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Purpose Benign fibro-osseous lesions (BFOLs) are heterogeneous intraosseous disease processes sharing overlapping histopathologic features and demonstrate a wide range of biological behavior. The aim of this study is to highlight the importance of clinical and radiological findings for the definitive histopathologic diagnosis of benign fibro-osseous lesions of the jaws. Materials and Methods This is a cross-sectional retrospective study evaluating the three main groups of BFOLs: Cemento-osseous dysplasia, ossifying fibromas, and fibrous dysplasia. Previously diagnosed BFOL cases were searched for thoroughly from the archives of Istanbul University, Institute of Oncology, Department of Tumor Pathology in between 2005 and 2015. Clinical and radiological data of these cases were identified and recorded. The histopathologic features were reevaluated from the H&E-stained slides. Results A total of 276 BFOL cases were identified and reevaluated for the study. The most common BFOL type was cemento-osseous dysplasia (n = 135), followed by cemento-ossifying fibroma (n = 77), fibrous dysplasia (n = 53) and juvenile ossifying fibroma (n = 11). The female/male ratio was 3.4:1 with a strong predilection for the 4th decade (n = 102). The mandible (n = 209) was the predominantly affected jaw. Prominent osteoblastic rimming around the bony lesion was commonly observed for cemento-ossifying fibroma (n = 60/77), followed by cemento-osseous dysplasia (n = 23/135). Predominant ossification patterns showed some differences among the groups. The most common radiological feature was the mixed radiolucent/radiopaque internal structure. Conclusion Our results document various clinical, radiological and histopathologic findings of BFOLs. Even some histopathologic differences are observed, clinical and radiographic correlation is mandatory prior to the definitive histopathologic diagnosis of BFOLs for the prevention of possible misdiagnoses or inappropriate treatments.

Objectives Nevoid Basal Cell Carcinoma Syndrome (NBCS) is a rare genetic condition affecting multiple organs including the maxillofacial and dental region. The surgical removal of the odontogenic keratocystic tumors (OKT), the high rate of recurrence leads to a iatrogenic tooth loss requiring dental care. The aim of this study is therefore to describe the dental and orthodontic management, and to assess the impact of surgery on facial growth and oral development. Methods A retrospective study including 14 patients with GGS, followed at the Necker Enfants Malades Hospital. The study was carried out on the medical files and photographic records Results Patients developed on average 5.5 OKT (range: 1 to 11) and 1.7 recurrences (range:0 to 9) during the follow-up. The mean age at diagnosis of first OKT was 11.23 years (range: 6.75 to 16). KOTs were more frequently localized at the mandibular (30.9%) and maxillary molar level (25.1%). Forty-seven impacted teeth were extracted during the OKT removal. Eight patients out of 12 presented a class III skeletal relationship. The remaining ones had a skeletal class II associated with a hyperdivergent typology. Almost all patients had dental impactions with ectopic positions of the succedaneums tooth. At the inter-arch level, all patients needed orthodontic care, 3 patients did not begin their orthodontics. Orthodontic treatments began with an orthopedic phase followed by braces for the majority in 8 patients. Two patients had to undergo orthognathic surgery. Impacted teeth were treated by traction or extraction with further rehabilitation. Conclusion The objective is not to simply compensate the iatrogenic hypodontia generated by the surgical procedure but to take into consideration the maxillofacial phenotype, skeletal characteristics and numerous intra- and inter-arch dental anomalies for a healthy oral management.

Objectives The objective of this study was to demonstrate the clinical, radiologic, and histologic features of orthokeratinized odontogenic cyst (OOC); determine the characteristics of multiple OOCs; and present rare but significant manifestations of OOC. Study Design A clinical, radiologic, and histopathologic study of 65 primary and 2 recurrent OOC cases was performed retrospectively along with a comprehensive literature review. Results OOCs shared similar radiologic findings with odontogenic keratocyst, yet some showed features that have not been previously described: root resorption and radiopaque foci. Histologic review revealed a unique histiocytic lining and some findings suggestive of the multipotentiality of the odontogenic epithelium. The analysis of patients with multiple OOCs demonstrated that multiple OOCs occurred synchronously with a marked predilection for young male adults. Two unusual cases were also identified: an OOC combined with a BRAFV600E ameloblastoma and a recurrent OOC with malignant transformation. Conclusions This largest series presents previously unreported radiographic and histopathologic features that can be seen in OOC. Multiple OOCs have clinical characteristics distinct from those of solitary cases. The first reported OOC associated with ameloblastoma suggests the involvement of oncogenic mutations in odontogenic tumorigenesis. Although OOC shows a low recurrence rate, the possibility of malignant transformation of recurrent OOCs should be emphasized.

Introduction The classification of odontogenic tumors has been revised from time to time in order to provide unified terminology. This reclassification had considerable impact on their prevalence and frequency distribution. Objectives This study was aimed to emphasize impact of changing classification systems on prevalence and relative frequency of odontogenic tumors. The secondary objective was to analyze demographics of various histological types of odontogenic tumors in comparison to published literature. Review of Indian studies (1992-2020) elaborating frequency of odontogenic tumors is summarized in the end. Methods This was a hospital-based retrospective study wherein case files of odontogenic tumors diagnosed from 1990 to 2019 period were retrieved. The classification system used originally at the time of diagnosis was retained and prevalence of odontogenic tumors in three different periods (1990-2004, 2005-2016 and 2017-2019) was compared. Further, prevalence, frequency distribution and demographics of all these tumors (1990-2019) were analyzed using latest World Health Organization 2017 classification. Results A total of 345 odontogenic tumors was diagnosed as per World Health Organization 2017 system of classification from 1990 to 2019. 96.81% tumors were benign and 3.81% constituted malignant odontogenic tumors. However, there was marked increase in prevalence of odontogenic tumors in 2005-2016 (6.2%) period as compared to 1990-2004 (3.87%) and 2017-2019 (3.47%). Ameloblastoma remained the most common tumor in three different periods, whereas keratocystic odontogenic tumor became second commonest tumor in 2005-2016 as compared to odontoma in 1990-2004 and adenomatoid odontogenic tumor in 2017-2019. Conclusions The continuous evolving systems of classification may partly be responsible for inconsistency in odontogenic tumors, with inclusion of keratocystic odontogenic tumor,and has marked impact on prevalence and frequency distribution of odontogenic tumors. The geographical variations in demographics of odontogenic tumors might reflect genetic and environment influence; however it requires elucidation by further studies. Resumo Introdução A classificação dos tumores odontogênicos é revisada de tempos em tempos para fornecer uma terminologia unificada. Essas revisões tiveram um impacto considerável na prevalência e distribuição da frequência desses tumores. Objetivo Enfatizar o impacto da mudança dos sistemas de classificação na prevalência e frequência relativa dos tumores odontogênicos. O objetivo secundário foi analisar os dados demográficos de vários tipos histológicos de tumores odontogênicos em comparação com a literatura publicada. A revisão dos estudos indianos (1992-2020) sobre a frequência dos tumores odontogênicos é resumida no fim. Método Este foi um estudo retrospectivo com base em registro hospitalar de casos de tumores odontogênicos diagnosticados de 1990‐2019 que foram revisados. O sistema de classificação usado originalmente no momento do diagnóstico foi mantido e a prevalência de tumores odontogênicos em três períodos (1990-2004, 2005-2016 e 2017-2019) foi comparada. Além disso, a prevalência, a distribuição da frequência e os dados demográficos de todos esses tumores (1990-2019) foram analisados com a classificação mais recente da OMS de 2017. Resultados Foram diagnosticados 345 tumores odontogênicos de acordo com o sistema de classificação da OMS (2017) de 1990-2019. A ocorrência de tumores odontogênicos benignos e malignos foi de 96,81% e 3,81%, respectivamente. Contudo, houve um aumento acentuado na prevalência de tumores odontogênicos de 2005‐2016 (6,2%), comparado aos períodos de 1990‐2004 (3,87%) e 2017‐2019 (3,47%). O ameloblastoma permaneceu como o tumor mais comum em três períodos, enquanto o tumor odontogênico ceratocístico passou a ser o segundo tumor mais comum em 2005‐2016, comparado ao odontoma em 1990‐2004 e ao tumor odontogênico adenomatoide em 2017‐2019. Conclusões Os sistemas de classificação em evolução contínua podem, em parte, atribuir uma inconsistência à classificação dos tumores odontogênicos com a inclusão do tumor odontogênico ceratocístico e causar um impacto marcante na prevalência e distribuição da frequência dos tumores odontogênicos. As variações geográficas na demografia dos tumores odontogênicos podem refletir influências genéticas e ambientais, mas requerem elucidação por estudos futuros.

