Contribution of public oral pathology services to the diagnosis of oral and oropharyngeal cancer in Brazil.

This study aimed to evaluate the contribution of oral and maxillofacial pathology laboratories (OMPLs) in Brazilian public universities to the diagnosis of lip, oral cavity, and oropharyngeal squamous cell carcinoma (SCC). A cross-sectional study was performed using biopsy records from a consortium of sixteen public OMPLs from all regions of Brazil (North, Northeast, Central-West, Southeast, and South). Clinical and demographic data of patients diagnosed with lip, oral cavity, and oropharyngeal SCC between 2010 and 2019 were collected from the patients' histopathological records. Of the 120,010 oral and maxillofacial biopsies (2010-2019), 6.9% (8,321 cases) were diagnosed as lip (0.8%, 951 cases), oral cavity (4.9%, 5,971 cases), and oropharyngeal (1.2%, 1,399 cases) SCCs. Most cases were from Brazil's Southeast (64.5%), where six of the OMPLs analyzed are located. The predominant profile of patients with lip and oral cavity SCC was Caucasian men, with a mean age over 60 years, low schooling level, and a previous history of heavy tobacco consumption. In the oropharyngeal group, the majority were non-Caucasian men, with a mean age under 60 years, had a low education level, and were former/current tobacco and alcohol users. According to data from the Brazilian National Cancer Institute, approximately 9.9% of the total lip, oral cavity, and oropharyngeal SCCs reported over the last decade in Brazil may have been diagnosed at the OMPLs included in the current study. Therefore, this data confirms the contribution of public OMPLs with respect to the important diagnostic support they provide to the oral healthcare services extended by the Brazilian Public Health System.

Cell block preparation as an adjunctive tool after fine-needle aspiration cytology for screening oral and maxillofacial diseases.

OBJECTIVE: To describe the use of cell block (CB) preparation from fine-needle aspiration cytology for diagnosing oral and maxillofacial diseases. STUDY DESIGN: We performed a retrospective analysis of 568 samples collected by our laboratory for CB preparation from fine-needle aspiration cytology of the oral and maxillofacial region between January 2001 and October 2021. We performed cytologic diagnoses and compared them with the available histopathologic diagnoses to calculate the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CB preparation for identifying malignant lesions. RESULTS: The most frequent diagnosis was pleomorphic adenoma (n = 44, 7.7%), followed by metastatic squamous-cell carcinoma (n = 28, 4.9%) and odontogenic keratocyst (n = 26, 4.6%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CB preparation, which revealed detailed morphologic and architectural patterns, were 70.0%, 100.0%, 100.0%, 62.5%, and 80.0%, respectively. CONCLUSIONS: Cell block preparation from fine-needle aspiration cytology of the oral and maxillofacial region may be a useful adjunctive diagnostic tool for diagnosing oral and maxillofacial diseases because it reveals morphologic and architectural patterns similar to those shown on histopathologic slides, leading to the better categorization of diseases.

Factors related to the waiting time for scheduling an oral biopsy in Brazil: a multilevel analysis.

BACKGROUND: Timely diagnosis of oral cancers is critical, and performing biopsies of oral lesions with suspected malignancy is a crucial step in achieving this goal. The waiting time for the diagnosis may be related to the progression and prognosis of malignant neoplasms. OBJECTIVE: The aim of this observational, cross-sectional, national-level study was to identify the factors associated with the waiting time for scheduling an oral biopsy, based on the identification of its need. METHODS: We used secondary data from the Brazilian public health system, obtained from the 2nd cycle of the National Program to Improve Access and Quality of Dental Specialty Centers (PMAQ-CEO). The study outcome was the waiting time for scheduling an oral biopsy, starting from the identification of the need for the exam. We analyzed individual and contextual variables using multilevel statistical analysis. RESULTS: In 51.8% of DSC the waiting time for scheduling a biopsy was non-immediate; in 58.1% of CEOs, the sum of the weekly workload of dentists working in the Stomatology specialty is up to 20 h per week; in terms of coverage, 67.1% of the CEOs have only municipal coverage and 34.0% are references for up to 12 oral health teams in primary health care; only the coverage variable remained significant in the multivariate model (p < 0.05). Of the contextual variables, none of the variables remained significant (p > 0.05). When these were analyzed together, only the coverage remained significant (p < 0.05); CONCLUSION: Our analysis indicates that the waiting time for scheduling an oral biopsy is longer in CEOs that cover only one municipality and is not related to contextual factors.

