Oral manifestations of amyloidosis and the diagnostic applicability of oral tissue biopsy.

BACKGROUND: Amyloidosis exhibits a variable spectrum of systemic signs and oral manifestations that can be difficult to diagnose. This study aimed to characterize the clinical, demographic, and microscopic features of amyloidosis in the oral cavity. METHODS: This collaborative study involved three Brazilian oral pathology centers and described cases with a confirmed diagnosis of amyloidosis on available oral tissue biopsies. Clinical data were obtained from medical records. H&E, Congo-red, and immunohistochemically stained slides were analyzed. RESULTS: Twenty-six oral biopsies from 23 individuals (65.2% males; mean age: 59.6 years) were included. Oral involvement was the first sign of the disease in 67.0% of cases. Two patients had no clinical manifestation in the oral mucosa, although the histological analysis confirmed amyloid deposition. Amyloid deposits were distributed in perivascular (88.0%), periacinar and periductal (80.0%), perineurial (80.0%), endoneurial (33.3%), perimuscular (88.2%), intramuscular (94.1%), and subepithelial (35.3%) sites as well as around fat cells (100.0%). Mild/moderate inflammation was found in 65.4% of cases and 23.1% had giant cells. CONCLUSIONS: Amyloid deposits were consistently found in oral tissues, exhibiting distinct deposition patterns. Oral biopsy is less invasive than internal organ biopsy and enables the reliable identification of amyloid deposits even in the absence of oral manifestations. These findings corroborate the relevance of oral biopsy for the diagnosis of amyloidosis.

ChatGPT and dentistry: a step toward the future.

This article aims to explore the integration of ChatGPT, an advanced conversational artificial intelligence model, in the field of dentistry. The review primarily consists of information related to the capabilities and functionalities of ChatGPT and how these abilities can aid dental professionals. This study includes data from research papers, case studies, and relevant literature on language models, as well as papers on dentistry, patient communication, dental education, and clinical decision-making. A systematic approach was used to select relevant studies and literature. The selection criteria focused on papers that specifically discussed the integration of language models, ChatGPT in particular, in dentistry and their applications. The study findings revealed that ChatGPT has significant potential to revolutionize dentistry by offering various applications and benefits. It can enhance patient engagement and understanding through personalized oral health information and guidance. In dental education, ChatGPT can provide interactive learning, case studies, and virtual patient simulations. ChatGPT can also assist researchers in analyzing dental literature, identifying patterns, and generating insights. Moreover, it supports dentists with evidence-based recommendations, treatment options, and diagnostic support. Integrating ChatGPT in dentistry can be highly beneficial, but it is crucial to address ethical considerations, accuracy, and privacy concerns. Responsible implementation and continuous improvement of its functionalities are necessary to ensure that patient care and outcomes are improved.

Radiological aspects of lymphomas and leukaemias affecting the jaws: A systematic review.

BACKGROUND: This systematic review aimed to investigate the radiological features of lymphomas and leukaemias affecting the jaws. METHODS: A systematic literature review was conducted using the electronic databases of PubMed, Web of Science and Scopus. Articles that contained sufficient radiographic examinations (periapical, panoramic or computed tomography images) for individual cases were included. Additionally, either immunohistochemical or molecular confirmation was required prior to inclusion. Three authors evaluated and described the image quality and radiological features. RESULTS: From an initial 1079 articles screened, 129 cases were included, containing 88 tomographic, 76 panoramic and 26 periapical examinations. The quality of the majority of images was sufficient for evaluation. Diffuse large B-cell lymphoma, Burkitt lymphoma, leukemic infiltration, plasmablastic lymphoma and extranodal Natural killer (NK)/T-cell lymphoma, nasal type were the most common subtypes. Involved teeth presented with mobility in 37.2% of the cases and a provisional diagnosis of inflammatory/infectious dental disease was considered in 49.2% of cases. Computed tomography exams were available for 76% of the cases, with most presented with an osteolytic lesion with ill-defined borders. Periosteal reactions were uncommon. CONCLUSION: Lymphoma/leukaemia infiltrates of the jaw bones are usually of high-grade subtypes and rarely present with periosteal reactions.

