Relative Frequency of Central Odontogenic Tumors: A Study of 1,088 Cases from Northern California and Comparison to Studies from Other Parts of the World

Targeted therapies in ameloblastomas and amelobastic carcinoma-A systematic review

Targeted therapy has the potential to be used in the neoadjuvant setting for odontogenic tumors, reducing the morbidities associated with major surgery. In this regard, the aim of this study was to summarize the current evidence on the different forms of targeted therapy, effectiveness, and drawbacks of this course of treatment. Four databases were searched electronically without regard to publication date or language. Grey literature searches and manual searches were also undertaken. Publications with sufficient clinical data on targeted therapy for odontogenic tumors were required to meet the criteria for eligibility. The analysis of the data was descriptive. A total of 15 papers comprising 17 cases (15 ameloblastomas and 2 ameloblastic carcinomas) were included. Numerous mutations were found, with BRAF V600E being most common. Dabrafenib was the most utilized drug in targeted therapy. Except for one case, the treatment reduced the size of the lesion (16/17 cases), showing promise. Most of the adverse events recorded were mild, such as skin issues, voice changes, abnormal hair texture, dry eyes, and systemic symptoms (e.g., fatigue, joint pain, and nausea). It is possible to reach the conclusion that targeted therapy for ameloblastoma and ameloblastic carcinoma may be a useful treatment strategy, based on the findings of the included studies.

Epidemiology of odontogenic tumours and selected cysts diagnosed at a single New Zealand oral pathology centre- A 15-year retrospective study

PURPOSE

This research aimed to investigate the relative frequency of odontogenic tumours (OT) and selected odontogenic cysts in a single oral pathology center in New Zealand from 2008 to 2023.

METHODS

Histopathological records from the Oral Pathology Centre, University of Otago (2008-2023) were examined to identify OT. Odontogenic keratocyst (OKC) and calcifying odontogenic cyst (COC), previously classified as OT were also included. Patient demographics, clinical details and histopathologic diagnoses were recorded. Data were analyzed using SPSS.

RESULTS

Of the 34,225 biopsies over the 15-year period, 1.8% were identified as OTs, COC and OKCs and accounted for 47%, 1.5% and 51.5% respectively. The most prevalent OT types were odontoma (43.7%), ameloblastoma (27%) and cemento-ossifying fibroma (7.5%). Malignant OT, ameloblastic carcinoma, constituted 1.4% of OT. The average age at diagnosis for OKC, COC and OT patients were 48.2 ± 20.9, 33.7 ± 23.3 and 28.9 ± 19.3 years. Overall, male and mandibular site predilections were observed. Recurrence of OKC and ameloblastoma occurred in 15.2% and 13.7% of patients. The time for recurrence for OKC and Ameloblastoma were 61.7 ± 56.5 months and 122 ± 152 months respectively.

CONCLUSION

The demographic features and range of OT, COC and OKC in New Zealand align with those of other western countries. The study also confirms need for long term follow up for patient with OKC and ameloblastoma.

Retrospective analysis of odontogenic myxoma and odontogenic myxofibroma in the oral and maxillofacial region: a fibrous tissue-related differentiation

The clinical differences between odontogenic myxoma (OM) and odontogenic myxofibroma (OMF), and the clinical significance of their classifications, remain unclear. This study reviewed the clinicopathological characteristics of patients with OM or OMF and evaluated the fibrous component of the specimens. Medical records of 21 patients with OM or OMF who underwent tumour resection were reviewed. The percentage of fibrous tissue on the representative sections was evaluated using haematoxylin and eosin- and Masson's trichrome-stained specimens. Histopathological diagnoses included 11 OMs and 10 OMFs with no tumour recurrence except for two cases in which the dredging method was applied. More cortical bone perforation was observed in OM than in OMF cases, without significant differences. Location-locularity and apparent diffusion coefficient value (ADC)-cortical bone perforation were significantly correlated in all OM and OMF cases. The percentage of fibrous tissue in specimens showed bimodal distribution bordered by 45%. There was a significant association between diagnosis based on 45% fibrous tissue criterion and the final pathological diagnosis. Our study showed a tendency for cortical bone perforation in OM compared to OMF and correlation between ADC and cortical bone perforation. According to the histopathological analyses, the fibrous component of each case was bimodal with 45%, which may be a criterion to distinguish between OM and OMF. Accumulating knowledge, such as significant differences in prognosis, may allow for minimal surgical treatment options based on the diagnosis according to this novel histopathological criterion.

Aggressive presentation of ameloblastic fibro-odontoma: a clinical-pathological enigma

Ameloblastic fibro-odontoma (AFO) is a rare, gnathic, benign, mixed odontogenic tumor that commonly presents in the first or second decade of life as a unilocular and rarely multilocular radiolucency with variable amounts of calcified material. Tumor progression is typically indolent, and generally accepted treatment is surgical enucleation and curettage. This case report describes an atypical presentation in a 14-year-old male with a multilocular, aggressive AFO requiring hemimandibulectomy with immediate osseous and dental "Jaw-in-a-Day" reconstruction. This report highlights the debate regarding whether AFO is a true neoplasm or an early-stage hamartoma in the continuum of complex odontoma formation. Regardless of the pathogenesis, maxillofacial surgeons and pathologists should be cognizant of the potential for AFO to develop locally aggressive behavior with considerable morbidity.

Molecular pathogenesis of ameloblastoma

Ameloblastoma (AM) is a benign, although aggressive, epithelial odontogenic tumour originating from tooth-forming tissues or remnants. Its aetiopathogenesis remains unclear; however, molecular analysis techniques have allowed researchers to progress in understanding its genetic basis. The high frequency of BRAF p.V600E as a main driver mutation in AM is well established; nevertheless, it is insufficient to explain its tumourigenesis. In this review, we aimed to integrate the current knowledge about the biology of AM and to describe the main genetic alterations reported, focusing on the findings of large-scale sequencing and gene expression profiling techniques. Current evidence shows that besides BRAF mutation and activation of the MAPK pathway, alterations in Hedgehog and Wnt/β-catenin pathway-related genes are also involved in AM pathogenesis. Recently, a tumour suppressor gene, KMT2D, has been reported as mutated by different research groups. The biological impact of these mutations in the pathogenesis of AM has yet to be elucidated. Further studies are needed to clarify the impact of these findings in the identification of novel biomarkers that could be useful for diagnosing, classifying, and molecular targeting this neoplasm.