The odontogenic keratocyst (OKC) is a potentially aggressive odontogenic lesion and there is an ongoing debate regarding its biological behavior and classification. The present systematic review aims to assess the expression of the p53 protein in the odontogenic keratocyst in comparison to the dentigerous cyst and ameloblastoma. We searched MEDLINE, Web of Science and Scopus for immunohistochemical studies reporting OKC's, dentigerous cysts and solid/multicystic ameloblastomas. The Risk Difference between the lesions expressing the p53 was the effect measure and a P value

BACKGROUND Although pathology in the maxillary and mandibular bones is rare in young patients, the differential diagnosis is broad. The World Health Organization (WHO) updated its classification of maxillofacial bone pathology in 2017. Using these updated guidelines, a systematic review of common maxillofacial bone lesions in the pediatric population was performed. METHODS A PubMed search was conducted capturing English language articles from inception to July 2020. Thirty-one articles were identified that described the frequency of maxillofacial bone pathology. Data were extracted and organized using the WHO 2017 classification of odontogenic and maxillofacial bone tumors. Prevalence data were analyzed among diagnostic categories and geographical regions. The SAS version 9.4 was used to complete statistical analyses. RESULTS The articles included patients from birth to a maximum age of 14 to 19 years. The most common odontogenic cysts included radicular cyst (42.7%) and dentigerous cyst (39.0%) followed by odontogenic keratocyst (15.0%). Among odontogenic bone tumors, odontoma (49.3%) was most common followed by ameloblastoma (29.1%). The most common nonodontogenic bone tumor was fibrous dysplasia (42.4%), and the most common malignant bone tumor was osteosarcoma (75.0%). Significant variations were found by geographic region, with dentigerous cyst more common than radicular cyst, and ameloblastoma more common than odontoma in African and Asian countries (P

BACKGROUND Cyclooxygenase-2 protein is a critically important mediator in inflammation that influences proliferation, apoptosis, angiogenesis and metastasis. Previous works showed a relationship between cyclooxygenase-2 and tumourigenesis in humans and animal models. In epithelial odontogenic tumours and cysts, increased cell proliferation and survival have been linked to its pathogenesis and tumour development. The aim of the present study was to analyse the immunohistochemical expression of cyclooxygenase-2 in solid ameloblastoma and odontogenic keratocyst and its association with proteins related to cell proliferation and apoptosis. METHODS This study was conducted on 40 cases from the Pathological Anatomy Service, University of Chile. The cases were diagnosed as solid ameloblastoma (n = 21) and odontogenic keratocyst (n = 19) according to WHO 2017. Slides prepared from paraffin-embedded sections were immunohistochemically stained for cyclooxygenase-2, cyclin D1, Ki-67, p63 and Bcl-2. Statistical evaluation was performed by the Shapiro-Wilk test, ANOVA Mann-Whitney test and Spearman's correlation coefficient (p

Objective The aim of this study was to report the clinicopathologic features of 105 new cases of adenomatoid odontogenic tumor (AOT) from Brazil, Guatemala, Mexico, and South Africa. Study Design Clinical and radiographic data were collected from records of 5 oral pathology laboratories, and all cases were microscopically reviewed. Results This series of cases included 36 (34.2%) from South Africa; 33 (31.4%) from Brazil; 23 (21.9%) from Mexico; and 13 (12.3%) from Guatemala. Seventy-two patients (68.5%) were females and 33 patients (31.4%) were males, with an average age of 19.2 years. The tumors predominantly affected the anterior maxilla (48.5%), followed by the anterior mandible (29.5%); posterior mandible (15.2%); and posterior maxilla (6.6%). Sixty-three tumors (63.6%) were follicular, 34 (34.3%) were extrafollicular, and 2 (2%) were peripheral. In most cases, the tumors caused considerable cortical expansion (average size 3.4 cm). Microscopically, most cases showed rosette-like and duct-like structures. Conclusions This is one of the largest case series of AOTs reported in the literature and the first multicenter study involving populations from Latin America and South Africa. In a fifth of the present cases, the posterior regions of the gnathic bones were affected and the tumors demonstrated larger sizes compared with cases occurring in other populations.

Glandular tumors of jaw bones present, most often, histopathologic features of salivary gland and, rarely, of cutaneous glandular neoplasms. They are thought to originate from odontogenic epithelium. An unusual maxillary tumor presenting as a radiolucency in the periapical area of the right permanent lateral incisor of a 74-year-old male is presented causing root resorption. Preparations revealed occasionally branching tubular cords and ductal structures characterized, mostly, by a bilayer composed of luminal cuboidal to low columnar cytokeratin (CK) 7, Ber-EP4 and occasionally CK8/18 positive cells, and abluminal, CK5/6 positive, basal/basaloid cells revealing nuclear reactivity for p63/p40. Smooth muscle actin and calponin were negative, save for a single focus of calponin positive cells, confirming absence of myoepithelial support or epithelial mesenchymal transition. CK19 exhibited staining of both layers, the luminal being more intense. Eosinophilic secretory material and, occasionally, a luminal pellicle were decorated with CK8/18 and polyclonal carcinoembryonic antigen (CEA). CD1a identified only rare Langerhans’ cells and Ki67 decorated 1–2% of abluminal cell nuclei. Small solid nests of epithelial cells were also present. Infrequently, an apparent transition of a nest into a tubular structure was appreciated. The partially inflamed stroma featured multiple hyalinized acellular deposits consistent with amyloid, as confirmed by bright orange Congo red reactivity with apple-green birefringence, which reacted with odontogenic ameloblast-associated (ODAM) protein antibody but not with antibodies for amelotin and secretory calcium-binding phosphoprotein proline-glutamine rich 1. Based on the above, the diagnosis of tubuloductal/syringoid variant of central odontogenic fibroma with ODAM amyloid is favored.

The Inhibitor of Growth (ING) gene family is a group of tumor suppressor genes that play important roles in cell cycle control, senescence, DNA repair, cell proliferation, and apoptosis. However, inactivation and downregulation of these proteins have been related in some neoplasms. The present study aimed to evaluate the immunohistochemical profiles of ING3 and ING4 proteins in a series of benign epithelial odontogenic lesions. Methods: The sample comprised of 20 odontogenic keratocysts (OKC), 20 ameloblastomas (AM), and 15 adenomatoid odontogenic tumors (AOT) specimens. Nuclear and cytoplasmic immunolabeling of ING3 and ING4 were semi-quantitatively evaluated in epithelial cells of the odontogenic lesions, according to the percentage of immunolabelled cells in each case. Descriptive and statistics analysis were computed, and the p-value was set at 0.05. Results: No statistically significant differences were found in cytoplasmic and nuclear ING3 immunolabeling among the studied lesions. In contrast, AOTs presented higher cytoplasmic and nuclear ING4 labeling compared to AMs (cytoplasmic p-value = 0.01; nuclear p-value < 0.001) and OKCs (nuclear p-value = 0.007). Conclusion: ING3 and ING4 protein downregulation may play an important role in the initiation and progression of more aggressive odontogenic lesions, such as AMs and OKCs. Resumo Objetivos: A família dos Genes Inibidores de Crescimento (ING) é um grupo de genes supressores tumorais que desempenham papéis importantes no controle do ciclo celular, na senescência, no reparo do DNA, na proliferação celular e na apoptose. No entanto, a inativação e a regulação negativa dessas proteínas têm sido relacionadas em algumas neoplasias. O objetivo do presente estudo foi avaliar o perfil imuno-histoquímico das proteínas ING3 e ING4 em uma série de lesões odontogênicas epiteliais benignas. Métodos: A amostra foi composta por espécimes de 20 ceratocistos odontogênicos (CO), 20 ameloblastomas (AM) e 15 tumores odontogênicos adenomatoides (TOA). A imunoexpressão nuclear e citoplasmática de ING3 e ING4 foram avaliadas semi-quantitativamente nas células epiteliais das lesões odontogênicas, de acordo com a porcentagem de células imunomarcadas em cada caso. As análises descritivas e estatísticas foram computadas, e o valor de p estabelecido foi de 0,05. Resultados: Não foram encontradas diferenças estatisticamente significativas na imunoexpressão citoplasmática e nuclear de ING3 entre as lesões estudadas. Em contrapartida, os TOAs apresentaram maior marcação citoplasmática e nuclear de ING4 em comparação aos AMs (valor de p citoplasmático=0,01; valor de p nuclear