Hamartomatous Polyp of the Palatine Tonsil: A Case Report and Critical Literature Review.

BACKGROUND: Hamartomatous polyp of the palatine tonsil is a rare benign tumor poorly recognized by clinicians and pathologists. We present a novel case report and provide a literature review about this diagnosis, highlighting its clinicopathological features and treatment modalities. METHODS: We herein report a case of a 22-year-old female patient who complained of a foreign body sensation in her throat. She presented with a pedunculated polyp attached to her right palatine tonsil, which was noticed 15 years ago. An excisional biopsy was performed under local anesthesia, and the microscopic aspect confirmed the diagnosis of the hamartomatous polyp of the palatine tonsil. The literature review was performed using the "palatine tonsil polyps" term in PubMed and Google Scholar. Only English-language publications showing clinical and microscopic descriptions were selected as inclusion criteria. RESULTS: As in our case report, this poorly understood lesion usually presents as a solitary, unilateral pedunculated mass attached to the palatine tonsil surface with nonspecific symptoms. The literature shows less than 100 cases reported, which reveals a lesion preference for male and young adult patients. Microscopically, it is characterized by disorganized proliferation of the connective tissue components indigenous to the involved site, with variable lymphangiectasia, which accounts for the diversity of the diagnostic term and its unknown incidence. Its treatment consists of excision of the polyp with or without tonsillectomy, and no recurrence or malignant transformation of these polyps has been reported. CONCLUSION: The hamartomatous polyp of the palatine tonsil is challenging due to its rarity and lack of standardization of the terminology used in the literature. Including this diagnosis in the 5th edition of the World Health Organization Classification for Head and Neck Tumors is expected to contribute to a better understanding of this pathology.

Contribution of public oral pathology services to the diagnosis of oral and oropharyngeal cancer in Brazil

Abstract This study aimed to evaluate the contribution of oral and maxillofacial pathology laboratories (OMPLs) in Brazilian public universities to the diagnosis of lip, oral cavity, and oropharyngeal squamous cell carcinoma (SCC). A cross-sectional study was performed using biopsy records from a consortium of sixteen public OMPLs from all regions of Brazil (North, Northeast, Central-West, Southeast, and South). Clinical and demographic data of patients diagnosed with lip, oral cavity, and oropharyngeal SCC between 2010 and 2019 were collected from the patients' histopathological records. Of the 120,010 oral and maxillofacial biopsies (2010-2019), 6.9% (8,321 cases) were diagnosed as lip (0.8%, 951 cases), oral cavity (4.9%, 5,971 cases), and oropharyngeal (1.2%, 1,399 cases) SCCs. Most cases were from Brazil's Southeast (64.5%), where six of the OMPLs analyzed are located. The predominant profile of patients with lip and oral cavity SCC was Caucasian men, with a mean age over 60 years, low schooling level, and a previous history of heavy tobacco consumption. In the oropharyngeal group, the majority were non-Caucasian men, with a mean age under 60 years, had a low education level, and were former/current tobacco and alcohol users. According to data from the Brazilian National Cancer Institute, approximately 9.9% of the total lip, oral cavity, and oropharyngeal SCCs reported over the last decade in Brazil may have been diagnosed at the OMPLs included in the current study. Therefore, this data confirms the contribution of public OMPLs with respect to the important diagnostic support they provide to the oral healthcare services extended by the Brazilian Public Health System.

MutSα expression predicts a lower disease-free survival in malignant salivary gland tumors: an immunohistochemical study

Ten cases of normal salivary gland (NSG) and 92 of SGT (54 benign and 38 malignant) were retrieved. Immunohistochemistry was performed for hMSH2, hMSH3, hMSH6. Scanned slides were digitally analyzed based on the percentage of positive cells with nuclear staining. Cases were further classified in MutSαhigh and MutSβhigh based on hMSH2-hMSH6 and hMSH3-hMSH6 expression, respectively. Results: hMSH3 expression was lower in malignant SGT compared to NSG and benign cases. Adenoid cystic carcinoma (ACC) cases with perineural invasion presented a lower percentage of hMSH3 positive cells. hMSH6 was downregulated in both benign and malignant SGT compared to NSG. Malignant SGT cases with MutSαhigh expression had lower disease-free survival compared to MutSαlow cases. A 10.26-fold increased risk of presenting local recurrence was observed. Conclusions: Our findings suggest that a lack of hMSH3 protein function is associated with a more aggressive phenotype (malignancy and perineural invasion) and that MutSα overexpression predicts a poor clinical outcome in malignant SGT.(AU)

DNA methylation status of MutS genes in ameloblastoma.