The Enigma Unveiled: Expansile Compound-complex Odontoma in the Anterior Maxilla of a Teenager

Aim and objective

The objective of this case report is to offer insight into an expansive compound-complex odontoma located in the anterior maxilla of a 15-year-old male. The focus is placed on the importance of early detection and the progressive comprehension of odontomas.

Background

Odontomas are common odontogenic lesions that are frequently discovered during examinations for delayed tooth eruption. There are two distinct classifications for odontomas-compound odontomas and complex odontomas. With its own each set of characteristics. A timely diagnosis is critical for avoiding complications.

Case description

A male individual aged 15 years exhibited an expansive compound-complex odontoma located in the anterior maxilla. The clinical examination showed delayed tooth eruption and asymptomatic swelling. The radiographic images showed a radiopaque mass with tooth-like structures and radiolucent borders affecting the surrounding dentition. A surgical excision procedure was conducted, followed by a subsequent histopathological examination confirming the diagnosis of compound-complex odontoma. The patient continued orthodontic treatment after a 1-year follow-up without recurrence.

Clinical significance

This case emphasizes the importance of regular dental exams in detecting odontomas early. This observation also highlights the growing understanding of odontomas as hamartomatous odontogenic malformations and the challenges of diagnosing them clinically. Additional molecular investigations are required to facilitate the classification and elucidation of genetic factors.

How to cite this article

Alhazmi YA. The Enigma Unveiled: Expansile Compound-complex Odontoma in the Anterior Maxilla of a Teenager. Int J Clin Pediatr Dent 2024;17(1):82-85.

Clinicoradiopathologic Analysis of Odontomas: A Retrospective Study of 242 Cases

Odontomas are considered hamartomatous lesions and are one of the two most common odontogenic tumors of the jaw. Odontomas are classified as compound or complex. Recently, ameloblastic fibro-odontoma (AFO) and ameloblastic fibro-dentinoma were reclassified as developing odontomas. Though clinically odontomas are usually asymptomatic, they have adverse effects on adjacent teeth such as tooth impaction, delayed eruption, displacement of teeth, over-retention of teeth, and can give rise to odontogenic cysts within the jaw. We sought to evaluate the clinicoradiopathologic presentations of odontomas by collecting and analyzing the clinical, radiographic, and pathologic data of odontomas diagnosed in our institution from 2013 to 2022. Over this 10-year period, there were 242 patients with a histopathological and/or radiographic diagnosis of odontoma. There was no gender predilection and ages ranged from 3 to 101 years (median, 14 years). The second decade of life was the most prevalent (57.4%). There was no jaw predilection; however, the anterior jaw was the most common location. Ninety-four (38.8%) cases presented with clinical findings. The most common finding was tooth impaction (n = 83). Nine (3.7%) cases were histopathologically confirmed to be associated with other lesions such as dentigerous cysts (n = 8) and nasopalatine duct cyst (n = 1). The median age (25 years) of patients diagnosed with odontomas associated with cysts was older than patients with odontomas (14 years) without associated cysts. Compound odontomas were the most common type of odontoma compared to complex and AFOs with 71.4%, 26.6%, and 2%, respectively. The majority of compound odontomas involved the anterior jaw (69.3%) and mandible (54.9%) while the majority of complex odontomas involved the posterior jaw (59.6%) and maxilla (54.7%). The four AFOs were in the posterior jaw and 75% involved the maxilla. The median age (12 years) of patients diagnosed with AFO was the youngest compared to patients diagnosed with compound (13 years) and complex (16 years). In conclusion, we analyzed the clinical, radiographic, and pathologic features of 242 new cases of odontomas. Our study reaffirms that odontomas frequently affect the pediatric population and can disrupt their dentition. Based on the result of this study, our clinical recommendation to prevent problems to adjacent teeth from odontomas is for dentists to be apt in the diagnose of odontomas to ensure that they are surgically removed in a timely manner.

Analysis of the 100 most cited articles on ameloblastoma

OBJECTIVES

An increasing number of articles are published each year. The aim of this is to provide a list of the 100 most cited articles on the subject of ameloblastoma.

METHODS

A bibliographic search was performed on Google Scholar (GS), Microsoft Academic (MA), and Dimensions for ameloblastoma. A ranking was created in order of citation density. Graphical representations of keywords and authorship were created with VOSviewer. Statistical analysis was performed and only results with a 95% confidence interval were considered significant.

RESULTS

A helpful list of top 100 articles was developed to help professionals in a variety of ways. Some curiosities are discussed about this scientometric analysis in ameloblastoma articles.

CONCLUSIONS

A useful list of the top 100 most cited articles on ameloblastoma has been provided. Bibliometric and altmetric analysis using Google Scholar, Microsoft Academic, and Dimensions is a free and excellent tool, not only as a citation manager but also as a study reference.

Peripheral calcifying odontogenic cyst: a case report and comprehensive review of 60 years of literature

Peripheral Calcifying Odontogenic Cyst (PCOC) is the extraosseous form of calcifying odontogenic cyst that is limited to peripheral soft tissue without bony involvement. This case report presents a case of PCOC manifested as a progressive growth of gingival mass in a young male treated with excisional biopsy. Histological examination confirmed diagnosis of PCOC with presence of characteristic ghost cells and sporadic calcifications. No recurrence of the lesion and no complication were noted at three-year follow-up. Review of available literature on PCOC noted a predilection of occurrence in the mandible (61%) and in the anterior area of the jaws (58%). Mean age of patients was 41.7 ± SD25.43 (7-83) and 95% CI [33.6, 49.8] yrs. Mean size of the lesions was 1.38 ± SD1.1 (0.5-4.3) and 95% CI [0.93, 1.83] cm. Gender distribution was noted to be 51.3% male and 48.7% female.

Maxillary neoplasms in four dromedary camels

Four camels (Camelus dromedarius) presented to the Veterinary Teaching Hospital at King Faisal University with maxillary masses. On radiographs, the masses were multicystic and expanded the maxillary bone. The tumors were diagnosed by histopathologic examination as conventional ameloblastoma, two cases as intraosseous squamous cell carcinoma, and central odontogenic fibroma with ossification. To the authors' knowledge, this is the first report of ameloblastoma in a camel, the first detailed description of maxillary squamous cell carcinoma in camels, and the first report of central odontogenic fibroma in any animal species.