An improved understanding of the computed tomographic (CT) features for malignant versus benign oral tumors would be helpful for guiding prognosis and treatment planning decisions in dogs. This retrospective, multi-center, observational study compared the CT features of malignant and benign tumors in 28 dogs with 31 oral masses. Malignant tumors were present in 20 dogs, including malignant melanoma (n = 14), squamous cell carcinoma (SCC, n = 4), adenocarcinoma (n = 1), and fibrosarcoma (n = 1). Eight dogs had benign tumors, including giant cell granuloma (n = 2), peripheral odontogenic fibroma (n = 2), acanthomatous ameloblastoma (n = 2), plasmacytoma (n = 1), and oncocytoma (n = 1). Common CT features of malignant tumors included heterogeneous enhancement, tumor invasion into the adjacent bone, tooth loss, and ipsilateral mandibular lymphadenopathy. Malignant tumors were significantly larger than benign tumors. Bone lysis was found in benign tumors (n = 4) such as acanthomatous ameloblastoma, giant cell granuloma, and plasmacytoma. The bone lysis was a well-defined geographic area regardless of malignancy and tumor type. In periosteal reactions, amorphous patterns were seen in both malignant (n = 2) and benign tumors (n = 2); the latter subgroup also showed solid patterns. Bone expansion (n = 2) was identified in malignant melanoma and acanthomatous ameloblastoma. Findings supported a diagnosis of possible malignancy for dogs with oral tumors having the following CT characteristics: large size, heterogeneous contrast enhancement pattern, bone lysis, tooth loss, and ipsilateral lymphadenopathy. However, there was a considerable overlap of CT findings among the different types of oral tumors and between benign and malignant tumors. Histological evaluation therefore remains necessary for definitive diagnosis.

Background Aberrant expression of stem cell markers has been observed in several types of neoplasms. This trait attributes to the acquired stem-like property of tumor cells and can impact patient prognosis. The objective of this study was to comparatively analyze the expression and significance of SOX2 and OCT4 in various types of odontogenic cysts and tumors. Methods Fifty-five cases of odontogenic cysts and tumors, including 15 ameloblastomas (AM), 5 adenomatoid odontogenic tumors (AOT), 5 ameloblastic fibromas (AF), 5 calcifying odontogenic cysts (COC), 10 dentigerous cysts (DC) and 15 odontogenic keratocysts (OKC) were investigated for the expression of SOX2 and OCT4 immunohistochemically. Results Most OKCs (86.7 %) and all AFs expressed SOX2 in more than 50 % of epithelial cells. Its immunoreactivity was moderate-to-strong in all epithelial cell types in both lesions. In contrast, SOX2 expression was undetectable in AOTs and limited to the ameloblast-like cells in a minority of AM and COC cases. Most DCs showed positive staining in less than 25 % of cystic epithelium. Significantly greater SOX2 expression was noted in OKC compared with DC or AM, and in AF compared with COC or AOT. OCT4 rarely expressed in odontogenic lesions with the immunoreactivity being mild and present exclusively in OKCs. Conclusions SOX2 is differentially expressed in odontogenic cysts and tumors. This could be related to their diverse cells of origin or stages of histogenesis. The overexpression of SOX2 and OCT4 in OKC indicates the acquired stem-like property. Future studies should investigate whether the overexpression of OCT4 and SOX2 contributes to the aggressive behaviors of the tumors.

Introduction The adenomatoid odontogenic tumor is a relatively uncommon odontogenic neoplasm representing about 4.7% of all odontogenic tumors. Objective The aim of this study was to determine the demographic and clinical profile of the adenomatoid odontogenic tumors in a Sri Lankan population. Methods Data gathered from the cases received for a period of 38 years from the Department of Oral Pathology, Faculty of Dental Sciences, University of Peradeniya. Request forms, biopsy reports and electronic data base of the department were used to obtain relevant information. Demographic data including age, gender and location of the tumor were included in the analysis. Results Out of 116 cases of adenomatoid odontogenic tumor, the mean age was 21.02 ± 11.24. It occurs more fre quently in the second decade of life, more prevalent in females, most often associated with the maxilla, predominantly affecting anterior jaw bones and presenting mostly in the right side of the jaw bone. The results from the present study showed the statistically significant relationship with site of occurrence (maxilla/mandible) and age (p< 0.005). Further, depending on whether it occurs in anterior/mid/posterior site also showed a significant relationship with age (p≤ 0.001). However, side of occurrence, left or right or site of occurrence, showed no statistically significance with age (p> 0.05). Conclusion Adenomatoid odontogenic tumor occurs more frequently in the second decade of life with a significant female predominance and the commonest site is anterior maxilla. This study revealed few differences on demographic and clinical presentations of adenomatoid odontogenic tumor from some regions of the world. Resumo Introdução O tumor odontogênico adenomatoide é uma neoplasia odontogênica relativamente incomum que representa cerca de 4,7% de todos os tumores odontogênicos. Objetivo Determinar o perfil demográfico e clínico dos tumores odontogênicos adenomatoides em uma população do Sri Lanka. Método Os dados foram obtidos dos casos tratados por 38 anos no Departamento de Patologia Oral da Faculty of Dental Sciences, University of Peradeniya. Formulários de solicitação, relatórios de biópsia e o banco de dados eletrônico do departamento foram usados para obter informações relevantes. Dados demográficos, idade, sexo e localização do tumor foram incluídos na análise. Resultados Dos 116 casos de tumor odontogênico adenomatoide, a média de idade foi de 21,02 ± 11,24. Ocorreu com mais frequência na segunda década de vida, e foi mais prevalente no sexo feminino, mais frequentemente associado à maxila, afetou predominantemente os ossos da mandíbula anterior e apresentou-se principalmente no lado direito dos ossos da mandíbula. Os resultados do presente estudo mostraram uma relação estatisticamente significante com o local da ocorrência (maxila/mandíbula) e idade (p < 0,005). Além disso, de acordo com o local de ocorrência, região anterior/média/posterior, também apresentou relação significante com a idade (p ≤ 0,001). Entretanto, nem o lado acometido, direito ou esquerdo, ou o sítio de ocorrência foi estatisticamente significante em relação à idade (p > 0,05). Conclusão O tumor odontogênico adenomatoide ocorre com mais frequência na segunda década de vida, com predominância feminina significativa, e o local mais comum é a maxila anterior. Este estudo revelou poucas diferenças nas apresentações demográficas e clínicas do tumor odontogênico adenomatoide de algumas regiões do mundo.

Cementoblastomas are rare odontogenic tumors developing in close proximity to the roots of teeth. Due to their striking morphologic resemblance to osteoblastomas of the peripheral skeleton, we set out to determine whether cementoblastomas harbor the same FOS rearrangements with overexpression of c-FOS as has recently been described for osteoblastomas. In total, 16 cementoblastomas were analyzed for FOS expression by immunohistochemistry and for FOS rearrangements by fluorescence in situ hybridization (FISH). We observed strong and diffuse staining of c-FOS in 71% of cementoblastomas and identified a FOS rearrangement in all cases (n=3) applicable for FISH. In the remaining cases, FISH failed due to decalcification. Cementoblastomas harbor similar FOS rearrangements and show overexpression of c-FOS like osteoblastomas, suggesting that both entities might represent parts of the spectrum of the same disease.

Objective The aim of this study was to report the clinicopathologic features of 62 cases of central odontogenic fibroma (COdF). Study Design Clinical and radiographic data were collected from the records of 13 oral pathology laboratories. All cases were microscopically reviewed, considering the current World Health Organization classification of tumors and were classified according to histopathologic features. Results There were 43 females and 19 males (average age 33.9 years; range 8–63 years). Clinically, COdF lesions appeared as asymptomatic swellings, occurring similarly in the maxilla (n = 33) and the mandible (n = 29); 9 cases exhibited palatal depression. Imaging revealed well-defined, interradicular unilocular (n = 27), and multilocular (n = 12) radiolucencies, with displacement of contiguous teeth (55%) and root resorption (46.4%). Microscopically, classic features of epithelial-rich (n = 33), amyloid (n = 10), associated giant cell lesion (n = 7), ossifying (n = 6), epithelial-poor (n = 3), and granular cell (n = 3) variants were seen. Langerhans cells were highlighted by CD1a staining in 17 cases. Most patients underwent conservative surgical treatments, with 1 patient experiencing recurrence. Conclusions To the best of our knowledge, this study represents the largest clinicopathologic study of COdF. Most cases appeared as locally aggressive lesions located in tooth-bearing areas in middle-aged women. Inactive-appearing odontogenic epithelium is usually observed within a fibrous/fibromyxoid stroma, occasionally exhibiting amyloid deposits, multinucleated giant cells, or granular cells.