Symptomatic subgemmal neurogenous plaque in patients with COVID-19: Is there an association?

BACKGROUND: Subgemmal neurogenous plaques (SNP) are composed of neural structures found in the posterolateral portion of the tongue, rarely biopsied as most of them are asymptomatic or eventually only clinically managed. We aimed to investigate a case series of possible correlation of symptomatic subgemmal neurogenous plaque (SNP) with coronavirus disease 2019 (COVID-19). METHODS: Eleven formalin-fixed paraffin-embedded cases from patients with previous confirmed COVID-19 (by RT-PCR) were retrieved from two pathology files. Histological sections were morphologically studied, and then submitted to immunohistochemical reactions against S-100 and neurofilament proteins, neuron-specific enolase, Glial fibrillary acidic protein (GFAP), synaptophysin, CD56, Ki67, cytokeratins (7, 8-18, 19, 20), nucleocapsid and spike proteins (SARS-CoV-1; and -2) and epithelial membrane antigen (EMA) antibodies. Clinical data were retrieved from the patients' medical files, including the symptoms and the complete history of the progression of the disease. RESULTS: The patients who had COVID-19 included in this study experienced painful lesions in the tongue that corresponded to prominent or altered SNP. Microscopically, neural structures were positive for S-100, GFAP and neurofilament protein. And the cellular proliferative index (by Ki-67) was very low. CONCLUSION: Thus, based on the current results, we hypothesize that symptomatic SNP may be a late manifestation of COVID-19 infection.

Deep learning applied to the histopathological diagnosis of ameloblastomas and ameloblastic carcinomas.

BACKGROUND: Odontogenic tumors (OT) are composed of heterogeneous lesions, which can be benign or malignant, with different behavior and histology. Within this classification, ameloblastoma and ameloblastic carcinoma (AC) represent a diagnostic challenge in daily histopathological practice due to their similar characteristics and the limitations that incisional biopsies represent. From these premises, we wanted to test the usefulness of models based on artificial intelligence (AI) in the field of oral and maxillofacial pathology for differential diagnosis. The main advantages of integrating Machine Learning (ML) with microscopic and radiographic imaging is the ability to significantly reduce intra-and inter observer variability and improve diagnostic objectivity and reproducibility. METHODS: Thirty Digitized slides were collected from different diagnostic centers of oral pathology in Brazil. After performing manual annotation in the region of interest, the images were segmented and fragmented into small patches. In the supervised learning methodology for image classification, three models (ResNet50, DenseNet, and VGG16) were focus of investigation to provide the probability of an image being classified as class0 (i.e., ameloblastoma) or class1 (i.e., Ameloblastic carcinoma). RESULTS: The training and validation metrics did not show convergence, characterizing overfitting. However, the test results were satisfactory, with an average for ResNet50 of 0.75, 0.71, 0.84, 0.65, and 0.77 for accuracy, precision, sensitivity, specificity, and F1-score, respectively. CONCLUSIONS: The models demonstrated a strong potential of learning, but lack of generalization ability. The models learn fast, reaching a training accuracy of 98%. The evaluation process showed instability in validation; however, acceptable performance in the testing process, which may be due to the small data set. This first investigation opens an opportunity for expanding collaboration to incorporate more complementary data; as well as, developing and evaluating new alternative models.

The use of deep learning state-of-the-art architectures for oral epithelial dysplasia grading: A comparative appraisal.

BACKGROUND: Dysplasia grading systems for oral epithelial dysplasia are a source of disagreement among pathologists. Therefore, machine learning approaches are being developed to mitigate this issue. METHODS: This cross-sectional study included a cohort of 82 patients with oral potentially malignant disorders and correspondent 98 hematoxylin and eosin-stained whole slide images with biopsied-proven dysplasia. All whole-slide images were manually annotated based on the binary system for oral epithelial dysplasia. The annotated regions of interest were segmented and fragmented into small patches and non-randomly sampled into training/validation and test subsets. The training/validation data were color augmented, resulting in a total of 81,786 patches for training. The held-out independent test set enrolled a total of 4,486 patches. Seven state-of-the-art convolutional neural networks were trained, validated, and tested with the same dataset. RESULTS: The models presented a high learning rate, yet very low generalization potential. At the model development, VGG16 performed the best, but with massive overfitting. In the test set, VGG16 presented the best accuracy, sensitivity, specificity, and area under the curve (62%, 62%, 66%, and 65%, respectively), associated with the higher loss among all Convolutional Neural Networks (CNNs) tested. EfficientB0 has comparable metrics and the lowest loss among all convolutional neural networks, being a great candidate for further studies. CONCLUSION: The models were not able to generalize enough to be applied in real-life datasets due to an overlapping of features between the two classes (i.e., high risk and low risk of malignization).