Clinical and radiological characteristics of odontomas: A retrospective study of 90 cases

PURPOSE

Odontomas represent a common clinical entity among odontogenic tumors, but are not well-addressed in the Vietnamese population. The present study aimed to determine the clinical and preclinical characteristics of odontomas and associated factors in the Vietnamese population.

MATERIALS AND METHODS

This retrospective study retrieved data from histopathological diagnoses from 2 central hospitals of Odonto-Stomatology in Ho Chi Minh City, Vietnam during 2004-2017. The odontomas were classified as complex (CxOD) or compound (CpOD) subtypes. The epidemiological, clinical, and radiological characteristics of the odontomas, stratified by subtype and sex, were obtained and analyzed.

RESULTS

Ninety cases, consisting of 46 CxODs and 44 CpODs, were included. The average age of patients was 32.4 (±20.2) years. The patients with CxOD were older than those with CpOD (P<0.05). Clinically, 67% of patients showed an intraoral bone expansion. Approximately 60% of patients with CxOD exhibited a painful symptom, about 3-fold more than those with CpOD (P<0.05), whereas almost all patients with CpOD exhibited perturbations of dentition, unlike those with CxOD (P<0.05). Radiologically, CxOD was characterized by a larger dimension than CpOD in both sexes (P<0.05), and CpOD induced complications in adjacent teeth more often than CxOD (P<0.05). The development of odontoma with advancing age differed significantly in odontoma subtypes related to their pathological origins, and between the sexes, resulting from different physiological states.

CONCLUSION

The findings of this study highlight the value of clinical and radiological features of odontomas and their associated factors for the early diagnosis and adequate treatment of younger patients.

Oral and maxillofacial literature from Middle East: a bibliometric analysis and list of top-100 most cited articles

OBJECTIVES

The aim of this work is to perform a bibliometric analysis on Middle Eastern oral and maxillofacial surgery through years and to compare the data with previous studies. A list of the top 100 most cited articles was generated.

METHODS

A Pubmed bibliographic search for literature journals specialized in oral and maxillofacial surgery in the Middle East was performed. A graphic representation of authorship and keywords was created with VOSviewer. Mendeley and Microsoft Excel were used for tabulation and data visualization. A list of the top 100 most cited articles was created using Web of Science. Some statistical tests were performed with a 95% confidence interval, which was considered significant.

RESULTS

A total of 6,536 articles were retrieved in fifteen selected oral and maxillofacial journals. A moderate correlation between number of publications and total population (R = 0.6052), low correlation with area (R = 0.302291), and a negligible correlation with the Human Development Index (HDI) were found (R = 0.1747). A disparity can be seen in the number of publications by country, leaded by Turkey (46.30%), Israel and Iran (13.68% each). The more common studied topic was oral surgery (25.77%), maxillofacial trauma (16.13%) and oral pathology (10.25%).

CONCLUSIONS

A useful list of the top 100 most cited articles on oral and maxillofacial surgery from Middle East has been created. Middle East publications on oral and maxillofacial surgery can be considered high quality (IF = 1.879). Some issues on performing an adequate selecting of MeSH keywords were discussed.

MR appearance of a rare ameloblastic fibroma with formation of dental hard tissues with histopathologic correlation: a case report

An ameloblastic fibroma with formation of dental hard tissues, which the classical name is ameloblastic fibro-odontoma (AFO), is a rare type of mixed odontogenic tumor. An 8-year-old boy was diagnosed with AFO, with an inhomogeneous high signal within the lesion shown by T2-weighted magnetic resonance imaging (MRI). Computed tomography (CT) imaging revealed a unilocular low CT value area of 24 × 19 × 26 mm with buccolingual bony expansion and cortical bone thinning on the left side of the mandible including the crown of the mandibular left second molar. In addition, multiple calcified bodies were detected within the lesion, one of which had a CT value of approximately 2200 HU, equivalent to that of enamel. MRI indicated the lesion to be sized 24 × 19 × 25 mm along with buccolingual bony expansion in the left side of the mandible. Additionally, the lesion showed an internal inhomogeneous high signal, while a portion had an especially high signal in T2-weighted images. That particularly high signal area coincided with the nodular growth area of mucus-rich mesenchymal components without the epithelial component in histopathology findings. The particularly high signal revealed by T2-weighted imaging could be attributed to the mucus-rich component. MRI was found useful for revealing differences in the internal histopathological properties of an AFO in our patient.

Aggressive central odontogenic fibroma in the maxilla: A case report

A central odontogenic fibroma is a rare benign tumor composed of mature fibrous connective tissue with variable amounts of odontogenic epithelium. It appears at similar rates in the maxilla and mandible. In the maxilla, it usually occurs anterior to the molars. Radiographically, central odontogenic fibroma commonly presents as a multilocular or unilocular radiolucency with a distinct border. This paper reports a case of an aggressive central odontogenic fibroma involving the right posterior maxilla of a 53-year-old man. Radiographs showed an extensive soft tissue mass involving the entire right maxilla with frank bone resorption. The patient had a history of 2 operations in the region, both more than 2 decades ago. Although it was impossible to confirm the previous diagnoses, it was presumed that this case was a recurrent lesion.

Malignant odontogenic tumors. A report of a series of 30 cases and review of the literature

Malignant odontogenic tumors are rare entities and can arise de novo or from malignant transformation of pre-existing lesions. The aim of the present study was to report 30 cases of malignant odontogenic tumors diagnosed at a single diagnostic center over a 38-year period.

MATERIALS AND METHODS

All cases of malignant odontogenic tumors diagnosed between 1980 and 2018 were retrieved from the files of the School of Dentistry, University of Buenos Aires; their frequency and clinical, radiographic, and histopathological features were analyzed. The obtained data were compared with the information reported in the literature.

RESULTS

Malignant odontogenic tumors accounted for 2 % of odontogenic tumors and 0.05 % of all oral-maxillofacial diseases. Mean age was 43 years (8 to 87 years). No differences in sex distribution were observed. The most frequent location was the mandible, mostly the posterior mandibular body and the ramus. Odontogenic carcinomas were the most frequent tumors, and primary intraosseous carcinomas were the most common in this group.

CONCLUSIONS

This is the largest case series of malignant odontogenic tumors diagnosed at a single center reported in the literature to date. Diagnosis of these tumors is challenging based on their rarity and complexity and relies on careful analysis of the histopathological, clinical, and radiographic features.