Background: The process of odontogenesis is complex involving epithelial–mesenchymal interactions, along with the molecular signaling pathways triggering the initiating process. The triggering factors and cells precisely involved in the pathogenesis of odontogenic cysts and tumors are unknown. There is a vast array of biomarkers used to stain different sites, thereby helpful in diagnosing and evaluating the prognosis of these cysts and tumors. Cytokeratins are the intermediate filament proteins which maintain cell integrity and alter their properties in cysts and tumors. In the following study, cytokeratin 19 expression patterns are assessed quantitatively in reduced enamel epithelium, dentigerous cyst and unicystic ameloblastoma. Aim: The aim of present study is to assess expression of CK 19, a stem cell marker in reduced enamel epithelium, dentigerous cyst and unicystic ameloblastoma, quantitatively. Materials and Methods: The present study is carried out with 15 samples in each group. Reduced enamel epithelium is derived from the patients undergoing treatment for impacted teeth. Histopathologically diagnosed cases of dentigerous cyst and unicystic ameloblastoma were considered for the study. With the help of Olympus BX 43 microscope, with ProgRes microscope camera, the 45 slides obtained were examined. The region of interest was selected in each slide and number of cells positively stained was counted. Data were analyzed using SPSS software version 23. Descriptive for scale data, One way anova with post hoc Tukey's test for intergroup comparison. Results: The results showed significant P value

Calcifying odontogenic cysts (COC) and adenomatoid odontogenic tumors (AOT) have similar radiographic findings. We examined the radiographic and computed tomography (CT) images of patients histologically diagnosed with COC or AOT and identified their characteristic findings. The subjects included 12 patients histologically diagnosed with COC or AOT (one female and five males per group), who underwent CT at our hospital between Nov 1998 and Jun 2019. The location of the lesion, impacted tooth, bone expansion, root resorption, tooth migration, calcified body, and presence or absence of a high-intensity zone in the marginal area of the lesion were examined. In patients with COC, five patients with COC exhibited bone expansion toward the buccal side. The lesion encompassing the crown was attached to the cement-enamel junction and contained a radiopaque lesion with a calcified body. In 6 patients with COC, irregularly shaped calcified bodies were observed with small tooth-like structures. In patients with AOT, all six patients with AOT exhibited bone expansion toward the buccal and lingual sides. The lesion encompasses a part of the tooth root or the entire tooth. Punctate calcification was observed within the lesion and the marginal area in three patients, and a high-intensity zone was observed in the marginal area of the lesion in two patients. We report imaging findings that may be characteristic of COC and AOT, suggesting that CT findings may be useful for differentiating between COC and AOT.

A periapical radiopacity is frequently encountered by chance on a conventional periapical or panoramic x-ray. However, local pain and/or swelling in the area of a radiopacity is seldom seen. Here, we report on 2 cases of patients referred to the oral and maxillofacial surgeon with a painful periapical radiopacity in the lower jaw. The clinically and radiologically assumed diagnosis was a cementoblastoma, which was confirmed by histopathological examination following its surgical removal. A cementoblastoma is a rare, benign odontogenic tumor, mostly found in patients younger than 30. Treatment consists of surgical removal of the tumor, almost always together with the attached tooth. The recurrence rate after complete removal is approximately 12%. A cementoblastoma is clinically distinguished from other periapical radiopacities by local pain and sometimes swelling and radiologically by a relationship with the roots of a (pre)molar, a radiolucent rim surrounding the opacity, bone and/or root resorption and expansive growth.Een periapicale radiopaciteit wordt met enige regelmaat bij toeval gevonden op een conventionele intraorale of panoramische röntgenopname. Lokale pijn en/of zwelling in de regio van een radiopake afwijking wordt hierbij zelden gezien. Twee patiënten werden naar een mka-chirurg verwezen vanwege een pijnlijke periapicale radiopaciteit in de onderkaak. De klinische en radiologische vermoedelijke diagnose was een cementoblastoom. Dit werd bevestigd door histopathologisch onderzoek van de chirurgische verwijderde tumor. Het cementoblastoom is een zeldzame goedaardige dentogene tumor, die meestal voor het dertigste levensjaar wordt gediagnosticeerd. De behandeling bestaat uit het chirurgisch verwijderen van de tumor met vrijwel altijd het daarmee verbonden gebitselement. De kans op recidief na volledige verwijdering bedraagt ongeveer 12%. Het cementoblastoom onderscheidt zich klinisch van andere periapicale radiopaciteiten door lokale pijn en soms zwelling en radiologisch door relatie met de wortels van een gebitselement, een radiolucente rand, bot- en/of radixresorptie en expansieve groei.

Ameloblastoma is a benign odontogenic tumor which undergoes malignant transformation to ameloblastic carcinoma. However, rarely it metastasizes without undergoing cytological malignant changes, an entity referred to as Metastasizing Ameloblastoma (MA). Through this study, we aimed to review cases of MA reported since 2000 to explore the impact of clinico-demographic variables on its prognosis. Based on PRISMA guidelines, a review of relevant literature from PubMed/Medline, Science Direct and Cochrane database was performed from January 2000 to March 2019. A total of 65 cases were considered for further evaluation as per predefined inclusion and exclusion criteria. Results showed that lungs followed by lymph nodes were the most common sites for benign metastatic deposits. Multiple recurrences and inadequate surgical removal increase the probability of distant metastatic spread. Despite having benign cytological features, tumor recurrence and metastasis were associated with an unfavorable clinical outcome in MA.

Odontogenic tumors comprised of complex heterogeneous lesions that diverse from harmatomas to malignant tumors with different behavior and histology. The etiology of odontogenic tumors is not exactly determined and pathologists deal with challenges in diagnosis of odontogenic tumors because they are rare and obtained experiences are difficult to evaluate. In this study, we describe immunohistochemical and molecular markers in diagnosis of odontogenic tumors besides advanced diagnostic technique. Immunohistochemical features of odontogenic tumors beside the clinical features and radiological finding can help us to determine the correct diagnosis. Although these markers are neither specific nor sensitive enough, but analysis of gene expression provides definitive confirmation of diagnosis. In addition, “-omics” technology detected specific molecular alternation associated with etiology such as genomics, epigenomics, transcriptomics, proteomics and metabolomics. The post transcriptional events such as DNA methylation and chromatin remodeling by histone modification affect the changes in epigenome. Furthermore, non-coding RNAs like micro-RNAs, long noncoding RNA (lncRNA) and small non-coding RNA (snoRNA) play regulatory role and impact odontogenesis. Molecular marker propose their potential role in etiopathogenesis of odontogenic tumors and suitable candidate in diagnostic, prognostic and therapeutic approaches in addition to patient management. For future evaluations, organoid represents in vitro tumor model-study for tumor behavior, metastasis and invasion, drug screening, immunotherapy, clinical trial, hallmarks association with prognosis and evolution of personalized anti-cancer therapy. Moreover, organoid biobank help us to check genetic profile. We think more investigation and studies are needed to gain these knowledges that can shift therapeutic approaches to target therapy.

Ghost cell odontogenic carcinoma (GCOC) is a rare malignant neoplasm characterized by the presence of ghostcells. It is considered to originate from either a calcifying odontogenic cyst (COC) or a dentinogenic ghost cell tumor(DGCT). Its clinical and radiographic characteristics are non-specific, including slow growth, locally aggressivebehavior, and eventual metastasis. This case report describes a 43-year-old Thai man with plain radiographs and cone-beam computed tomographic images revealing a unilocular radiolucency with non-corticated borders surrounding an impacted left canine associated with radiopaque foci around the cusp tip. Based on the microscopic findings, the lesion was diagnosed as GCOC. Partial maxillectomy of the right maxilla was performed, and radiotherapy was administered. An obturator was made to support masticatory functions Three years later, the lesion showed complete boneremodeling and no signs of recurrence, and long-term follow-up was done regularly.