Can SARS-CoV-2 screening in oral biopsies aid epidemiological surveillance?

BACKGROUND: Three years after the first confirmed COVID-19 case in Brazil, the outcomes of Federal government omissions in managing the crisis and anti-science stance heading into the pandemic have become even more evident. With over 36 million confirmed cases and nearly 700 000 deaths up to January 2023, the country is one of the hardest-hit places in the world. The lack of mass-testing programs was a critical broken pillar responsible for the quick and uncontrolled SARS-CoV-2 spread throughout the Brazilian population. Faced with this situation, we aimed to perform the routine SARS-CoV-2 screening through RT-qPCR of oral biopsies samples to aid in the asymptomatic epidemiological surveillance during the principal outbreak periods. METHODS: We analyzed 649 formalin-fixed paraffin-embedded oral tissue samples from five important oral and maxillofacial pathology laboratories from the north, northeast, and southeast geographic regions of Brazil. We also sequenced the whole viral genome of positive cases to investigate SARS-CoV-2 variants. RESULTS: The virus was detected in 9/649 analyzed samples, of which three harbored the Variant of Concern Alpha (B.1.1.7). CONCLUSION: Although our approach did not value aiding asymptomatic epidemiological surveillance, we could successfully identify a using FFPE tissue samples. Therefore, we suggest using FFPE tissue samples from patients who have confirmed diagnosis of SARS-CoV-2 infection for phylogenetic reconstruction and contraindicate the routine laboratory screening of these samples as a tool for asymptomatic epidemiological surveillance.

Comparison of survival outcomes between ameloblastic carcinoma and metastasizing ameloblastoma: A systematic review.

PURPOSE: To investigate and compare the demographic data, occurrence of recurrence and metastasis, and survival prognosis between ameloblastic carcinoma (AC) and metastasizing ameloblastoma (MA), based on appropriate and currently accepted eligible diagnostic criteria, in a systematic review of the literature. METHODS: An electronic search was undertaken, last updated in December 2021. Eligibility criteria included publications having enough clinicopathological information to confirm the diagnosis of these tumors. RESULTS: Seventy-seven publications reporting 85 ACs and 43 MAs were included. Both tumors were more frequent in mandible and showed different clinical profiles regarding patients' sex and age. There was no difference in the estimated cumulative survival between patients diagnosed with these tumors. Metastases mainly affected the lungs, followed by cervical lymph nodes. The mean time between the first metastasis and the last follow-up was higher for MA (p = 0.021). In addition, MA patients remained alive longer than AC patients after the first metastasis diagnosis (p = 0.041). Considering only the cases that metastasized, a higher ratio of AC patients died in comparison to MA patients (p = 0.003). The occurrence of recurrence was associated with a conservative primary treatment with both AC (p < 0.001) and MA tumors (p = 0.017). Multiple recurrent events were associated with conservative primary therapies with MA (p < 0.001) but not with AC (p = 0.121). CONCLUSION: In addition to some demographic differences, ACs that metastasize present a worse prognosis than MA. As conservative procedures are associated with multiple recurrent events, this treatment modality should be avoided for both tumors.

Oral and maxillofacial manifestations of IgG4-related disease: A clinicopathological study.