A Case of Odontogenic Myxoma of the Mandible with Expansion to the Alveolar Crest – Comparison of Imaging Findings and Pathological Findings: A Case Report

Background:

An odontogenic myxoma is an intraosseous tumor characterized by stellate and spindle-shaped cells embedded in an abundant myxoid or mucoid extracellular matrix. We herein describe an odontogenic myxoma that expanded not only to the bone marrow but also to the outside of the alveolar bone. Diagnosis of an odontogenic myxoma in a tooth-deficient region by imaging findings alone was difficult because the positional relationship between the tumor and the tooth is unknown. Furthermore, some of these odontogenic myxomas reportedly show rapid growth.

Case Report:

Here, we present the case of a patient, a 44-year-old man, who had a hard, bone-like swelling on his right mandible molar region and mild paresthesia on his right cheek. An odontogenic myxoma and ameloblastoma were suspected based on the imaging findings; however, pathological examination of the biopsy led to a diagnosis of odontogenic myxoma. Right segmental mandibulectomy was performed, and there was no recurrence observed after surgery.

Conclusion:

To improve the accuracy of imaging diagnosis, it is important to compare the imaging findings with the pathological findings of the surgical specimen. This comparison in the present case revealed differences in the magnetic resonance imaging signal intensity in regions with different types of cell components.

The Role of Immunohistochemistry for Primary Oral Diagnosis in a Brazilian Oral Pathology Service

A proper antibody panel selection is one of the most important factors to reach an adequate diagnosis in challenging cases. This retrospective study was designed to determine the contribution of immunohistochemistry (IHC) in the primary diagnosis of oral diseases in one of the main services of oral pathology in the State of São Paulo, Brazil, and to identify the most common antibodies used, and recommend diagnostic algorithms based on our experience with challenging lesions. A total of 1698 IHC stains were performed in 401 cases from a total of 28,804 cases received from public dental clinics and private dental practitioners within a period of 13 years, representing a frequency of 1.4% of IHC solicitations. Among these, 112 (28%) were mandatory to reach a final diagnosis and 255 (63.6%) were confirmative. In 34 (8.4%) cases, it was not possible to reach a conclusive/final diagnosis, even with IHC. Regarding the nature of the lesions, 210 (52.3%) were benign, 163 (40.6%) were malignant tumors, 13 (3.2%) were reactive, 10 (2.5%) were premalignant, and 5 (1.2%) were lesions of uncertain malignancy. Small amount of tissue of some incisional biopsies, overlapping features of spindle cell lesions (epithelial, neural, melanocytic, smooth muscle, endothelial, and fibroblastic/myofibroblastic cell differentiation), and overlapping features of salivary gland lesions were the most frequent challenges in which IHC stains were requested. Spindle cell lesions were the most frequent (22%) among all cases that required IHC to reach a final diagnosis. The implementation of IHC for routine practice requires a wide range of markers, proper antibody selection, and knowledge to interpret the subjectivity of staining. The inherent limitation of incisional biopsies was pointed as a reason to inconclusive diagnosis, despite a wide range of antibodies that our laboratory displays.

Frequency of Odontogenic Tumors: A Single Center Study of 1089 Cases in Japan and Literature Review

Several attempts have been made to classify odontogenic tumors; however, the need for a uniform international classification system led the World Health Organization (WHO) to present a classification of odontogenic tumors in 1971. We aimed to evaluate the number and types of odontogenic tumors examined at the Tokyo Dental College Hospital in Japan to determine the frequency and types of odontogenic tumors, based on the 2017 WHO classification system, as this information has not been reported previously in Japan. We also compared the results of our evaluation with those reported in previous studies. We conducted a clinicopathological evaluation of odontogenic tumors examined at the Tokyo Dental College Hospital between 1975 and 2020. This included an analysis of 1089 cases (malignant, n = 10, 0.9%; benign, n = 1079, 99.1%) based on the 2017 World Health Organization Classification of Head and Neck Tumors. We identified 483 (44.3%), 487 (44.7%), and 109 (10.0%) benign epithelial odontogenic, mixed odontogenic, and mesenchymal tumors, respectively. The most common tumor types were odontoma (42.5%) and ameloblastoma (41.9%). Of the 1089 cases, 585 (53.7%) and 504 (46.3%) were male and female patients, respectively. Ameloblastoma and ameloblastic fibroma occurred more commonly in male patients, whereas odontogenic fibroma and cemento-ossifying fibroma affected female patients primarily. The age at diagnosis ranged from three to 87 (mean, 29.05) years. In 319 (29.3%) patients, the age at diagnosis ranged from 10 to 19 years. Ameloblastoma and odontoma were the most common tumor types among patients in their 20s and those aged 10-19 years, respectively. In 737 (67.7%) and 726 (66.7%) patients, the tumors were located in the mandible and posterior region, respectively. Ameloblastoma was particularly prevalent in the posterior mandible. Odontogenic tumors are rare lesions and appear to show a definite geographic variation.

RAF1-MEK/ERK pathway-dependent ARL4C expression promotes ameloblastoma cell proliferation and osteoclast formation

Ameloblastoma is an odontogenic neoplasm characterized by slow intraosseous growth with progressive jaw resorption. Recent reports have revealed that ameloblastoma harbours an oncogenic BRAFV600E mutation with mitogen-activated protein kinase (MAPK) pathway activation and described cases of ameloblastoma harbouring a BRAFV600E mutation in which patients were successfully treated with a BRAF inhibitor. Therefore, the MAPK pathway may be involved in the development of ameloblastoma; however, the precise mechanism by which it induces ameloblastoma is unclear. The expression of ADP-ribosylation factor (ARF)-like 4c (ARL4C), induced by a combination of the EGF-MAPK pathway and Wnt/β-catenin signalling, has been shown to induce epithelial morphogenesis. It was also reported that the overexpression of ARL4C, due to alterations in the EGF/RAS-MAPK pathway and Wnt/β-catenin signalling, promotes tumourigenesis. However, the roles of ARL4C in ameloblastoma are unknown. We investigated the involvement of ARL4C in the development of ameloblastoma. In immunohistochemical analyses of tissue specimens obtained from 38 ameloblastoma patients, ARL4C was hardly detected in non-tumour regions but tumours frequently showed strong expression of ARL4C, along with the expression of both BRAFV600E and RAF1 (also known as C-RAF). Loss-of-function experiments using inhibitors or siRNAs revealed that ARL4C elevation depended on the RAF1-MEK/ERK pathway in ameloblastoma cells. It was also shown that the RAF1-ARL4C and BRAFV600E-MEK/ERK pathways promoted cell proliferation independently. ARL4C-depleted tumour cells (generated by knockdown or knockout) exhibited decreased proliferation and migration capabilities. Finally, when ameloblastoma cells were co-cultured with mouse bone marrow cells and primary osteoblasts, ameloblastoma cells induced osteoclast formation. ARL4C elevation in ameloblastoma further promoted its formation capabilities through the increased RANKL expression of mouse bone marrow cells and/or primary osteoblasts. These results suggest that the RAF1-MEK/ERK-ARL4C axis, which may function in cooperation with the BRAFV600E-MEK/ERK pathway, promotes ameloblastoma development. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