OBJECTIVES: Ameloblastoma is an odontogenic epithelial tumour with a low expression of mismatch repair system components. We aimed to investigate the methylation status of the genes MSH2, MSH3 and MSH6 (MutS group) in conventional ameloblastomas. MATERIALS AND METHODS: The ameloblastoma and dental follicle samples (n = 10 each) were collected from 20 different patients. Each ameloblastoma sample was sectioned into two fragments: one was paraffin-embedded while the other one, likewise the dental follicle samples, was fixed in RNAlater and frozen at -196°C. All frozen samples were investigated for the MutS genes methylation levels, using the enzymatic restriction digestion and quantitative real-time PCR (qPCR) assay. The ameloblastoma paraffin-embedded samples were submitted to immunohistochemical reactions for MutS proteins detection and digitally quantification. Correlation analyses were performed between the immunohistochemical results and the respective gene methylation percentage. RESULTS: There are no significant differences between the MutS genes methylation levels in the ameloblastoma and the dental follicle. However, a strong negative correlation was found between MSH2 and MSH6 gene methylation status and their respective proteins expressions evaluated by immunohistochemistry. CONCLUSION: Our results show that the genes methylations is in part responsible for decreasing the expression of MSH2 and MSH6 genes in ameloblastoma.

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.

Prognostic significance of CD30 expression in diffuse large B-cell lymphoma: A systematic review with meta-analysis.

BACKGROUND: CD30 is variably expressed in diffuse large B-cell lymphoma (DLBCL), but its prognostic potential for the affected patients remains debatable and unclear. Therefore, we aimed to determine the frequency of CD30 expression in DLBCL and its potential for prognostic determination. METHODS: An electronic systematic review was performed using multiple databases, followed by a quantitative meta-analysis to assess the frequency of CD30 expression with positivity cut-off values of >0% and >20%, and to determine its association with clinicopathological features and patients' survival. RESULTS: Using a cut-off value >0%, we observed that 3.5%-59.1% of the cases were considered positive for CD30. There was a significant association of the protein expression with a lower number of extra-nodal sites affected by the neoplasm, with Ann Arbor advanced stage, the absence of B-symptoms, the lack of MYC and BCL2 translocations, and a lower ECOG performance. Using a cut-off value >20%, we observed that 2.5%-36.7% of the cases were considered positive for CD30, being significantly associated with a lower number of extra-nodal sites affected by the neoplasm, Ann Arbor stages III/IV, non-GCB tumours, the lack of MYC and BCL2 translocations, and a lower ECOG value. CD30 expression was significantly associated with a better survival rate, regardless of what cut-off parameter was used. CONCLUSION: Despite variations in the cut-off values used to determine CD30 positivity in DLBCL, the expression of this protein seems to be associated with a higher survival rate and better prognosis.

Immunohistochemical Expression of Fatty Acid Synthase (FASN) is Correlated to Tumor Aggressiveness and Cellular Differentiation in Salivary Gland Carcinomas.

Fatty acid synthase (FASN) expression is closely related to cancer progression, in particular, tumor aggressiveness and poor prognosis. This study aimed to analyse the expression of FASN in carcinomas of the salivary glands and correlate it with Ki-67 expression. We analysed by immunohistochemistry the expression of FASN and Ki-67 on tissue sections from 7 cases of adenocarcinoma, not otherwise specified (AdNOS), 6 cases of polymorphous adenocarcinoma (PAC), 16 cases of acinic cell carcinoma (AcCC), 19 cases of adenoid cystic carcinoma (AdCC), 15 cases of epithelial-myoepithelial carcinoma (EMC); 10 cases of secretory carcinoma (SC), 13 cases of mucoepidermoid carcinoma (MEC), 10 cases of salivary duct carcinoma (SDC) and 7 cases of myoepithelial carcinoma (MC). These carcinomas were classified into aggressive and indolent regarding their biological behaviour. Additionally, MEC and AdCC were also classified according to the histological grade. High expression of FASN was found in SDC (100%), SC (100%), AcCC (68.7%) and AdNOS (57.2%). No association was found between FASN and Ki-67 expression. Aggressive carcinomas showed a higher rate of Ki-67 proliferation (p < 0.001) and greater expression of FASN when compared to indolent carcinomas (p < 0.05). With regards to carcinomas categorized as indolent, FASN expression was much higher in the lesions that presented cell differentiation (SC and AcCC). Also, FASN expression was significantly higher in high-grade AdCC and MEC when compared to low-grade tumors (p < 0.05). We concluded that FASN expression was correlated to tumor aggressiveness and cellular differentiation in salivary gland carcinomas.

