Hélder Antônio Rebelo Pontes

Plasmablastic lymphoma (PBL) is an aggressive neoplasm in which MYC rearrangements are frequent, whereas concurrent BCL2 and/or BCL6 rearrangements are poorly characterized. We investigated MYC , BCL2 and BCL6 rearrangements in a Brazilian series of oral PBL. Thirty cases were confirmed morphologically and immunophenotypically; 23 were evaluable for fluorescence in situ hybridization. MYC rearrangement was detected in 56.5% of the cases. Three tumors harbored concurrent MYC / BCL2 rearrangements and one harbored MYC / BCL2 / BCL6 rearrangements (17.3%). Targeted review of the available sections from these four cases showed no evidence of residual low-grade B-cell lymphoma, follicular architecture, or morphologically distinct component suggesting transformation. These findings expand the cytogenetic spectrum of oral PBL, highlighting some molecular overlap with other high-grade B-cell lymphomas.

Objectives: This study aimed to investigate the clinicopathological features of malignant odontogenic tumors (MOTs) and to provide a comprehensive characterization that enhances the current understanding of this disease group. Methods: MOTs were retrieved from six Brazilian oral pathology services between 2007 and 2025. Demographic, clinical and radiographic data were collected from the charts, and the histological H&E-stained sections were revised by two blinded pathologists; previously available immunohistochemical and molecular findings were retrieved and reviewed in selected cases and the diagnosis was established according to the 2022 World Health Organization classification. Results: A total of 53 malignant odontogenic tumors were identified, predominantly affecting the mandible (83%), with a slight male predominance (male-to-female ratio, 1.12:1) and a mean age of 41.4 years. Ameloblastic carcinoma was the most frequent subtype (58.5%), followed by clear cell odontogenic carcinoma (18.9%), ameloblastic fibrosarcoma (13.2%), primary intraosseous carcinoma (7.5%), and ghost cell odontogenic carcinoma (1.9%). Conclusions: This multicenter review summarizes the main features of malignant odontogenic tumors. Although rare, these tumors often exhibit locally aggressive behavior, highlighting the need for early diagnosis, accurate histopathological evaluation, and standardized reporting with long-term follow-up.

Background/Aim: Facial trauma is a major public health challenge due to its aesthetic, functional, psychological, and socioeconomic impacts. In Northern Brazil, particularly in the Amazon region, subsistence activities such as plant extraction, animal handling, and river transportation are essential to daily life and may contribute to an increased risk of facial injuries. These environmental and cultural factors are often underrepresented in the literature. This study aimed to investigate the epidemiological profile of facial fractures associated with etiologies specific to the Amazon region. Materials and Methods: This was a retrospective study conducted over an 8‐year period (2013–2020) at a trauma referral center in Northern Brazil. Medical records of patients with facial fractures resulting from boat accidents, animal‐related incidents, plant extraction, and hunting and fishing accidents were reviewed. Results: A total of 97 patients met the inclusion criteria, with males accounting for 88.7% of cases and adults (20–64 years) being the most affected age group. Boat accidents were the most frequent cause of trauma (40.2%) and were associated with a higher median number of surgical fractures compared to animal‐related trauma ( p = 0.041) and hunting and fishing accidents ( p < 0.001). The middle third of the face was most commonly affected (78%), and the mean FISS score was 4.4. The average length of hospital stay was 11 days, with a significant correlation between FISS and hospital stay ( p = 0.0078). Hunting and fishing accidents were the leading cause of long‐term sequelae. Conclusion: Facial fractures related to the Amazon region are associated with distinct occupational and environmental risks, imposing not only a burden on public health but also resulting in specific morbidities within traditional populations. Although these injuries do not necessarily reflect the characteristics of the broader population, they highlight the need for public policies tailored to the regional context.