A Retrospective Study to Evaluate Biopsies of Oral and Maxillofacial Lesions

Background:

The clinical manifestations of these lesions comprises pain, paresthesia, swelling, drainage, tooth loss, root resorption, and facial deformity. Alteration in oral and maxillofacial (OMF) tissues of the lesions may cause esthetically and functionally unfavourable effects in patients.

Aims and Objectives:

To determine the frequency of odontogenic cysts, tumors, and other lesions.

Materials and Methods:

Patient's records of histopathological reports from the archives of the Department of Oral and Maxillofacial Pathology were obtained and reviewed over a period of 2 years, and therefore, the lesions were classified into four groups. In cases of recurrent lesions, only the primary diagnosis was considered. The research protocol was approved by the ethical committee of the institution.

Results:

About 56.4% of males had ameloblastoma, 54.9% of females had cementoma. 59.4% females had giant cell granuloma, 87.5% females had pyogenic granuloma, 77.2% females had osteoma, 65.1% of the female population were belongs to the benign fibro-osseous lesions and 50.2% of females were from fibrous dysplasia in group 3. About 58.8% females had squamous cell carcinoma in group 4.

Conclusion:

To adequately determine the prevalence and incidence rate of OMF lesions, biopsies performed by other specialists such as otolaryngologists and plastic surgeons in OMF regions should also be evaluated.

An observational retrospective study of odontogenic cyst´s and tumours over an 18-year period in a Portuguese population according to the new WHO Head and Neck Tumour classification

Background

Odontogenic cysts and tumours of the jaws represent one of the most prevalent groups of oral-maxillofacial lesions. We aimed to evaluate the clinical and pathological characteristics of a cohort of odontogenic cysts (OC) and odontogenic tumours (OT) of the jaws in a Portuguese population.

Material and Methods

This observational retrospective study analysed patients diagnosed with either an OC or OT of the jaws at a central hospital of Oporto, Portugal, between 1988 and 2006. Data collected from patients’ files included demographic, clinical, radiological and histopathological information. Recurrence was evaluated using univariate and multivariate analysis.

Results

The sample consisted of 397 patients, 231 males (58.2%) and 166 females (41.8%), with a mean-age of 36.7±17 years. Twenty-seven patients (6.8%) presented with more than one lesion providing a total of 433 lesions. There were 396 (91.5%) OC, mostly represented by radicular cysts (n=257;59.4%), dentigerous cysts (n=79;18.2%), or odontogenic keratocysts (n=50;11.5%). There were 37 (8.5%) OT, mostly represented by ameloblastomas (n=16;3.7%), and odontomas (n=9;2.1%). The most common initial clinical manifestation was swelling (n=224;51.7%). Recurrence was observed in 30 cases (6.9%), mostly in ameloblastomas (n=6;37.5%) and odontogenic keratocysts (n=12;24%). In the multivariate analysis the diagnosis classification of the lesion was the only independent and significant variable related with the recurrence (P=0.04).

Conclusions

Radicular cysts were the most commonly occurring type of OC and ameloblastomas the most commonly occurring OT. Amelobastomas and odontogenic keratocysts were the lesions with the highest rates of recurrence. This large sample provides useful information about the frequency profile and characteristics of OC and OT over a period of 18 years, allowing valuable comparison with data from other countries.

Key words:Odontogenic cysts and tumours, radicular cyst, dentigerous cyst, odontogenic keratocyst, ameloblastoma, recurrence.

Large myxomatous odontogenic tumor in the jaw: a case series

Objectives

Myxomatous odontogenic tumors (MOTs) are the third most common odontogenic tumors in the oral and maxillofacial region. Due to its slow-growing, but locally invasive nature, the tumor is usually detected by accident or only when it becomes a large mass, which causes facial deformity.

Materials and Methods

Current study reports three unusual cases of MOT including huge myxoma involve the mandible in middle-aged man, MOT with ossifying fibroma pattern in mandible, and MOT in maxilla of young female patient. The diagnosis and treatment strategy of MOTs was also summarized and updated.

Results

In reported three cases of patients with large MOTs, surgical treatment was indicated with fibular free flap reconstruction in the mandible and plate reconstruction in the maxilla. The tumors were successfully treated with radical resection and did not show signs of recurrence during the follow-up period.

Conclusion

Surgical treatment indication depends on size, the position of the lesion, patient systemic condition and surgeon individual experience. In the case of a large tumor, radical resection and reconstruction is the standard surgical strategy. The conservative surgical treatment including enucleation with wide curettage is still under controversy. The recurrence rate for MOTs is significantly high, up to 30%, therefore long-term follow-up is essential.

Impacted Mandibular Premolar Concomitant with Compound&ndash;Complex Odontome in a 13-year-old Girl: A Case Report

Odontomas, the benign odontogenic tumors of epithelial and mesenchymal origin, are very common in occurrence and are now widely accepted as hamartomas. Odontomes are invariably composed of enamel and dentin, and may also have variable amounts of cementum and pulp. Largely, odontomas have been categorized into the compound and complex varieties. Compound odontoma epitomizes itself as aberrations with the presence of all types of dental tissues and showing an orderly distribution in the form of tooth-like structures; whereas complex odontoma describes itself as aberrations in which the presence of some or all dental tissues and in a disorganized distribution. Herein, a case of compound–complex odontome associated with the impaction of a mandibular second premolar is being presented in a 13-year-old girl.

Impact of changing classification systems on prevalence and frequency distribution of odontogenic tumors in tertiary care center of Nagpur

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.