Fully digital pathology laboratory routine and remote reporting of oral and maxillofacial diagnosis during the COVID-19 pandemic: a validation study.

The role of digital pathology in remote reporting has seen an increase during the COVID-19 pandemic. Recently, recommendations had been made regarding the urgent need of reorganizing head and neck cancer diagnostic services to provide a safe work environment for the staff. A total of 162 glass slides from 109 patients over a period of 5 weeks were included in this validation and were assessed by all pathologists in both analyses (digital and conventional) to allow intraobserver comparison. The intraobserver agreement between the digital method (DM) and conventional method (CM) was considered almost perfect (κ ranged from 0.85 to 0.98, with 95% CI, ranging from 0.81 to 1). The most significant and frequent disagreements within trainees encompassed epithelial dysplasia grading and differentiation among severe dysplasia (carcinoma in situ) and oral squamous cell carcinoma. The most frequent pitfall from DM was lag in screen mirroring. The lack of details of inflammatory cells and the need for a higher magnification to assess dysplasia were pointed in one case each. The COVID-19 crisis has accelerated and consolidated the use of online meeting tools, which would be a valuable resource even in the post-pandemic scenario. Adaptation in laboratory workflow, the advent of digital pathology and remote reporting can mitigate the impact of similar future disruptions to the oral and maxillofacial pathology laboratory workflow avoiding delays in diagnosis and report, to facilitate timely management of head and neck cancer patients. Graphical abstract.

Oral and oropharyngeal diffuse large B-cell lymphoma and high-grade B-cell lymphoma: A clinicopathologic and prognostic study of 69 cases.

OBJECTIVE: The objective of this study was to describe the clinicopathological, molecular, and prognostic features of oral/oropharyngeal diffuse large B-cell lymphoma (DLBCL) and high-grade B-cell lymphoma. STUDY DESIGN: All cases were retrieved from 7 Brazilian institutions. Immunohistochemical reactions were performed to confirm the diagnoses and to categorize the tumors. In situ hybridization was used to detect Epstein-Barr virus (EBV) and fluorescence in situ hybridization was used to identify gene rearrangements. RESULTS: Most cases involved the oral cavity (76.8%). Males and females, with a mean age of 60 years, were evenly affected. Tumors mostly presented as painful swellings. Forty cases represented germinal center B-cell type (58%). Five cases presented double-hit translocation and 3 harbored rearrangement for MYC/BCL2/BCL6. EBV was detected in 3 cases (4.3%). The 5-year overall survival was 44.4%. Female sex, presence of pain and ulcer, microscopic "starry sky pattern" and necrosis, co-expression of c-Myc/Bcl2, and translocation of MYC were associated with a lower survival in univariate analysis (P = .05, P = .01, P = .01, P = .03, P = .05, P = .006, P = .05, respectively). CONCLUSION: Patients affected by oral/oropharyngeal DLBCL have a low survival rate. High-grade B-cell lymphoma (17.7%) and EBV-positive DLBCL, not otherwise specified (4.3%) account for a small number of cases.

Metastatic Neuroblastoma to the Mandible of Children: Report of Two Cases and Critical Review of the Literature.

