cases, and a predominant strong positive pattern for OS cases (p=0,001). Spearman correlation tests showed positive correlation of the imunoreative scores of CR-1 and ß-catenin. Those results suggests CR-1 could be involved in the pathogenesis of COF and OS, and this protein could be used as a potential molecular biomarker for diferential diagnosis of FOLM (AU).

Incidence of reactive hyperplastic lesions in the oral cavity: a 10 year retrospective study in Santa Catarina, Brazil / Incidência de lesões hiperplásicas reativas na cavidade bucal: estudo retrospectivo de 10 anos em Santa Catarina, Brasil

Abstract Introduction Reactive hyperplastic lesions develop in response to a chronic injury simulating an exuberant tissue repair response. They represent some of the most common oral lesions including inflammatory fibrous hyperplasia, oral pyogenic granuloma, giant cell fibroma, peripheral ossifying fibroma, and peripheral giant cell lesions. Objective The incidence of those lesions was investigated in an oral pathology service, and the clinical characteristics, associated etiological factors, concordance between the clinical and histopathological diagnostic was determined. Methods A total of 2400 patient records were screened from 2006 to 2016. Clinical features were recorded from biopsy reports and patients' files. Results A total of 534 cases of reactive hyperplastic lesions were retrieved and retrospectively studied, representing 22.25% of all diagnoses. The most frequent lesion was inflammatory fibrous hyperplasia (72.09%), followed by oral pyogenic granuloma (11.79%), giant cell fibroma (7.30%), peripheral ossifying fibroma (5.24%), and peripheral giant cell lesions (3.55%). Females were predominantly affected (74.19%), the gingiva and alveolar ridge were the predominant anatomical site (32.89%), and chronic traumatism was presented as the main etiological factor. The age widely ranges from the 1st decade of life to the 7th. Clinically, the reactive hyperplastic lesions consisted of small lesions (0.5-2 cm) and shared a strong likeness in color to the oral mucosa. The concordance between the clinical and histopathological diagnostic was high (82.5%). Conclusion Reactive hyperplastic lesions had a high incidence among oral pathologies. The understanding of their clinical features helps to achieve a clearer clinical and etiological diagnosis, and the knowledge of factors related to their development. This may contribute to adequate treatment and positive prognosis.

Resumo Introdução As lesões hiperplásicas reativas se desenvolvem em resposta a uma lesão crônica que estimula uma resposta acentuada de reparo tecidual. Elas representam uma das lesões orais mais comuns, inclusive hiperplasia fibrosa inflamatória, granuloma piogênico oral, fibroma de células gigantes, fibroma periférico ossificante e lesão periférica de células gigantes. Objetivo A incidência dessas lesões foi investigada em um serviço de patologia bucal e as características clínicas, os fatores etiológicos associados e a concordância entre os diagnósticos clínico e histopatológico foram determinados. Método Foram selecionados 2.400 registros de pacientes entre 2006 e 2016. As características clínicas foram registradas a partir de laudos de biópsia e dos prontuários dos pacientes. Resultados Um total de 534 casos de lesões hiperplásicas reativas foram recuperados e retrospectivamente estudados, representando 22,25% de todos os diagnósticos. A lesão mais frequente foi hiperplasia fibrosa inflamatória (72,09%), seguida por granuloma piogênico oral (11,79%), fibroma de células gigantes, (7,30%), fibroma periférico ossificante (5,24%) e lesão periférica de células gigantes (3,55%). O sexo feminino foi predominante (74,19%), a gengiva e a crista alveolar foram o local anatômico predominante (32,89%) e o traumatismo crônico foi demonstrado como o principal fator etiológico. A idade variou desde a 1ª década de vida até a 7ª. Clinicamente, as LHR consistiram em pequenas lesões (0,5 a 2 cm) que apresentaram uma forte semelhança de cor com a mucosa oral. A concordância entre o diagnóstico clínico e histopatológico foi alta (82,5%). Conclusão As lesões hiperplásicas reativas apresentaram alta incidência entre as patologias bucais. A compreensão das características clínicas ajuda na realização de um diagnóstico clínico e etiológico mais claro, bem como determinar os fatores relacionados ao seu desenvolvimento. Dessa forma contribui para um tratamento adequado e um prognóstico positivo.

Fibroma ossificante periférico ­ Relato longitudinal de dois casos clínicos / Long-term follow-up of peripheral ossifying fibroma ­ report of two cases

O fibroma ossificante periférico é uma lesão não neoplásica proliferativa, não patognomônico, de evolução lenta e indolor, que acomete os tecidos gengivais. O presente trabalho teve como objetivo relatar dois casos clínicos desta lesão em um acompanhamento em longo prazo, ressaltando os aspectos clínicos e histopatológicos, bem como seu tratamento e prognóstico.

The peripheral ossifying fibroma is a non-neoplasic, proliferative lesion of painless and slow evolutive character, which involves the gingival tissues. This paper reports on two clinical cases in a long-term follow-up highlightening their clinical and histopathologic aspects, treatment, and outcomes.

The role of Osterix protein in the pathogenesis of peripheral ossifying fibroma

Abstract Peripheral ossifying fibroma (POF) is a reactive lesion of oral tissues, associated with local factors such as trauma or presence of dental biofilm. POF treatment consists of curettage of the lesion combined with root scaling of adjacent teeth and/or removal of other sources of irritants. This study aimed to analyze the clinical and pathological features of POF and to investigate the immunoexpression of Osterix and STRO-1 proteins. Data such as age, gender, and size were obtained from 30 cases of POF. Microscopic features were assessed by conventional light microscopy using hematoxylin-eosin staining and immunohistochemical markers, and by polarized light microscopy using Picrosirius red staining. The age range was 11-70 years and 70% of the patients were female. Moreover, the size of POF varied from 0.2 to 5.0 cm; in 43.33% of the cases, the mineralized content consisted exclusively of bony trabeculae. The immunohistochemical analysis showed nuclear staining for Osterix in 63% and for STRO-1 in 20% of the cases. Mature collagen fibers were observed in mineralized tissue in 76.67% of the cases. The clinical and microscopic features observed were in agreement with those described in the literature. Osterix was overexpressed, while STRO-1 was poorly expressed. Osterix was expressed particularly in cells entrapped in and around mineralized tissue, indicating the presence of a stimulus that triggers the differentiation of these cells into osteoblasts or cementoblasts, i.e., cells that produce mineralized tissue. Based on our results, Osterix may play a role in the pathogenesis of POF.