The use of Three-Dimensional Printed Technology for Mandibular Reconstruction in a Rare Case of Giant Odontogenic Myxofibroma

ABSTRACT

Odontogenic myxofibroma is a benign odontogenic tumor of mesenchymal tissue that generally originates from the mandible. It is an extremely rare tumor accounting for approximately 2% of all odontogenic tumors. In this report, the authors presented a giant right mandibular mass that extends to the angle of the mandible and displacing the tongue laterally caused significant malocclusion, pain, and impaired oral intake. The tumoral involvement of the mandibula required a partial mandibulectomy with the resection of right mandibular ramus, body, and bilateral parasymphysis. Right mandibular condyle was preserved. The mandibular defect was reconstructed with a fibula free flap. Three-dimensional printed maxillofacial bone model of the patient was used as contour modeling and guide. Histopathologic examination confirmed the diagnosis as odontogenic myxofibroma.The purpose of the report is to present a very rare case of odontogenic myxofibroma and its general characteristics, radiological features, differential diagnosis, surgical management, and the use of three-dimensional printing technology in the field of mandibular reconstruction.

Clinicopathological Profile of 80 Cases of Unicystic Ameloblastoma Aided by a Histopathological Comparison Using Modified Philipsen-Reichart Classification and Marx-Stern Classification

Unicystic ameloblastoma (UA) is an uncommon variant of ameloblastoma and behaves totally different from the solid multicystic variant of ameloblastoma (SMA); furthermore the histological subgroups of UA also show varied behavior regarding proliferation. The present multi-centric study was designed to present the clinicopathological features of unicystic ameloblastoma (UA) and to compare the two popular histological classifications systems. 80 satisfactory cases of UA were retrieved and evaluated for clinicopathological parameters from four teaching dental schools of North India. The cases were classified using modified Reichart and Philipsen system and Marx and Stern system followed by comparison of inter-observer variability. The results were analyzed using SPSS software. The mean age of occurrence was 30.79 ± 16.49 years. Males outnumbered females (M:F::1.67:1). The majority of cases occurred in the third decade irrespective of the gender. Most cases were found in body-angle-ramus region of the mandible. The modified Reichart and Philipsen classification yielded better interobserver agreement (kappa value 0.845). The modified Reichart and Philipsen classification yields better inter-rater agreement and is easy to reproduce amongst oral pathologists. Being simpler it may easily be understood by the operating surgeon for better treatment outcome.

Calcifying odontogenic cysts: A 20-year retrospective clinical and radiological review

OBJECTIVE

Calcifying odontogenic cysts (COCs) exhibit diverse clinical behaviours and may be associated with other benign odontogenic tumours. In this study, the clinical and radiological features of COCs were analysed according to subtypes based on the classification by Praetorius et al. Emphasis was placed on cases exhibiting atypical or aggressive radiological appearances. This information may assist the clinician to better understand the radiological spectrum of COCs.

METHODS

Histologically confirmed cases of COCs were retrospectively reviewed in a 20-year period from three tertiary institutions. The following clinical information was reviewed: patient demographics, main complaint, clinical duration, anatomical site and detailed radiological features.

RESULTS

Twenty-seven cases of COCs were included in the study. Asymptomatic swelling was the main clinical presentation with infrequent reports of associated pain. COCs had an anterior mandibular predilection. Well-demarcated borders were seen in all cases with isolated cases showing focal areas with loss of demarcation. Unilocular lesions were more common than multilocular variants. Internal calcifications were frequent and six cases presented with associated odontomas. Maxillary COCs resulted in the displacement of the maxillary sinus and/or nasal cavity walls. Radiological signs of aggression, including cortical destruction, were noted in a few cases.

CONCLUSION

Given the fact that COCs can present with a spectrum of clinical behaviours and radiological presentations, the academic debate regarding the cystic versus neoplastic nature of the entity is justifiable. The cases in the current sample presented with diverse presentations, ranging from indolent to lesions with significant growth and aggression.

Central Odontogenic Fibroma: characteristics and management

Introduction: Central Odontogenic Fibroma (COF) is a rare benign odontogenic tumour of the jaws. Until its recent change in classification by the WHO in 2017, this entity has gone without an agreed upon definition for many years. For this reason, COF would remain largely unknown to practitioners. Corpus: The pedagogical objectives of this article are, through a systematic review of the literature using the PRISMA methodology, to list the epidemiological, aetiological, clinical, radiological, histological, therapeutic and prognostic characteristics of COF. All the data collected made it possible to establish a COF management summary for practitioners in order to optimize it. Conclusion: Based on the 135 cases listed, it appears that surgical enucleation is the treatment of choice for COF. The recurrence rate is low and malignant transformation has never been reported. However, regular clinical and radiological follow-up of patients over several years seems to be a justified precaution.

Ghost cell odontogenic carcinoma arising in the background of a calcifying odontogenic cyst

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.

World Health Organization Classification of Odontogenic Tumors and Imaging Approach of Jaw Lesions

Tumors of the jaws represent a heterogeneous group of lesions that are classified histologically in the World Health Organization Classification of Odontogenic Tumors (2017). This article provides an update of the current nomenclature. The main role of imaging is to describe the precise location and extent of these lesions. Although characterization of imaging is often difficult due to overlapping characteristics, imaging is helpful to define which lesions should be referred for histologic examination and subsequent treatment planning. Location and density are the cardinal criteria for potential characterization on imaging. Radiologically, lesions may be radiolucent, radiopaque, or of mixed density. Additional criteria include lesion demarcation, morphology, cortical breakthrough, periosteal reaction, and adjacent soft tissue changes. Final lesion characterization is only definitive after interdisciplinary discussion and radiopathologic correlation. Correct diagnosis is obtained by a combination of the patient's age, lesion location, and clinical and radiologic presentation. It is important that all physicians use a uniform nomenclature.

Central Odontogenic Fibroma with the Presence of Large Fibroblasts of Varying Morphology

A patient with an odontogenic fibroma (OF) with the presence of fibroblasts of varying morphology is presented, and the main microscopic differential diagnosis is discussed. Case report: a 51-year-old man complained of a swelling in the anterior region of the mandible. The panoramic radiograph showed a radiolucent, well-defined multilocular image, with displacement of the roots of the left mandibular incisors and canine. A cone beam computed tomography examination revealed a hypodense image, with delicate bone spicules inside, divergence of the tooth roots and destruction of the buccal cortical bone. Under the differential diagnosis of a desmoplastic ameloblastoma or a squamous odontogenic tumor, an incisional biopsy was made. Microscopically, deeply collagenized tissue with scarce odontogenic epithelium islands, large fibroblasts of varying morphology and calcified material was observed. A diagnosis of OF was made. Surgical removal was carried out, and the specimen was examined. Identical aspects were found, and the immunohistochemical reaction for pan-cytokeratin was carried out to identify the odontogenic epithelial cells. The definitive diagnosis of OF was confirmed, and we emphasize the importance of the correlation of all characteristics for a definitive diagnosis.