Purpose Squamous odontogenic tumor (SOT) is a rare, benign, locally infiltrative odontogenic tumor of the gnathic bones. It is composed of islands of bland, well-differentiated squamous epithelium of varying shape and size. Because of histologic overlap, SOT has often been overdiagnosed as ameloblastoma and squamous cell carcinoma. It thus becomes important to understand the clinical, radiologic, histopathologic, and treatment characteristics of this tumor. Materials and Methods Using the PubMed and Google Scholar databases, we searched for reported cases of SOT published in the English-language literature. We were able to retrieve 49 acceptable cases and perform a comprehensive literature review of the intraosseous SOTs, with emphasis on their clinical, radiographic, and pathologic characteristics, as well as treatment strategies. In addition, we present an additional case of SOT affecting the posterior mandible in a 44-year-old female patient. Results The tumor in the posterior mandible in our patient was accompanied by acute pain and treated by enucleation. Histopathologic evaluation showed variably sized islands of benign squamous epithelium scattered in a fibrous stroma, consistent with the diagnosis of an SOT. Uneventful healing was noted at the 1-month postoperative appointment. However, the patient was lost to long-term follow-up. Our literature review showed that the average age at the time of diagnosis of SOT is 34.2 years. Men and women are equally affected, and the tumor does not show a predilection for either jaw bone. The most common locations are the anterior maxilla and posterior mandible. Most SOTs are treated conservatively by enucleation or curettage, whereas aggressive or recurrent tumors require radical resection. Conclusions Careful evaluation of the excised specimen, with immunohistochemical investigations, may prove rewarding in differentiating an SOT from other odontogenic neoplasms and thus minimize the patient's chances of undergoing an unnecessary aggressive intervention.

Primordial odontogenic tumor (POT) is a recently designated benign mixed epithelial and mesenchymal odontogenic tumor and only sixteen cases have been reported worldwide till now. Here we report an another case of POT in a 14–year old boy who presented with an asymptomatic buccal enlargement in the right maxillary region for past 4–5 months. A well-defined, unilocular, radiolucent lesion with impacted teeth was observed radiographically. A detailed account of clinico-radiographical and histolological differential diagnoses along with an updated literature review has been presented.

Odontomas are benign odontogenic tumors formed from epithelial and mesenchymal cells. They are mostly associated with disorders of tooth eruption, causing impaction and/or delayed tooth eruption, and are an accidental finding on routine radiological examination. The aim of this paper is to present current findings in the etiology and treatment of odontomas, as well as the clinical and radiographic features, describing a case that is rarely found in the literature. A case of multiple complex odontoma in the mandible of an 11-year-old boy is presented, causing impaction of the first permanent right molar, 46. The treatment consisted of surgical enucleation of the multiple complex odontoma with preservation of the impacted tooth, monitoring clinically and radiologically its spontaneous eruption followed by final orthodontic alignment. Odontomas are not an everyday part of clinical practice and given that they are most commonly associated with permanent tooth impaction, it is extremely important to have knowledge of their clinical and radiological features. Early diagnostics and appropriate treatment result in better diagnosis, thus increasing the possibility of preserving the impacted teeth., Odontomi su dobroćudni odontogeni tumori nastali od epitelne i mezenhimne osnove. Najčešće su povezani s poremećajima u nicanju zuba, uzrokujući impakciju i/ili zakašnjelo nicanje zuba te su slučajan nalaz prilikom rutinskih radioloških snimaka. Cilj ovoga rada je prikazati dosadašnja saznanja u etiologiji i liječenju odontoma, kao i kliničke i radiografske značajke, prikazujući slučaj koji se rijetko može naći u literaturi. Prikazan je slučaj višestruko složenog odontoma u mandibuli 11-godišnjaka, što uzrokuje impakciju prvog trajnog desnog kutnjaka, 46. Liječenje se sastojalo od kirurške enukleacije višestruko složenog odontoma uz očuvanje zahvaćenog zuba. Nakon operativnog zahvata klinički i radiološki se pratilo spontano nicanje impaktiranog zuba do konačnog ortodontskog ispravljanja položaja zuba. Odontomi nisu svakodnevni dio kliničke prakse, a s obzirom na to da su najčešće povezani s impakcijom trajnih zuba veoma je važno poznavati njihove kliničke i radiološke značajke. Rano dijagnosticiranje i primjereno liječenje rezultiraju boljom dijagnozom, povećavajući tako mogućnost očuvanja impaktiranih zuba.

Background Several nonendodontic diseases can occur in the periapical region, resembling endodontic inflammatory conditions. Therefore, the aim of the present study was to determine the frequency of nonendodontic periapical lesions diagnosed in a Brazilian population. Material and Methods The files of two Oral Pathology laboratories were reviewed and all cases including at least one clinical diagnosis of endodontic periapical lesions were selected for the study. After initial selection, demographic and clinical data, clinical diagnosis and final diagnosis were reviewed and tabulated. Final diagnosis included endodontic periapical lesions, and benign and malignant nonendodontic periapical lesions. Data were descriptively and comparatively analyzed among the three groups, with a significance level of 5% (p0.05). Conclusions The frequency of nonendodontic periapical lesions was high and, although the general distribution was similar to the results from other populations, some features were probably associated with the profile of the studied populations and to the methods applied in the present study. Knowledge on differential diagnosis of endodontic and nonendodontic periapical lesions is essential to avoid unnecessary treatments and diagnostic delay in routine dental practice. Key words:Differential diagnosis, nonendodontic, periapical lesion, pulp necrosis.

Introduction Sclerosing odontogenic carcinoma was a new addition to the list of head and neck tumors by World Health Organization in 2017. This lesion has scarcely been reported and a lack of pathognomonic markers for diagnosis exists. Objective The aim of the study was to summarize findings from the available literature to provide up-to-date information on sclerosing odontogenic carcinoma and to analyse clinical, radiological, and histopathological features to obtain information for and against as an odontogenic malignancy. Methods We conducted a comprehensive review of literature by searching Pubmed, EBSCO and Web of Science databases, according to PRISMA guidelines. All the cases reported as sclerosing odontogenic carcinoma in English were included. Data retrieved from the articles were gender, age, clinical features, site, relevant medical history, radiographical findings, histopathological findings, immunohistochemical findings, treatments provided and prognosis. Results Mean age at diagnosis of sclerosing odontogenic carcinoma was 54.4 years with a very slight female predilection. Sclerosing odontogenic carcinoma was commonly reported in the mandible as an expansile swelling which can be asymptomatic or associated with pain or paraesthesia. They appeared radiolucent with cortical resorption in radiograph evaluation. Histologically, sclerosing odontogenic carcinoma was composed of epithelioid cells in dense, fibrous, or sclerotic stroma with equivocal perineural invasion. Mild cellular atypia and inconspicuous mitotic activity were observed. There is no specific immunohistochemical marker for sclerosing odontogenic carcinoma. AE1/AE3, CK 5/6, CK 14, CK19, p63 and E-cadherin were the widely expressed markers for sclerosing odontogenic carcinoma. Surgical resection was the main treatment provided with no recurrence in most cases. No cases of metastasis were reported. Conclusion From the literature available, sclerosing odontogenic carcinoma is justifiable as a malignant tumor with no or unknown metastatic potential which can be adequately treated with surgical resection. However, there is insufficient evidence for histological grading or degree of malignancy of this tumor. Resumo Introdução O carcinoma odontogênico esclerosante é a nova adição à lista de tumores de cabeça e pescoço da Organização Mundial da Saúde em 2017. Essa lesão é pouco relatada e não há marcadores patognomônicos para o diagnóstico. Objetivo Resumir os achados da literatura disponível para fornecer informações atualizadas sobre o carcinoma odontogênico esclerosante e analisar as características clínicas, radiológicas e histopatológicas a favor e contra sua classificação como uma lesão odontogênica maligna. Método Uma revisão abrangente da literatura foi feita nos bancos de dados Pubmed, Ebsco e Web of Science, de acordo com as diretrizes do Prisma. Todos os casos relatados em inglês como carcinoma odontogênico esclerosante foram incluídos. Os dados recuperados dos artigos foram sexo, idade, características clínicas, sítio do tumor, histórico médico relevante, achados radiográficos, achados histopatológicos, achados imuno-histoquímico, tratamentos instituídos e prognóstico. Resultados A média de idade ao diagnóstico de carcinoma odontogênico esclerosante foi de 54,4 anos, com uma predileção muito leve pelo sexo feminino. Tumores do tipo carcinoma odontogênico esclerosante foram comumente relatados na mandíbula como um edema expansivo, que pode ser assintomático ou associado a dor ou parestesia. Eles têm aparência radiolucente com reabsorção cortical na radiografia. Histologicamente, o carcinoma odontogênico esclerosante é composto por células epitelioides em estroma denso, fibroso ou esclerótico com invasão perineural ambígua. Atipia celular leve e atividade mitótica imperceptível foram observadas. Não há um marcador imuno-histoquímico específico para SOC. AE1/AE3, CK 5/6, CK 14, CK19, p63 e E-caderina foram os marcadores amplamente expressos para carcinoma odontogênico esclerosante. A ressecção foi o principal tratamento feito sem recorrência na maioria dos casos. Nenhum caso de metástase foi relatado. Conclusão De acordo com a literatura disponível, é justificável classificar o carcinoma odontogênico esclerosante como um tumor maligno com nenhum ou desconhecido potencial metastático, que pode ser tratado adequadamente com ressecção cirúrgica. Entretanto, não há evidências suficientes para a graduação histológica ou de malignidade desse tumor.