BACKGROUND: IgG4-related disease is a fibroinflammatory and immune-mediated condition, which has extremely variable clinical manifestations. In this study, we aim to investigate the clinicopathological features of IgG4-related disease involving the oral and maxillofacial region. METHODS: Cases of IgG4-related disease manifesting in the oral and maxillofacial region were retrieved from three Brazilian institutions. Clinical and serological data were obtained from the patients' medical charts, while microscopic and immunohistochemical findings were revised by oral pathologists. Diagnosis followed the American College of Rheumatology/European League against Rheumatism criteria. RESULTS: Seven patients diagnosed with IgG4-related disease were included in this study. Women were affected in all analysed cases, with a mean age of 55.4 years. Two patients presented with the clinical involvement of more than one oral and maxillofacial anatomic site. Therefore, our sample comprised nine oral and maxillofacial anatomic sites affected by IgG4-related disease. The submandibular gland was affected in four cases, the tongue and the parotid gland in two cases each, and the palate in one case. In a few cases, exploratory lower lip biopsy was used as a diagnostic approach. A moderate-to-severe lymphoid infiltrate containing plasma cells and lymphocytes, with an increased IgG4/IgG ratio, was common. Treatment varied and steroids were the most frequently used (57.4%). Six patients remained alive, while one died from unknown causes. CONCLUSION: Although major salivary glands are commonly affected by IgG4-related disease, the oral cavity can also be involved, and lower lip biopsy may be an auxiliary diagnostic tool.

Hybrid odontogenic lesions: A systematic review of 203 cases reported in the literature.

BACKGROUND: Hybrid odontogenic lesions combine histopathological characteristics of two or more odontogenic cysts and/or tumours. The aim of this study was to evaluate the available data on hybrid odontogenic lesions (HOL) and to analyse their epidemiological/clinical features and biological behaviour. METHODS: An electronic search was done in January 2021 using multiple databases. Eligibility criteria encompassed publications with sufficient clinical and histological information to confirm the tumours' diagnoses. RESULTS: A total of 147 articles were included in this study, comprising 203 cases. Calcifying odontogenic cyst associated with odontoma (COC/OD) (37/18.2%) was the most common HOL. Females were more affected with a mean age of 24.9 years. Lesions presented as asymptomatic swellings, with a mean evolution time of 8.2 months (0.3-96), and mean tumour size of 4.8 cm (0.3-7). Radiographic aspects frequently showed radiolucent (139/68.4%) and unilocular (52/25.6%) images with well-defined limits (48/23.6%). The lesions mostly affected mandibular pre-molars (69/34%) and mandibular molars (69/34%) regions. Enucleation (89/43.8%) and surgical excision (59/29%) were the most common treatment modalities. The mean follow-up time was 33.8 months (0.5-216 months) and recurrences were observed in four cases (1.9%), all of which were central odontogenic fibroma associated with central giant cell granuloma (COF/CGCG). CONCLUSION: COC/OD is the most common HOL and recurrence is a rare event, being usually associated with the diagnosis of COF/CGCG.

Acquired oral syphilis: A multicenter study of 339 patients from South America.

OBJECTIVE: To report the clinicopathologic features of acquired oral syphilis cases in South American countries. MATERIALS AND METHODS: Clinical data were retrospectively collected from the records of 18 oral diagnostic services in Argentina, Brazil, Chile, Colombia, Venezuela, Uruguay, and Peru. Serologies of nontreponemal and treponemal tests were used for diagnosis. RESULTS: The series comprised 339 cases of acquired oral syphilis. Secondary syphilis ranked as the most common stage (86.7%). Lesions were more frequent among males (58.0%) and young adults with a mean age of 33.3 years. Individuals aged 20-29 years were most affected (35.3%). The most commonly involved sites were the tongue (31.6%), lip/labial commissure (25.1%), and hard/soft palate (20.4%). Clinically, acquired oral syphilis usually presented as mucous patches (28.4%), papules (25.7%), and ulcers (18.1%). Skin manifestations occurred in 67.7% of individuals, while lymphadenopathy and fever were observed in 61.3% and 11.6% of all subjects, respectively. Most patients were treated with the benzathine penicillin G antibiotic. CONCLUSION: This report validates the spread of acquired oral syphilis infection among young adults in South America. Our directives include accessible diagnostic tools for proper disease screening, surveillance, and counselling of affected individuals, especially in low- and middle-income countries.