Amyloid Variant of Central Odontogenic Fibroma in the Mandible: A Case Report and Literature Review

Patient: Male, 35-year-old

Final Diagnosis: Central odontogenic fibroma

Symptoms: Asymptomatic

Medication:—

Clinical Procedure: Enucleation • surgery removal

Specialty: Dentistry

Odontogenic Myxoma: A 23-Year Retrospective Series of 38 Cases

Odontogenic myxoma (OM) is an uncommon benign odontogenic tumor arising in the jaw. Though it has slight histologic overlap with other entities, definitive diagnosis is imperative considering the tumor's aggressive nature, high recurrence rate, and necessity of radical surgical intervention in large-sized lesions. With IRB approval, a retrospective search of the University of Florida College of Dentistry Oral Pathology Biopsy Service archives from 1994 to 2017 for diagnosis of OM of the jaw was performed. Biopsy reports and original slides for each case were assessed and reviewed along with any accompanying radiographs to confirm the diagnosis. Immunohistochemical staining was utilized to exclude entities with histologic overlaps, such as intraosseous myxoid neurofibroma. A total of 38 cases were included. The patients' age ranged from 6 to 84 years, with a mean age of 37.47 years. Females comprised two-thirds of the cases (n = 25) versus males (n = 13). The mandible was the most affected at 60.5% (n = 23), followed by maxilla 39.4% (n = 15). Posterior jaw involvement was higher than anterior in both the mandible (n = 20 versus n = 3) and the maxilla (n = 11 versus n = 4). Most lesions presented clinically as expansile masses with variable radiographic appearance. The clinical impression from submitting providers included "gelatinous masses", abscesses, odontogenic lesions, fibro-osseous lesions, soft tissue or bone neoplasms, and reactive gingival lesions. A consensus of odontogenic myxoma as a diagnosis was rendered for 30 cases (79%), while in 8 cases (21%) that exhibited a more fibrous stroma was identified as fibromyxoma. OM may exhibit a varied demographic and clinical profile with a wide spectrum of histologic presentations. Pathologists should be sentient of this variability in order to arrive at an accurate diagnosis and correctly manage these patients.

Odontogenic tumors: A review of 93 cases in the Vidharba region of Maharashtra

Background:

Tumors of the odontogenic origin (OTs) are rare tumors accounting for 1% of all the jaw tumors in the oral cavity. The behavior of these tumors ranges from hamartomatous proliferation to malignant neoplasm.

Aim:

The aim of this study was to determine the epidemiological data, clinical and histopathological picture with variants of the OTs diagnosed at our institute in the Vidarbha region.

Settings and Design:

A retrospective study was carried out with the permission from the institutional authorities. The archival records of the Department of Oral Pathology and Microbiology were reviewed.

Materials and Methods:

A total of 93 cases of OTs were reviewed retrospectively from the archival records of the Department of Oral Pathology and Microbiology from January 2008 to December 2018. Statistical analysis was carried out and the determination of the age, gender, jaw, site, diagnosis, variants and year-wise distribution of odontogenic lesions was taken out using the SPSS software.

Results:

Ninety-three cases of OTs were identified. The most common OT identified was ameloblastoma (n = 37/39.7%) followed by keratocystic OT (n = 8/8.6%), adenomatoid OT (n = 7/7.5%) and odontome (O) (n = 6/6.4%). The tumors were diagnosed in a wide age range from 1^st to 3^rd decennium of life. The mandibular posterior region was the most commonly affected anatomical site with the maxilla and mandible ratio of 1:6.

Conclusion:

OTs were found to be rare in the sample studied. The findings of the study were in concordance to those of Asian and African series. Variations were shown from the series of American reports, and further investigations are needed for this disparity.

Odontogenic Myxoma: Systematic review and bias analysis

BACKGROUND

Odontogenic myxoma (OM) is a rare neoplasm, which originates from odontogenic ectomesenchyme. There is no study in the literature that analyses the best standards for OM diagnosis and how the treatment modalities may influence the recurrence rates.

OBJECTIVE

To evaluate the best standards for odontogenic myxoma (OM) diagnosis and treatment, and how these may influence the recurrence rates.

STUDY DESIGN

Two independent researchers performed a systematic review in many databases. Fifty-two eligible studies were included for qualitative analysis. Bias analysis was conducted according to Oxford Centre for Evidence-Based Medicine.

RESULTS

A total of 1363 OM cases were reported on, and female gender with average age of 27 years is the most common patient profile. Conventional microscopic findings were observed in 93.43% of the reported cases. In 57.49% of the cases, multilocular radiographic appearance was present, followed by unilocular appearance (32.87%). Posterior mandible was the site with the major prevalence, while surgical resection was the most common treatment modality, followed by enucleation. Recurrence rates for both treatment modalities were approximately close (13.04% and 25.0%, respectively).

CONCLUSION

The correct diagnosis of OM relies on the association of clinical, radiographic and microscopic findings. About imaging examinations, panoramic radiography and computed tomography are sufficient for the evaluation of OM. Recurrence rates were closely among the two most used surgery treatments. So according to some clinical-radiological aspects, conservative surgery may be preferred than aggressive surgery modalities.

Differential expression of nicotinamide N-methyltransferase in primary and recurrent ameloblastomas and odontogenic keratocysts

BACKGROUND

Odontogenic tumours are a group of rare heterogeneous diseases that range from hamartomatous tissue proliferations to benign and malignant neoplasms. Recurrences can occur after 10 years, so long-term clinical and radiological follow-up is required. The study of the molecular mechanisms involved in the development of these lesions is necessary to identify new prognostic markers. In this study, we evaluate the possible role of nicotinamide N-methyltransferase (NNMT) in ameloblastomas (AM) and odontogenic keratocysts (OKC).