Ghost cell odontogenic carcinoma (GCOC) is a rare malignant neoplasm, representing 3% of all ghost cell lesions of the jaws. They can arise de novo or from a pre-existing calcifying odontogenic cyst (COC) or dentinogenic ghost cell tumour (DGCT). A systematic review of the literature reported only 12 cases of a GCOC arising from a pre-existing COC. This report highlights an additional case of a GCOC arising from a pre-existing COC after 3 years in an adolescent male. The patient initially presented with a painless swelling of the right mandibular corpus. Panoramic radiographic examination showed an expansive unilocular radiolucent lesion. After 3 years, the radiographic features appeared more aggressive with increased expansion and cortical perforation. A wide surgical resection was performed, whereby the lesion was diagnosed as a GCOC. Due to the rarity of these malignant neoplasms, limited information is available regarding their biological behaviour. One-year follow-up revealed no clinical signs of recurrence.

Background This study aimed to search for scientific evidence concerning the accuracy of computer-assisted analysis for diagnosing odontogenic cysts. Material and Methods A systematic review was conducted according to the PRISMA statements and considering eleven databases, including the grey literature. Protocol was registered in PROSPERO (CRD 42020189349). The PECO strategy was used to define the eligibility criteria and only studies involving diagnostic accuracy were included. Their risk of bias was investigated using the Joanna Briggs Institute Critical Appraisal tool. Results Out of 437 identified citations, five papers, published between 2006 and 2019, fulfilled the criteria and were included in this systematic review. A total of 5,264 images from 508 lesions, classified as radicular cyst, odontogenic keratocyst, lateral periodontal cyst, glandular odontogenic cyst, or dentigerous cyst, were analyzed. All selected articles scored low risk of bias. In three studies, the best performances were achieved when the two subtypes of odontogenic keratocysts (solitary or syndromic) were pooled together, the case-wise analysis showing a success rate of 100% for odontogenic keratocysts and radicular cysts, in one of them. In two studies, the dentigerous cyst was associated with the majority of misclassifications, and its omission from the dataset improved significantly the classification rates. Conclusions The overall evaluation showed all studies presented high accuracy rates of computer-aided systems in classifying odontogenic cysts in digital images of histological tissue sections. However, due to the heterogeneity of the studies, a meta-analysis evaluating the outcomes of interest was not performed and a pragmatic recommendation about their use is not possible. Key words:Computer-assisted diagnosis, computer-assisted image analysis, computer-assisted image processing, odontogenic cysts, keratocysts, radicular cysts.

MRI has become an invaluable diagnostic tool in all areas of the body. However, it has not been widely used to image odontogenic tumors of the jaw. Major advantages of MRI include excellent soft tissue contrast in the absence of ionizing radiation. Furthermore, diffusion-weighted MRI and dynamic contrast-enhanced MRI can be used as functional imaging techniques for assessing tissue biology. In this review article, we present representative MR images of several types of odontogenic tumors, and discuss MR imaging characteristics useful for differential diagnosis.

Background The caveolin-1 protein (structural component of membrane caveolae) plays important roles in several biological functions, such as endocytosis, cell adhesion, and cell signaling. However, this protein has been associated with mechanisms of tumorigenesis in several neoplasms. The expression patterns and roles of caveolin-1 in the oral epithelium and in embryonic and odontogenic tumor tissues are still unclear. Material and Methods The expression of caveolin-1 was evaluated in samples of the normal gingival epithelium (n=7), human tooth germ (TG) (n=12), ameloblastoma (AM) (n=83), and ameloblastic carcinoma (AC) (n=9) by immunohistochemistry. Additionally, AM samples were analyzed by qRT-PCR and Western blot. Results Most TG (91.7%), AM (73.5%) and AC (100%) samples showed diverse patterns of immunohistochemical positivity for caveolin-1, while only one gingival sample was positive. The transcript levels of cav-1 were significantly upregulated by 14.9-fold in AM tissue (P = 0.0014) compared to those in normal gingival epithelial tissue, as shown by qRT-PCR. Presence of caveolin-1 protein was confirmed by Western blot analysis. The caveolin-1 immunoexpression patterns throughout the stages of TG show its importance during odontogenesis. Conclusions The overexpression of caveolin-1 in AM and AC compared to its expression in normal gingival epithelium (adult tissue) suggests a possible role of caveolin-1 in protumoral events, but due to the similar immunoexpression observed in AM and AC, caveolin-1 may not necessarily participate in the malignant transformation process. However, future studies are needed to clarify and confirm these hypotheses. Key words:Ameloblastoma, ameloblastic carcinoma, caveolin-1, immunohistochemistry, real-time polymerase chain reaction.

Background Concomitant cemento-osseous dysplasia (COD) and aneurysmal bone cyst (ABC) are rare in the head and neck region. In our search of the English language literature, we found only one case report describing the simultaneous occurrence of COD and ABC in the head and neck region. Here, we report a case of COD associated with ABC. Further, we performed a systematic search of the literature to identify studies on patients with COD associated with nonepithelial lined cysts of the jaws. Case presentation The patient was a 32-year-old woman who was referred from a private dental clinic because of a cystic lesion below the mandibular right first molar. She had no pain or significant systemic disease. After performing panoramic radiography and cone-beam computed tomography, the imaging diagnosis was COD with a cystic lesion, such as ABC or solitary bone cyst. Excisional biopsy was performed, which revealed concomitant COD and ABC. Conclusion This case of ABC associated with COD provides insight for the diagnostic process of radiographically mixed lesions with cystic changes.

Ameloblastomas are epithelial odontogenic tumours that, although benign, are locally invasive and may exhibit aggressive behaviour. In the tumour microenvironment, the concentration of oxygen is reduced, which leads to intratumoral hypoxia. Under hypoxia, the crosstalk between the HIF-1α, MMP-2, VEGF, and VEGFR-2 proteins has been associated with hypoxia-induced angiogenesis, leading to tumour progression and increased invasiveness. This work showcases 24 ameloblastoma cases, 10 calcifying odontogenic cysts, and 9 dental follicles, used to investigate the expression of these proteins by immunohistochemistry. The anti-HIF-1α, anti-MMP-2, anti-VEGF, and anti-VEGFR-2 primary antibodies are used in this work. The results have been expressed by the mean grey value after immunostaining in images acquired with an objective of 40×. The ameloblastoma samples showed higher immunoexpression of HIF-1α, MMP-2, VEGF, and VEGFR-2 when compared to the dental follicles and calcifying odontogenic cysts. Ameloblastomas show a higher degree of expression of proteins associated with intratumoral hypoxia and proangiogenic proteins, which indicates the possible role of these proteins in the biological behaviour of this tumour.