Objective: To investigate the potential of machine learning systems for the clinical classification of palatal salivary gland tumors into five diagnostic categories using only demographic and clinical data. Methods: Four machine learning models—Multilayer Perceptron (MLP), Support Vector Machine (SVM), Random Forest (RF), and XGBoost—were implemented based on demographic and clinical attributes from 100 patients. The methodology involved a four‐step process: Hyperparameter optimization using systematic search for combinations (Grid Search), fivefold cross‐validation comprising training and testing, classifier training, and tests, followed by the acquisition of standardized performance metrics. The input attributes included age, sex, location, and symptoms. Performance was evaluated using accuracy, macro‐average sensitivity, specificity, precision, and F1‐score. Results: According to the mean accuracy values, XGBoost and MLP achieved the highest performance (81%), followed by SVM (80%) and RF (79%). Nevertheless, for all models, both macro‐averaged sensitivity and F1‐score were relatively low, remaining below 75%. Specificity emerged as the most consistent metric, ranging from 85% to 90% across all classifiers. All models reached a perfect score (1.0) in the classification of PA, whereas performance declined for malignant tumors, particularly for the rarer subtypes. Conclusions: Machine learning is a feasible approach for classifying palatal salivary gland tumors, demonstrating high specificity but limited sensitivity, primarily due to the uneven distribution of tumor subclasses, particularly the malignant ones, which are underrepresented owing to their rarity. XGBoost proved to be the most robust model with a low computational cost.

Plasmablastic lymphoma (PBL) is a rare and aggressive non-Hodgkin lymphoma with a poor prognosis and short survival rates. It is classified as a large B-cell lymphoma subtype, but carries a plasmacytic immunophenotype. Therefore, PBL has pathogenetic overlaps with diffuse large B-cell lymphoma not otherwise specified (DLBCL NOS) and plasma cell neoplasms (PCNs). Although recent studies have characterized important genetic abnormalities in PBL, the precise molecular mechanisms driving its pathogenesis remain elusive. In this study, we analyzed 607 inflammatory genes in 10 PBL, 11 DLBCL NOS/high-grade B-cell lymphoma (DLBCL NOS/HGBCL), and 11 PCN samples to uncover the PBL immunoregulatory landscape and to identify promising therapeutic target candidates. Several differentially expressed genes were observed, including STAT4, STAT5A, and MAPK14, with enriched pathways such as JAK-STAT, nuclear factor-kappa B (NF-κB), and complement signaling in the PBL group. Notably, CR2 was underexpressed in PBL compared to DLBCL NOS/HGBCL and PCNs, suggesting a restricted Wp latency stage of Epstein–Barr virus (EBV), which may contribute to immune evasion. Functional analyses identified key immune pathways, including cytokine–receptor interactions, Toll-like receptor signaling, and neutrophil extracellular trap formation, with protein–protein interaction networks, emphasizing complement activation and JAK-STAT signaling pathways. In conclusion, oral PBL exhibits a complex inflammatory gene expression profile, and key signaling pathways, particularly JAK-STAT, NF-κB, and complement activation, are enriched in this tumor compared to DLBCL NOS/HGBCL and PCNs.

Oral Squamous Cell Carcinoma (OSCC) is the most common malignant tumor of the oral cavity. It can be preceded by Oral leukoplakia (OL), the most prevalent potentially malignant disorder, which presents a malignant transformation rate which varies from 1,1 to 40,8%, found most commonly in tongue lesions. Smoking is a well-established risk factor for both OL and OSCC. In this study we aimed to investigate loss of heterozygosity (LOH) as well as the frequency and patterns of the mutations in the PTEN, AKT and TP53 genes in OL and tongue squamous cell carcinoma (TSCC) samples of smokers and non-smokers patients. Tissue specimens were obtained from 73 patients: 35 cases of TSCC and 38 cases of high grade OL occurring in the lateral border of the tongue, and PTEN, AKT e TP53 gene mutations were investigated through Fluorescence In Situ Hybridization and genotyping. Differences between the genetic changes studied in the TP53, PTEN and AKT genes in smoking and non-smoking patients were detected. Changes in the TP53 gene did not occur significantly in the OL stage in either smoking or non-smoking patients, whereas changes in the PTEN gene were observed in both OL and OSCC, with a statistically significant difference between smokers and non-smokers. Furthermore, changes in the AKT gene did not occur with high frequency in either OL or carcinomas, regardless of smoking status, suggesting that disruptions in the critical PI3K pathway are primarily due to genetic changes in PTEN rather than in the AKT gene.