Neuroblastoma is the most common extracranial solid cancer of infancy, occurring mainly in the adrenal gland, with high metastatic potential. However, involvement of the head and neck region is rare. Here, we present two cases of metastatic neuroblastoma of childhood, in which a mandibular swelling was the first sign of disseminated disease. Case 1 describes a 4-year-old boy with a 2-week history of painful swelling in the left mandibular region, body soreness and weakness. Panoramic radiography and computed tomography showed a destructive lesion in the left mandibular ramus. Case 2 describes a 3-year-old boy with a 1-month history of swelling in the right mandibular area. Panoramic radiograph and cone-beam computed tomography showed a destructive lesion in the right body and ramus of the mandible, displacing tooth germs, with the destruction of vestibular and lingual bone cortices. In both cases, microscopic analyses revealed a diffuse proliferation of small, round, and blue cells with hyperchromatic nuclei and scant cytoplasm. While Case 1 was more undifferentiated, Case 2 presented eosinophilic areas suggestive of neuropil. A large immunohistochemical panel was performed, showing expression of neural markers such as CD56, neuron-specific enolase (in Case 2), chromogranin, and synaptophysin. Both lesions presented a high proliferation index (Ki67 > 70% and 80%, respectively). Positron emission tomography-computed tomography revealed ipsilateral adrenal primary lesions in both cases, with multiple bone metastatic lesions. Besides the mandible, multiple sites of the axial and appendicular skeleton were affected. Treatment consisted of induction chemotherapy, adrenalectomy, consolidation chemoradiotherapy, and post-consolidation therapy.

Expression of DNMTs and H3K9ac in Ameloblastoma and Ameloblastic Carcinoma.

Objectives: DNA methyltransferases (DNMTs) and the histone modification H3K9ac are epigenetic markers. This study aimed to describe the immunohistochemical expression of DNMT1, DNMT3A, DNMT3B, and H3K9ac in the dental follicle (DF), ameloblastoma (AME), and ameloblastic carcinoma (AC), correlating these expressions with the recurrence and aggressive behavior in ameloblastoma. Study Design: Immunohistochemical reactions were performed in 10 human DFs, 38 ameloblastomas, and 6 AC samples. Another 59 ameloblastomas assembled in a tissue microarray were used to compare the immunoexpression with the clinical, radiographic, and histopathological characteristics and the presence of BRAFv600e mutation. Each slide was digitized as a high-resolution image and quantified by Aperio ScanScope Nuclear V9 software. All statistical analyzes were performed using GraphPad Prism statistical software. Results: DNMT3B expression was higher in ameloblastomas than in the DFs, while the AC overexpressed all proteins. The ameloblastomas with BRAFv600e mutation, vestibular/lingual, or vestibular/palatine bone cortical disruption and maxilla involvement showed DNMT1 overexpression, while recurrent cases had high DNMT3B levels. Conclusions: DNA methylation and histone modification might play a role in the development, clinical aggressiveness, and recurrence rates of ameloblastoma, such as the progression to AC. Further investigation about gene methylations in ameloblastomas is needed to better understand its relationship with aggressiveness and recurrence.

Central odontogenic fibroma: an international multicentric study of 62 cases.

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

An audit of cytopathology in the oral and maxillofacial region: 18 years of experience.

INTRODUCTION: The aim of this study was to perform an audit of oral and maxillofacial specimens submitted for cytological diagnosis to verify the importance of this complementary examination. METHODS: A retrospective analysis of our institutional cytopathology database was performed over an 18-year period. Clinical information and cytological data were collected. Associations between independent variables and outcomes were assessed using the Pearson χ2 test or Fisher's test, with a 5% significance level. When available, the histological diagnosis was compared with cytological diagnosis to identify the percentage of agreement and the specificity, sensitivity and accuracy of cytology in identifying malignant neoplasms. RESULTS: A total of 1082 cases were identified, which included 65 different cytological diagnoses. Exfoliative cytology (EC) was performed in 312 cases (29.1%) and fine needle aspiration cytology (FNAC) in 770 cases (70.9%). EC was mainly employed to diagnose oral infectious diseases (P < 0.001) and FNAC to diagnose neoplasms, cystic, reactive and miscellaneous lesions (P < 0.001). Cell-block was performed in 555 FNAC cases (51.3%). Panoptic, Papanicolaou and haematoxylin-eosin staining were performed in FNAC and periodic acid-Schiff in EC (P < 0.001). In 211 cases (19.5%), the histological diagnosis was available and the percentage agreement with the cytological diagnosis was 41.2%. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to identify malignant neoplasms were 84.6%, 100%, 100%, 77.8% and 90.0%, respectively. CONCLUSIONS: EC was mainly performed for diagnosis of infectious diseases and FNAC for diagnosis of salivary gland tumours, odontogenic lesions, reactive lesions and cervical metastasis.