Langerhans cell histiocytosis in the oral and maxillofacial region: An update.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disorder characterized by abnormal proliferation and infiltration of histiocytic cells. METHODS: This review focused on the main aspects associated with LCH. RESULTS: LCH can involve single or multiple organs and systems, with bone and skin being the most commonly affected sites. Regarding skeletal manifestations, the jawbones are involved in about 20%-30% of all cases. Such lesions may present as unilocular or multilocular images mainly affecting the posterior mandible. Oral soft tissue lesions may also occur, with the gingiva and hard palate being the most frequently affected sites. CONCLUSION: The diagnosis and management of LCH are challenging, requiring a multidisciplinary approach, with dentists playing a central role since oral manifestations can be the first sign of the condition.

Oral and oropharyngeal lymphomas: A multi-institutional collaborative study.

BACKGROUND: Lymphomas in the oral and oropharyngeal regions are relatively uncommon, and their diagnosis is challenging and complex due to the myriad histopathological subtypes. Herein, we report a large series of oral and oropharyngeal lymphomas and compare our data with the currently available literature. METHODS: All cases diagnosed as lymphomas affecting the oral and oropharyngeal regions were retrospectively retrieved from seven Brazilian institutions. Clinicodemographic data and histopathological features were evaluated and described, while a comprehensive literature review was undertaken in order to compare our findings. RESULTS: A total of 304 cases of oral and oropharyngeal lymphomas were obtained, mostly affecting individuals aged 60-69 years (n = 68) with a mean age at diagnosis of 54.2 ± 20.1 years. Males and females were equally affected. Mature B-cell neoplasms (87.2%) were the most common group, followed by mature T- and NK-cell neoplasms (11.2%) and precursor lymphoid neoplasms (1.6%). The most frequent subtypes in each group were diffuse large B-cell lymphomas, not otherwise specified (n = 99), extranodal NK/T-cell lymphomas, nasal type (n = 12), and B-lymphoblastic leukaemia/lymphomas, not otherwise specified (n = 4). The most commonly involved sites were the palate (26.3%), mandible (13%), and maxilla (10.5%). CONCLUSION: Diffuse large B-cell lymphoma, not otherwise specified, remains the most common subtype of lymphomas in the oral and oropharyngeal region. Older patients are the most affected, with no gender predilection and the palate and jaw are usually affected.

Burkitt lymphoma of the head and neck: An international collaborative study.

BACKGROUND: Burkitt lymphoma (BL) is an aggressive B-cell lymphoma with three variants (endemic, sporadic, and immunodeficiency-associated), presenting with specific epidemiological and clinical features. Burkitt lymphoma affects the head and neck region (BLHN) in approximately 10% of cases. The aim of this study was to undertake a comparative analysis of the clinicopathologic and immunohistochemical (IHC) features of BLHN diagnosed in patients from Africa, Guatemala, and Brazil. METHODS: Cases diagnosed as BLHN were collected from the files of six oral pathology laboratory services (Brazil, South Africa, and Guatemala) and one Brazilian pediatric oncology hospital from 1986 to 2020. Clinicopathological and IHC data, and Epstein-Barr virus (EBV) status by in situ hybridization data for each case were reviewed and described. RESULTS: Of the 52 cases, BLHN was predominant in pediatric patients [43 (82.69%)] and males [43 (82.69%)], with a mean age of 11.26 ± 9.68 years (range, 1-39 years). Neck and cervical lymph nodes [14 (26.92%)], and involvement of both maxilla and mandible [8 (15.38%)], were the most common anatomical sites. Clinically, tumor/swelling [40 (31.25%)], cervical lymphadenopathy [14 (10.94%)], pain [12 (9.38%)], and bone destruction [12 (9.38%)] were frequent findings. All cases showed typical morphological characteristics of BL. IHC profiles included positivity for CD20 [52 (100%)], CD10 [38 (79.17%)], Bcl6 [29 (87.88%)], and c-Myc protein [18 (81.82%)]. EBV was positive in 18 cases (62.07%). The Ki-67 index ranged from 90 to 100%. CONCLUSION: The clinicopathological and EBV profile of BLHN in South African, Guatemalan, and Brazilian patients is similar.

Plasmacytoma and plasma cell myeloma affecting the jaws: A multi-institutional collaborative study.