Solitary Fibrous Tumor (SFT) is a rare mesenchymal neoplasm, account approximately 3% of mesenchymal tumors in the oral cavity. We present the case of a 65-year-old female patient with a painless swelling in the left upper lip. Clinical examination revealed a firm, smooth-surfaced submucosal lesion without ulceration, non-tender on palpation, and exhibiting a slightly yellowish hue. Computed tomography demonstrated a well-defined, isodense mass measuring 25 mm in diameter, with no evidence of bone invasion. The lesion was surgically excised, and histopathological analysis confirmed the diagnosis of SFT, supported by positive immunohistochemical staining for CD34 and STAT6. The tumor was classified as low risk for metastasis, and the patient demonstrated favorable postoperative recovery. The patient remains under follow-up with the medical team and has been recurrence-free for 07 months. This case underscores the rarity of oral cavity SFT and emphasizes the importance of comprehensive differential diagnosis to guide effective management and reduce recurrence risk.

Understanding the early molecular events driving oral carcinogenesis is vital for diagnosing oral squamous cell carcinoma (OSCC) promptly. While metabolic differences between oral leukoplakia (OLK), OSCC, and healthy oral mucosa have been reported, the metabolic changes distinguishing malignant transformed OLKs (MT-OLK) from non-transformed OLKs (NT-OLK) remain unexplored. Here, we examine the metabolomic profiles of 5 cases of MT-OLK and 15 of NT-OLK to identify key predictive molecules using untargeted high-performance liquid chromatography-mass spectrometry. The potentially discriminant compounds were highlighted through a robust statistical analysis workflow, and the dysregulated metabolic pathways were illustrated by enrichment analysis. Seventeen molecular features, primarily lipids—including phospholipids, oxidised lipids, cholesteryl esters, and fatty acids—were identified as discriminants between MT-OLK and NT-OLK across statistical and bioinformatic approaches. Pathway enrichment analysis revealed alterations in lipid metabolism, particularly fatty acid synthesis and degradation, steroid hormone biosynthesis, and glycerophospholipid metabolism. Predictive models showed high accuracy (AUC = 0.88) in distinguishing the two groups. This study suggests that metabolomics has the potential to differentiate between MT-OLK and NT-OLK by identifying candidate biomarkers that may contribute to the understanding of malignant transformation. Validation in larger cohorts is warranted to translate these findings into clinical practice.

Background: Rhabdomyosarcoma (RMS), a rare malignant tumor, frequently affects pediatric patients, with 35%–40% occurring in the head and neck. This study analyzes the clinicopathologic profile of pediatric head and neck rhabdomyosarcomas from Brazil, Guatemala, Mexico, and South Africa.Methods: We reviewed 44 cases from 10 Oral and Maxillofacial Pathology services, conducting immunohistochemical analyses of desmin, myogenin, Myo‐D1, and Ki67, with quantification via QuPath software. Cases with ≥ 50% myogenin expression were tested for fusion status using AP2β, NOS‐1, and HMGA2. Statistical analyses included the Kruskal–Wallis test for age and marker expression comparisons, Fisher's exact test for categorical variables, Spearman's rank correlation for marker relationships, and multinomial logistic regression to assess fusion status likelihood.Results: Cases were predominantly from Brazil (40.9%), followed by South Africa (27.3%), Guatemala (22.7%), and Mexico (9.1%). Two‐thirds of patients were diagnosed in their first decade with no gender predilection. Nonparameningeal sites (45.5%) were more affected than parameningeal (40.9%) and orbital sites. Microscopically, embryonal RMS (77.3%) was most common, followed by alveolar (18.2%) and spindle cell (2.3%) tumors. Immunohistochemistry revealed positivity for myogenic markers, with significant differences in myogenin expression between embryonal and alveolar RMS variants (p < 0.05). Fusion status prediction identified two potential fusion‐positive alveolar RMS cases, while all embryonal RMS and one alveolar RMS case appeared fusion‐negative. Significant correlation with positive fusion status was found only between AP2β and NOS1 (p < 0.05).Conclusion: Although there are slight clinical‐demographic variations among pediatric head and neck rhabdomyosarcomas in these regions, identifying fusion status through immunohistochemistry remains a diagnostic challenge.