The aims of this study were to describe the frequency of odontogenic tumours (OT) based on the World Health Organization’s (WHO) 4th edition of Head and Neck Tumours in Turkey, to compare the results with other regions and to assess the frequency changes of OT worldwide after the new WHO classification. OT were selected from the pathology department’s files between 1971-2018. In a total of 1231 OT, 1215 (98.7%) were benign, whereas malignant OT were only 16 cases (1.3%). The three most common tumours were ameloblastoma (n = 366, 29.7%), odontoma (n = 335, 27.2% both complex and compound types), and odontogenic myxoma (n = 190, 15.4%), respectively. After the 2017 classification, the decrease of OT frequency was found among 20%-42% in the selected epidemiological series because of re-classification of some lesions. The pattern of incidence in the Turkish population is similar to that in other populations. However, there are some differences in the frequency of the tumour types. It is obvious that the relative frequency of odontogenic tumours worldwide will change based on the new classification. It should be kept in mind that this is not a real decrease of OT cases. These marked changes in the frequency and prevalence of OT is just related to reclassification of some entities.

Decompression of the odontogenic keratocyst has been a long-standing treatment modality in the armamentarium of oral-maxillofacial surgeons. Many different types of effective decompression tubes have been described in the literature. They reduce the size of the cystic lesion by decreasing the intraluminal pressure, induce histologic structural changes in the epithelial lining of the cyst, and allow for bone deposition to occur from the periphery of the cystic cavity. However, many of these have pitfalls including tube dislodgement, traumatization of the oral mucosa, and mucosal overgrowth. We describe a novel technique using an indwelling voice prosthesis (Inhealth Technologies, Carpinteria, CA) to decompress odontogenic keratocysts. We found that our method provides effective decompression using appropriate-length prostheses fit to the cyst dimensions. It provides improved comfort in patients, with less mucosal irritation or overgrowth, improved ease of irrigation, and improved retention that often does not require sutures.

Central giant cell granuloma (CGCG) can coexist with other benign lesions of the jaw. These hybrid lesions are diagnostically challenging to both oral pathologists and radiologists. This work systematically reviews the clinical and radiographic features of hybrid-CGCG lesions in the jaws.Three reviewers conducted an electronic search of five databases for histologically diagnosed hybrid-CGCG lesions in human jaws.Thirty-four of 1224 articles met the inclusion criteria. Of 39 hybrid-CGCG lesions, 14 (35.9%) were central odontogenic fibroma, 11 (28.2%) were central ossifying fibroma, seven (17.9%) were fibrous dysplasia, and seven (17.9%) were other bone conditions. There were 22 females and 17 males with a mean age of 30.5 ± 19.9 years. 89.5% of hybrid-CGCG lesions were well defined, 57.9% were non-corticated, 60.5% were radiolucent, and 66.7% were in the posterior mandible. Most hybrid lesions affected the cortical plates by thinning, expansion, or perforation (93.1%), displaced, or resorbed teeth (60%).The radiographic features of hybrid-CGCG lesions vary according to the concurrent bony lesion. Hybrid-CGCG lesions altered the radiographic appearance with the following entities: fibrous dysplasia, melorheostosis, and Paget's disease. Optimal imaging modalities are crucial to detail radiographic features and direct representative biopsy of suspicious sites that may host a CGCG hybridisation.

The calcifying odontogenic cyst is as a benign, rare developmental odontogenic cyst with a wide range of histologic characteristics. It may present along with other odontogenic pathologies such as odontoma, ameloblastoma, adenomatoid odontogenic tumor, ameloblastic fibroma, and ameloblastic fibro-odontoma. Clinically, it can be an either intra- or extraosseous painless swelling that can produce cortical expansion. It affects mostly the anterior area of the mandible. Radiographically, it appears as a well-circumscribed unilocular radiolucency containing flecks of indistinct radiopacities. In about one third of cases, an impacted tooth is associated. In this paper, we employ a patient with an enormous calcifying odontogenic cyst to review both the pathology and active decompression and distraction sugosteogenesis, a novel technique employed to treat odontogenic entities. This dual approach usually results in an accelerated bone healing (sugosteogenesis), partial removal of the cystic epithelium, thickening of the wall, and migration of chronic inflammatory cells which triggered epithelial modulation, ultimately causing a realignment in the biologic behavior of the lesion.

Cripto-1 also known as teratoma-derived growth factor 1 (TDGF-1) belongs to the EGF-CFC family of growth factor-like molecules. Cripto-1 is involved with embryonic development and not expressed in adult tissue, but some tumours are accompanied by reactivation. The aim of this study was to evaluate the immunohistochemical expression of Cripto-1 in most common odontogenic cysts and tumours. Thirty ameloblastomas, 30 keratocysts, 30 dentigerous cysts and two ameloblastic carcinomas were evaluated using the polymeric immunoperoxidase technique. Immunohistochemical expressions were analysed by the IRS (immunoreactive score). Statistical analyses were performed by the Kruskal–Wallis and Mann–Whitney tests (p ≤ 0.05). Age ranged from 9 to 75 years old, with a prevalence of females (n = 49/53.3%). The mandible was the most affected anatomical site (n = 69/75.0%). Cripto-1 immunoexpression was observed in all ameloblastoma, keratocyst and ameloblastic carcinoma cases, although nine dentigerous cyst cases (30%) were negative. Expression scores were higher in ameloblastoma, keratocyst and ameloblastic carcinoma cases (median ranging from 8 to 11) when compared with dentigerous cyst cases (median of 2), with a statistically significant difference (p

The first detailed description of calcifying epithelial odontogenic tumor (CEOT) are ascribed to Jens Pindborg, but this tumor was described some years previously. Subsequently, CEOT was included in the 1971 WHO classification of odontogenic tumors and a since then number of variants have been described, which have added confusion to the diagnostic criteria. We aimed to survey the literature on the variants of CEOT, in parallel with a review of our single institution experience of CEOTs. Cases identified were collated, including available clinical, radiological and histological information and then reviewed, taking into account changes in the understanding and classifications of odontogenic tumors since initial diagnosis. We identified 26 cases from 1975 to 2017 for which histological material was available. Of these, only 13 (50%) showed the “classic” histological appearance, whilst two cases were identified as recognized variants. In 11 cases, other diagnoses or a differential diagnosis were preferred, with no agreed diagnosis in four of these. The proliferation fraction (Ki67) in the 10 cases tested was 2.1% ± 0.18. These findings illustrate the diagnostic challenges in this group of tumors and highlight the gaps in knowledge. Techniques, such as EWSR1 gene cytogenetic analysis, may be helpful in cases with clear cells. However, in other areas of controversy, including the non-calcifying and Langerhans cell rich variants, further investigation, perhaps utilizing sequencing technologies may be needed to refine the classification. Owing to the relative rarity of these lesions it would be beneficial if future work could be pursued as an international collaboration.

Pediatric mandibular tumors present an aggressive biological behavior and difficult diagnosis. A wide range of odontogenic and nonodontogenic tumors comprise the spectrum of these lesions. We report a case of a 1-year-old male child patient showing facial asymmetry symptomatic of an expansive lesion extending throughout the body and ramus of the left hemimandible with a diameter of 8 cm. The histopathological report suggested a high-grade mucoepidermoid carcinoma (MEC), recommending further immunohistochemical investigation of the ectomesenchymal or neuroectodermal origin of the tumor cells. The patient evolved with extensive bilateral pleural effusion followed by metastasis in the middle third of the right humerus, and died 2 months after the first biopsy procedure by acute renal failure with tubular necrosis, before a final inconclusive immunohistochemical report was reached. The lack of resources for less-favored regions of Brazil impairs rapid biomolecular examinations such as immunohistochemical resulting in delay of appropriate therapeutic procedures.

The calcifying epithelial odontogenic tumor (CEOT) was first described by Pindborg as a distinct entity in 1955. Odontogenic tumors are derived from epithelial, ectomesenchymal, and/or mesenchymal elements that are or have been a part of the tooth-forming apparatus. Of all the odontogenic tumors, CEOT accounts for 1% of the cases. There is no sex predilection, with a 2:1 predilection for the mandible, mostly in the premolar/molar region. The CEOT typically presents clinically as an intraosseous, expansile, and painless mass that exhibits slow growth. It is often locally invasive. Most often, it is associated with an impacted tooth, is asymptomatic, and requires biopsy for diagnosis. Although most of these cases are primarily intraosseous, an extraosseous tumor is also known to occur, first observed by Pindborg in 1966. The lesions were surgically enucleated, and histopathological examination confirmed CEOT. The purpose of this article is to describe one additional case of both variants of CEOT.