MATERIALS AND METHODS

A total of 105 surgical specimens of primary and recurrent lesions were obtained from 55 patients (25 AM, 30 OKC). In particular, 50 AMs (25 primary, 25 recurrences) and 55 OKCs (30 primary, 25 recurrences) were retrieved. We carried out immunohistochemical analyses to evaluate the cytoplasmic expression of NNMT, measuring the percentage of positive cells and the value of NNMT expression intensity.

RESULTS

NNMT expression was significantly higher in recurrent than primary AMs (P = .0430). This result was confirmed by staining intensity, showing more cases with moderate/intense staining in recurrent AMs (P = .0470). NNMT expression was significantly lower in recurrent than primary OKC (P = .0014). Staining intensity showed more cases with moderate/intense staining in primary OKCs (P = .0276).

CONCLUSIONS

This report is the first to evaluate NNMT expression in odontogenic lesions and to demonstrate a differential expression in recurrent AMs and OKCs, suggesting that there is potential for use of NNMT as prognostic marker.

Ameloblastoma with mucous cells: A clinicopathological, BRAF mutation, and MAML2 rearrangement study

OBJECTIVES

To investigate the clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement of ameloblastoma with mucous cell differentiation.

MATERIALS AND METHODS

Five cases of ameloblastoma with mucous cell differentiation were retrospectively studied. Clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement were analyzed. Follow-up information was available for all cases.

RESULTS

Of five cases, two cases were male and three were female, aged 18-55 years. Four cases were located in the mandible and one case in the maxilla. Histologically, four of the five cases (80%) presented with cystic features and three of the five cases (60%) with varying degrees of squamous metaplasia. The mucous cells were located in the epithelial islands or the luminal aspect of the cystic cavities. The BRAF V600E mutation was found in three of five cases (60%). All the cases showed no MAML2 rearrangement. Two cases were recurrent lesions, and one case had a local recurrence during the follow-up.

CONCLUSIONS

Ameloblastoma with mucous cell differentiation is closely related to the cystic features, squamous metaplasia, and shows a high prevalence of BRAF V600E mutation. The absence of MAML2 rearrangement reveals that ameloblastoma with mucous cell differentiation and central mucoepidermoid carcinoma (MEC) are two distinct tumor entities.

Differential Diagnosis of Periapical Radiopacities and Radiolucencies

Periapical pathoses represent changes noted at the apices of teeth within the alveolar process that are suspected on examination, visualized via imaging, and confirmed via histopathology. They can be bone forming or destructive. There are pathologic entities that show both types of changes at the apical regions. These lesions must be identified if they are odontogenic in origin because treatment modalities differ. This article discusses identification of radiopaque and radiolucent lesions noted on radiographs. The common opacities and lucencies are described. When required, advanced imaging is used to depict changes within the bone near the periapical regions of mandibular and maxillary teeth.

Evaluation of biopsies of oral and maxillofacial lesions: a retrospective study

Objectives

This study aimed to determine the prevalence of odontogenic cysts, tumors, and other lesions among reports in the archives of the Department of Oral and Maxillofacial Surgery at the Faculty of Dentistry affiliated with Kocaeli University collected over a four-year period.

Materials and Methods

In this retrospective study, patient records from the archive of the Department of Oral and Maxillofacial Surgery from 2014 to 2018 were reviewed. Patient demographic information (age and sex) and lesion location were recorded and analyzed.

Results

From a total of 475 files reviewed, odontogenic cyst was confirmed in 340 cases (71.6%), and odontogenic tumor was confirmed in 52 cases (10.9%). Regarding odontogenic cyst type, the most common was radicular cyst (216 cases), followed by dentigerous cyst (77 cases) and odontogenic keratocyst (23 cases). Among odontogenic tumors, the most frequent was odontoma (19 cases), followed by ossifying fibroma (18 cases) and ameloblastoma (9 cases). Giant cell granuloma was also reported in 35 cases.

Conclusion

The distribution pattern of odontogenic cysts and tumors in our retrospective study is relatively similar to that reported in the literature. Complete clinical reports for final diagnosis of these lesions and routine follow-up examinations are very important for treatment.

"Two third tumor": A case report and its differential diagnosis

Adenamatoid odontogenic tumor (AOT) is an odontogenic tumor with a prevalence of 2.2–7.1%. AOT is a benign, noninvasive, and progressive lesion which is also known as “a two third tumor.” As the name suggests the tumor occurs in the maxilla in two third of cases. It occurs in young patients in two third of cases and associated with missing or unerupted teeth in two third of cases. Two third cases are associated with the maxillary canine. Characterized by slow growing, gradually enlarging, painless swelling associated with missing teeth. We report a case of a male patient of age 22 years, with characteristic findings. AOT resembles different odontogenic cysts and tumors which may include dentigerous cyst, globulomaxillary cyst, ameloblastoma, and other entities, hence must be well differentiated. Conservative surgical enucleation is the treatment of choice. Recurrence rate for AOT is 0.2%. Prognosis is excellent when completely removed in toto.

A multi-centre evaluation of malignant odontogenic tumours in Nigeria

Introduction

odontogenic tumors originate from neoplastic transformation of the remnants of tooth forming apparatus. There are varying degrees of inductive interactions between odontogenic ectomesenchyme and epithelium during odontogenesis, leading to lesions that vary from benign to malignant. Malignant odontogenic tumours (MOTs) are very rare and are classified according to embryonic tissue of origin. Recently, there has been a few changes to the classification of MOTs according to the World Health Organization's (WHO) classification in 2017. This study aims to evaluate and reclassify MOTs, using a multi-centre approach in some major tertiary dental hospitals in Nigeria.

Methods

this study reviewed the clinicopathological data on 63 cases of MOT diagnosed over 25 years in five major tertiary dental hospitals in Nigeria. All MOT cases were reclassified according to the recent revision to the 2017 WHO classification of odontogenic tumours.

Results

from a total of 10,446 biopsies of oral and jaw lesions seen at the 5 study centres over the 25-year study period, 2199 (21.05%) cases were found to be odontogenic tumours (OTs), of which 63 were MOT. MOTs constituted 0.60% of the total biopsy cases and 2.86% of OTs. Odontogenic carcinomas presented with a mean age higher than odontogenic sarcomas. According to our 2017 WHO reclassification of MOTs, odontogenic carcinomas, ameloblastic carcinomas and primary intraosseous carcinomas were found to be the top three lesions, respectively. Carcinosarcomas were found to be extremely rare.

Conclusion

using a multi-centre approach is a robust way to reduce diagnostic challenges associated with rare maxillofacial lesions such as MOTs.