BACKGROUND: Plasma cell neoplasms are characterized by the proliferation of a single clone of plasma cells with production of a monoclonal immunoglobulin. They can manifest as a single lesion (plasmacytoma) or as multiple lesions (multiple myeloma). METHODS: Paraffin-embedded tissue blocks of patients microscopically diagnosed with plasma cell neoplasms in the jaws were retrieved from five pathology files. Data including clinical, radiographic, microscopic and immunohistochemical findings, treatment employed and follow-up status were retrieved from the pathology reports. RESULTS: Fifty-two cases were retrieved (mean age: 59.4 years) without sex predilection. The mandible was the most affected site (67.3%), usually associated with pain and/or paresthesia (53.8%). Lesions in other bones besides the jaws were reported for 24 patients (46.2%). Radiographically, tumours usually presented as poorly defined osteolytic lesions with unilocular or multilocular images, while microscopy revealed diffuse proliferation of neoplastic plasma cells with nuclear displacement and abundant eosinophilic cytoplasm. Two cases were classified as anaplastic, and amyloid deposits were found in two other cases. Immunohistochemistry was positive for plasma cell markers and negative for CD20 and CD3, and monoclonality for kappa light chain predominated. The overall survival rate after 5 years of follow-up was 26.6%. CONCLUSION: Plasma cell neoplasms are aggressive tumours with a poor prognosis and involvement of the jaws may be the first complaint of the patient. Thus, oral pathologists, head and neck surgeons and dentists should be aware of their clinical, radiographic and microscopic manifestations.

Mature T/NK-Cell lymphomas of the oral and maxillofacial region: A multi-institutional collaborative study.

BACKGROUND: The diagnosis of oral and maxillofacial mature T/NK-cell neoplasms is challenging because of their rarity, morphological heterogeneity and complex immunophenotype with scarce available data describing their clinical and microscopic aspects. Therefore, in this study, we investigated a series of mature T/NK-cell neoplasms affecting this anatomical region and provided an updated literature review. METHODS: Cases diagnosed as mature T/NK-cell lymphomas affecting the oral and maxillofacial region were retrospectively retrieved from six pathology files and their diagnoses were confirmed using haematoxylin and eosin-stained slides, immunohistochemical reactions and in situ hybridization for Epstein-Barr virus (EBV) detection. Patients' clinical data were collected from their pathology forms. RESULTS: A total of 22 cases were included in this study. Eleven (50%) consisted of extranodal NK/T-cell lymphomas, nasal type; eight (36.4%) were peripheral T-cell lymphomas, NOS; two (9.1%) were adult T-cell leukaemia/lymphomas, and one (4.5%) was an ALK-positive anaplastic large cell lymphoma. Overall, males predominated, with a mean age of 55.7 years. The palate was the most affected site (50%), and tumours usually presented as destructive and painful ulcers. EBV was present in all cases of extranodal NK/T-cell lymphoma nasal type but was absent in the other subtypes. CONCLUSION: Among mature T/NK-cell lymphomas of the oral and maxillofacial region, extranodal NK/T-cell lymphoma, nasal type and peripheral T-cell lymphoma, NOS predominated. Older men were the most affected patients, and this heterogeneous group of neoplasms has a very aggressive clinical behaviour.

KRAS mutations in brown tumor of the jaws in hyperparathyroidism.

BACKGROUND: Brown tumors are giant cell-rich lesions that result from abnormal bone metabolism in hyperparathyroidism, one of the most common endocrine disorders worldwide. Brown tumors occasionally affect the jaws and, despite well-known clinical and microscopic features, their molecular pathogenesis remains unclear. We investigated the presence of pathogenic activating mutations in TRPV4, FGFR1, and KRAS in a cohort of brown tumors since these have recently been reported in giant-cell lesions of the jaws and non-ossifying fibromas of the bones (FGFR1 and KRAS), which are histologic mimics of brown tumors. METHODS: We target sequenced 13 brown tumors of the jaws associated with primary or secondary hyperparathyroidism. As mutations in these genes are known to activate the MAPK/ERK signaling pathway, we also assessed the immunostaining of the phosphorylated form of ERK1/2 (pERK1/2) in these lesions. RESULTS: KRAS pathogenic mutations were detected in seven cases (p.G12V n = 4, p.G12D n = 1, p.G13D n = 1, p.A146T n = 1). KRAS variants of unknown significance (VUS), p.A134T and p.E37K, were also detected. All samples showed wild-type sequences for FGFR1 and TRPV4 genes. The activation of the MAPK/ERK signaling pathway was demonstrated by pERK1/2 immunohistochemical positivity of the brown tumors´ mononuclear cells. CONCLUSION: Mutations in KRAS and activation of the MAPK/ERK signaling pathway were detected in brown tumors of hyperparathyroidism of the jaws, expanding the spectrum of giant cell lesions whose molecular pathogenesis involve RAS signaling.