ß-catenin and Its Relation to Alveolar Bone Mechanical Deformation - A Study Conducted in Rats With Tooth Extraction.

The aim of this study was to analyze the relationship between alveolar bone deformation and ß-catenin expression levels in response to the mechanical load changed by dental extraction in adult rats. Twenty-four male rats (Rattus norvegicus albinus), Wistar linage, at 2 months of age, were used. The right upper incisor tooth was extracted, and euthanasia occurred in periods 5 (n = 6), 7 (n = 6), and 14 (n = 6) days after Day 0. In the control group (n = 6), the dentition was maintained. The euthanasia occurred within 14 days after day 0. After euthanasia, the rats of all groups had their left jaw with tooth removed and separated in the middle. The pieces were undergone routine histological processing and then the immunohistochemical marking were performed to label expression of the primary ß-catenin antibody, which was evaluated by qualitative and quantitative analysis. One head by each group (control and experimental) was submitted to computerized microtomography. After the three-dimensional reconstruction of the skull of the rat in each group, the computational simulation for finite elements analysis were performed to simulate a bite in the incisors. In finite element analysis, the strain patterns were evaluated after the application of bite force. The results were analyzed considering the areas in which changes in the amount of deformations were detected. The action of the bite force in the experimental condition, resulted in a uniform distribution of the amount of deformations, in addition to lower amount of deformation areas, differentiating from the control group. Comparing with the control group, the levels of ß-catenin signaled in the lingual bone of the middle third of the alveolar bone were raised in the periods of 5 and 14 days. The increased ß-catenin positive staining intensity was concentrated on osteocytes and gaps of osteocytes. The findings of the present study were in accordance with our hypothesis that the condition of dental extraction can cause the expression of ß-catenin and alter the regimes of bone deformation.

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.

Massive extrusion of calcium hydroxide paste containing barium sulphate during endodontic treatment.

A 31-year-old woman was referred for the evaluation of persistent lower lip numbness following endodontic treatment of tooth #36. Imaging examinations showed a large amount of radiopaque/hyperdense material spread in an angiographic distribution in the left mandibular body region. Laboratory analyses of tooth #36 and adjacent periapical tissue, surgically extracted in an external Service due to acute pain following endodontic treatment, identified chronic inflammatory reaction and birefringent crystalloid foreign bodies rich in barium and sulphur, leading to the diagnosis of alveolar nerve injury due to accidental extrusion of intracanal dressing material composed of calcium hydroxide [Ca(OH)2 ] paste incorporated with barium sulphate. Clinicians should be aware that Ca(OH)2 when in contact with periapical tissues may lead to persistent toxicities, such as necrosis, pain and paraesthesia. Therefore, injectable Ca(OH)2 systems should be used with caution because they can cause paste extrusion and damage to the lower alveolar nerve.

Activation of BDNF/TrkB/Akt pathway is associated with aggressiveness and unfavorable survival in oral squamous cell carcinoma.

OBJECTIVES: To evaluate the expression of brain-derived neurotrophic factor (BDNF), its tyrosine kinase receptor B (TrkB), and two downstream targets of this pathway, Akt and ribosomal protein S6 (RPS6), in normal oral mucosa (NOM), oral leukoplakia (OL), and oral squamous cell carcinoma (OSCC) and correlate this expression with OSCC patients' outcomes, cell senescence, and "stemness" profile. MATERIALS AND METHODS: Ten cases of NOM, 32 OL, and 72 primary OSCC were included. Immunohistochemical analysis for BDNF, TrkB, p-TrkB, p-Akt, and p-RPS6 was performed. Cell senescence and stemness profile of OSCC were evaluated through p16 and BMI-1 immunohistochemical expression, respectively. The slides were scanned into high-resolution images and quantified through digital analysis. RESULTS: Oral squamous cell carcinoma presented increased expression of BDNF/TrkB/Akt pathway compared to NOM and OL. OSCC diagnosed in advanced clinical stages presented an upregulation of BDNF and p-TrkB. BDNF and p-Akt were identified as predictors of poor disease-specific survival. The increase in stemness profile was correlated with a decrease in p-TrkB and p-Akt expression. CONCLUSIONS: BDNF/TrkB/Akt pathway is significantly increased in malignant cells from OSCC. Moreover, BDNF and Akt represent biomarkers capable to predict a poor prognosis of OSCC patients.