Odontogenic myxoma is a benign tumor, mostly located in the mandible. It shows locally aggressive behavior and requires surgical removal. Common treatment options for reconstructing the bone defects are immediate or delayed autologous bone graft or free flap. In this article, the authors present the successful reconstruction with autogenous bone graft and autologous human bone marrow mesenchymal stem, followed by distraction osteogenesis, dental implant placement and prosthodontic restoration in the mandibular defect.

Calcifying epithelial odontogenic tumor is a rare benign odontogenic tumor which accounts for approximately 1% of the entire odontogenic tumor. It was firstly described by Pindborg, and thus, is also referred to as the “Pindborg tumor”. Histologically, Pindborg tumor consists of three distinct histological compo­nents: sheets of polyhedral epithelial cells, amyloid like deposits, and calcifications. This case report describes a case of Calcifying epithelial odontogenic tumor in 26 years old female patient presented with the swelling in right posterior region of mandible. Taking into account of the aggressive nature of the lesion segmental resection of the mandible followed by reconstruction was planned for treatment. This case report highlights the importance of appropriate clinical, radiographical and histological correlation for the correct diagnosis and treatment of Pindborg tumor.

Central odontogenic fibroma is a rare benign odontogenic tumor that relies on clinical–radiographic–histological correlation to reach its diagnosis, especially its rare variants. Of these rare types is the coexistence of giant cell granuloma-like lesion, with the characteristic odontogenic epithelial rests. The presented case is a 33 years old female complaining of asymptomatic mandibular bony swelling. Radiographically, the lesion is unilocular radiolucent, without root resorption. Histological examination revealed the presence of multinucleated giant cells within the diagnosed central odontogenic fibroma. Immunohistochemical staining highlighted the presence of both components.

A noninductive tumor of odontogenic epithelium occurs within the tooth bearing regions of the jaw in dogs and fits the conventional definition of ameloblastoma, which is distinct from, and less common than, canine acanthomatous ameloblastoma. In order to clarify the clinical and radiological features of this uncommon odontogenic tumor in dogs, we performed a retrospective study of 20 dogs that were diagnosed between 2007 and 2015. Follow-up information was obtained for 17 of 20 dogs. The study group of dogs showed no apparent age, breed, or gender predilection. Conventional ameloblastoma is typically slow growing, well demarcated, and locally destructive. Tumors most commonly occurred as a mass or focal bony swelling within the maxilla (13/20) or mandible (7/20). Based on cases with available diagnostic imaging, as either dental radiographs or computed tomographic images, the tumors were usually intraosseous and caused mixed lytic/proliferative bone changes. Nevertheless, conventional ameloblastomas did not aggressively infiltrate adjacent tissues and recurrence was not observed within the study group, even in patients with narrow surgical margins or treatment by cyst enucleation.

We present the frequency of cases of isolated odontogenic keratocysts submitted to microscopic examination at 10 Brazilian referral centres in Oral and Maxillofacial Pathology. In a retrospective (1953-2017) analysis, data on clinicoradiographic features and treatment of these lesions were collected and analysed descriptively. Among the 258,867 cases retrieved, 2,497 (0.96%) were isolated odontogenic keratocysts. In summary, an overview of individuals affected with isolated odontogenic keratocysts is reported herein. This lesion showed predilection for the posterior mandible of young adult men.

Although odontogenic lesions have been extensively described and studied, anomalous, challenging cases occasionally come to the attention of the pathologist. Here, we report the clinical and microscopic characteristics of an unusual cystic lesion of odontogenic origin. A 16-year-old male presented with swelling and pain to palpation of the right mandible as well as numbness of the right lower lip. Radiographically, the corresponding lesion was well-defined and radiolucent with internal radiopaque foci. It extended from the right first premolar posteriorly, approaching the angle of the mandible, and involved the mandibular first molar which was impacted and displaced. The second and third right mandibular molars were also impacted and displaced. The patient was treated by excisional biopsy under general anesthesia. The histopathologic examination revealed the presence of multicystic areas lined by a thin, non-keratinizing squamous epithelium that resembled the epithelial lining of a dentigerous cyst. In continuity with the cystic lining, areas of myxoid tissue reminiscent of dental papilla were observed. The myxoid tissue formed structures that were surfaced by an epithelium comprising a basal layer of ameloblast-like cells with reverse polarity of the nuclei. Above the basilar cells, additional layers of epithelial cells composed a structure resembling the enamel organ. Subjacent to the basilar ameloblast-like cells, a condensation of mesenchymal cells with polarized nuclei opposite to the ameloblast-like cells was present. These mesenchymal cells resembled odontoblasts. In addition, numerous mineralized structures amongst the odontogenic epithelial tissue were present. To date, the patient remains well and without evidence of recurrence after 36 months of follow-up.

Odontogenic tumors (OT) are considered rare events and their epidemiologic data are scarce and under-estimated in developing countries because there is no systematic collection of clinical features including histological analyses of the tissue samples. Furthermore, there is an underestimation of the disease relevance and affected people are often marginalized in spite of severe functional impairment of aero-digestive tract. Etiology of OT in humans is still unknown and it represents an important therapeutic and diagnostic challenge.Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus, a member of the arenavirus family of viruses. The disease is endemic in the rodent population in West-East Africa. Humans usually become infected with Lassa virus through exposure to the food or household items contaminated with urine or feces of infected rats. It is also reported person-to-person infections. About 80% of people infected by Lassa virus have no symptoms but the virus establishes a life-long persistent infection.The present commentary significance is to start, for the first time ever, a systematic collection of clinical features and tissue sample collection at the St. Mary’s Hospital in Lacor (Gulu) North Uganda where the considered pathologies have an important frequency. The systematic collection will allow to corroborate the possible association between arenaviruses infection and pathogenesis of odontogenic tumors in humans.

A clear cell variant of calcifying epithelial odontogenic tumor is a rare benign odontogenic neoplasm, accounting for 33 cases described in the literature. In this article, we report a challenging example of clear cell variant of calcifying epithelial odontogenic tumor of the posterior maxilla in a 45-year-old female patient showing locally aggressive growth and recurrence. Microscopically, islands of polyhedral cells containing abundant cytoplasm, well-developed intercellular bridges blended with clear cells were observed. The nuclei were frequently pleomorphic and permeated by hyaline calcified material. Immunohistochemistry revealed positivity for pan-cytokeratin (AE1/AE3), cytokeratins (CK-14 and CK-19), Bcl-2, p53, and p63. The Ki-67 proliferative index was ~10%. As odontogenic tumors are rare, when a significant clear cell component is observed, the differential diagnosis with other lesions of the jaws with similar morphology, including other odontogenic tumors with prominent clear cell component, clear cell odontogenic carcinomas, and metastatic tumors, is difficult.

Adenoid ameloblastoma is a rare benign odontogenic tumor that favors a slight predilection for male patients, fourth and fifth decades of life, and posterior regions of the jaws. To date, less than 40 cases have been reported in the English language literature. The radiographic aspects of adenoid ameloblastoma vary from unilocular and well-defined lesions to diffuse and multilocular lesions. Most of the lesions exhibit a radiolucent image and are usually large, with a mean size of 3.5 cm. Microscopically, pseudoductal structures composed of columnar cells in a palisaded arrangement formed from the parenchyma of the tumor were observed. We describe a case of adenoid ameloblastoma in a 54-year-old woman, who presented with no symptoms. Panoramic radiography showed a well-circumscribed, unilocular radiolucency in the left posterior maxilla. As odontogenic tumors are rare, some entities are infrequently encountered, making the diagnosis more difficult. Clinicians, oral and maxillofacial surgeons and oral pathologists should be familiar with the adenoid ameloblastoma and its differential diagnosis for accurate diagnosis and management.

Background The purpose of this experimental study was to compare the immunohistochemical expression of SOX2 and BCL-2 in Odontogenic Keratocyst (OKC) and Ameloblastoma (AB) specimens, and to identify a possible correlation in their expression. Material and Methods Immunohistochemical analysis was performed to evaluate SOX2 and BCL-2 expression in OKC (n = 20) and AB (n = 20). The immunoexpression was analyzed by a quantitative and qualitative scoring system. The comparison between the immunoexpression of SOX 2 and BCL-2 was assessed by the Mann-Whitney U-test. Spearman’s correlation coefficient evaluated the correlation between SOX2 and BCL-2 expressions. Results SOX2 and BCL-2 expression was observed in all specimens of OKC in the full thickness of the epithelium lining. SOX2 immunostaining was higher in OKC, in comparison with AB samples (P