A Brazilian multicentre study of 2,497 isolated cases of odontogenic keratocysts.

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.

A multicenter study of oral sarcomas in Brazil.

OBJECTIVES: The aim of this study was to investigate the prevalence of oral sarcomas from geographic regions of Brazil. MATERIALS AND METHODS: A cross-sectional study was conducted on biopsies obtained from January 2007 to December 2016 at twelve Brazilian oral and maxillofacial pathology centres. Gender, age, evolution time, clinical aspects, tumour location, tumour size at diagnosis, radiographic aspects and histopathological diagnosis were evaluated. Data were analysed using descriptive statistical methods. RESULTS: From 176,537, a total of 200 (0.11%) oral sarcomas were reported, and the most prevalent were osteosarcomas (74 cases; 37%) and Kaposi's sarcomas (52 cases; 26%). Males were more affected than females at a mean age of 32.2 years old (range of 3-87 years). The most common symptoms were swelling¸ localised pain and bleeding at a mean evolution time of 5.14 months (range <1-156 months). The lesions were mostly observed in the mandible (90 cases; 45%), with a mean tumour size of 3.4 cm (range of 0.3-15 cm). Radiographically, the lesions presented a radiolucent aspect showing cortical bone destruction and ill-defined limits. CONCLUSIONS: Oral sarcomas are rare lesions with more than 50 described subtypes. Osteosarcomas and Kaposi's sarcomas were the main sarcomas of the oral cavity in Brazil.

KRAS mutations drive adenomatoid odontogenic tumor and are independent of clinicopathological features.

Adenomatoid odontogenic tumor is a benign encapsulated epithelial odontogenic tumor that shows an indolent clinical behavior. We have reported in a few adenomatoid odontogenic tumors mutations in KRAS, which is a proto-oncogene frequently mutated in cancer such as lung, pancreas, and colorectal adenocarcinomas. We aimed to assess KRAS mutations in the hotspot codons 12, 13, and 61 in a large cohort of adenomatoid odontogenic tumors and to test the association of these mutations with clinical (age, site, tumor size, follicular/extrafollicular subtypes) and histopathological parameters. Thirty eight central cases were studied. KRAS codon 12 mutations were assessed by TaqMan allele-specific qPCR (p.G12V/R) and/or Sanger sequencing, and codon 13 and 61 mutations were screened by Sanger. Histological tumor capsule thickness was evaluated by morphometric analysis. Additionally, the phosphorylated form of the MAPK downstream effector ERK1/2 was investigated. Statistical analysis was carried out to test the association of KRAS mutations with clinicopathological parameters. KRAS c.35 G >T mutation, leading to p.G12V, was detected in 15 cases. A novel mutation in adenomatoid odontogenic tumor, c.34 G >C, leading to p.G12R, was detected in 12 cases and the other 11 were wild-type. Codon 12 mutations were not associated with the clinicopathological parameters tested. RAS mutations are known to activate the MAPK pathway, and we show that adenomatoid odontogenic tumors express phosphorylated ERK1/2. In conclusion, a high proportion of adenomatoid odontogenic tumors (27/38, 71%) have KRAS codon 12 mutations, which occur independently of the clinicopathological features evaluated. Collectively, these findings indicate that KRAS mutations and MAPK pathway activation are the common features of this tumor and some cancer types. Although it is unclear why different codon 12 alleles occur in different disease contexts and the complex interactions between tumor genotype and phenotype need clarification, on the basis of our results the presence of KRAS p.G12V/R favors the adenomatoid odontogenic tumor diagnosis in challenging oral neoplasm cases.