Subgemmal neurogenous plaque: a series of six cases and a literature overview.

The study aims to describe six subgemmal neurogenous plaque (SNP) cases and compile the previously available data on SNP. Searches on PubMed, Web of Science, Embase, Scopus, and a two-step study selection were performed to compile data from case reports/series of SNP published in English literature. Our six patients (range 29-63 years) had SNP in the posterior lateral border of the tongue. Four of them were associated with lymphoepithelial cysts. A total of 15 studies, comprising 116 patients, were included in this overview. There was a slight predilection for female patients (56.0%) in the 5th (22.4%) and the 7th (23.9%) decades. The lateral border of the tongue (66.4%) was the most common anatomical location. The major manifestation was nodule/papule. Histologically, the presence of taste buds (n = 40/ 34.5%), superficial neural plexus (n = 32/ 27.6%), deep nerve fascicles (n = 32/ 27.6%), ganglion cells (n = 41/ 35.3%), and lymphoid tissue (n = 22/ 19.0%) was mainly reported. Surgical removal was the primary approach, with a low recurrence rate. Although largely unknown, SNP is a regular and likely frequent structure located in the tongue. The findings emphasize the importance of describing clinicopathological patterns of SNP as a differential diagnosis of neural lesions that affect the tongue.

Clinical diagnostic approach for oral lymphomas: a multi-institutional, observational study based on 107 cases.

OBJECTIVE: To evaluate oral lymphomas' clinical manifestations and investigate whether clinical features are associated with lymphoma subtypes. STUDY DESIGN: Oral lymphomas with at least 1 representative clinical image were evaluated. They were classified according to their microscopic grade (high vs low), predominant cell size (small vs medium/large), and cellular lineage (B cell vs T cell). Clinical images were described according to tumor location, number, swelling, ulcer, necrosis, telangiectasia, predominant color, and lobulation. Lymphomas affecting the palate were compared with salivary gland tumors (SGTs) affecting this location. RESULTS: Data from 107 cases were included. High-grade subtypes (80.4%), with medium/large-sized cells (52.3%), and diagnosed as diffuse large B cell lymphomas (29%) predominated. High-grade lymphomas often presented as painful, ulcerative, and osteolytic diseases (P < .05). Tumors predominantly composed of medium/large-sized cells were associated with painful lesions, ulcerated, with necrosis and bone destruction (P < .05). When only palate tumors were considered, multiple and bilateral lesions, the presence of pain, ulceration, and necrosis were significantly more associated with a diagnosis of lymphoma than SGT (P < .001). CONCLUSION: High-grade oral lymphomas are more associated with destructive presentation than low-grade subtypes, and bilateral lesions in the palate are more associated with a lymphoma diagnosis than SGT.

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.

Interrogation of TERT promoter hotspot mutations in ameloblastoma and ameloblastic carcinoma.

BACKGROUND: TERT promoter mutations increase telomerase activity, conferring cell immortality. The coexistence of TERT promoter mutations with BRAFV600E is associated with aggressiveness. Ameloblastoma and ameloblastic carcinoma are infiltrative neoplasms that harbor BRAFV600E; however, it remains unknown if these odontogenic tumors also show TERT promoter mutations. METHODS: Genomic DNA of paraffin-embedded ameloblastomas (n = 6) and ameloblastic carcinomas (n = 3) were Sanger-sequenced to assess the hotspot TERT promoter mutations C228T and C250T. BRAFV600E status was screened by TaqMan allele-specific quantitative polymerase chain reaction. RESULTS: None of the samples harbored TERT promoter mutations. The BRAFV600E mutation was positive in 3 of 6 of ameloblastomas and in 1 of 3 of ameloblastic carcinomas. CONCLUSION: The absence of TERT promoter mutation in the samples indicates that this molecular event is not relevant to the tumors' pathogenesis. Further studies are necessary to explore undefined genetic or epigenetic mechanisms related to TERT-upregulation in ameloblastoma, and the telomerase activity in ameloblastic carcinoma.

Fine-needle aspiration cytology for the diagnosis of plasma cell neoplasms in the head and neck region: A systematic analysis of the literature.

BACKGROUND: Cytopathologic analysis is feasible and provides detailed morphological characterisation of head and neck lesions. AIMS: To integrate the available data published on fine-needle aspiration cytology (FNAC) used for the diagnosis of plasma cell neoplasms (PCN) of the head and neck region. MATERIALS AND METHODS: Searches on PubMed, Web of Science, Embase, and Scopus were performed to compile data from case reports/case series published in English. The Joanna Briggs Institute tool was used for the critical appraisal of studies. RESULTS: A total of 82 studies comprising 102 patients were included in this review. There was a predilection for men (68.6%) (male/female ratio: 2.1:1). Individuals in their 50s (29.4%), 60s (22.5%), and 70s (22.5%) were more often affected. The thyroid gland (26.2%) was the main anatomical location, followed by scalp (15.5%), neck/cervical region (15.5%), jaws (13.6%), and major salivary glands (13.6%). For FNAC analysis, a smear was employed in 41 (40.6%) cases and a cell block was used in four (3.9%). In 56 (55.4%) reports, no cytological methods were available. Morphologically, 34 (56.7%) cases had a diagnosis of PCN with agreement between cytopathology and histopathology. The rate of wrong diagnoses when using cytology was 27.5%. Immunophenotyping was performed in 49 (48%) of the cases. The 69-month disease-free survival rate was 60.2%, while the 27-month overall survival rate was 64.1%. CONCLUSION: This study reinforces that FNAC can be an ancillary tool in the first step towards the diagnosis of PCN of the head and neck region, especially when applying a cell block for cytological analysis.

Angina bullosa haemorrhagica: A 14-year multi-institutional retrospective study from Brazil and literature review

Background: Angina bullosa haemorrhagica (ABH) is characterized by the recurrent appearance of blood blisters on the oral mucosa, mainly in adults' soft palate. In general, the blisters rupture spontaneously, lacking the necessity for biopsy. We report the clinical features of 23 ABH cases, emphasizing the clinical behavior and the management of these conditions. Material and Methods: A retrospective descriptive cross-sectional study was performed. A total of 12,727 clinical records of oral and maxillofacial lesions from four dental services in Brazil were analyzed. Clinical data were collected from the clinical records and evaluated. Results: The series comprised 12 males (52.2%) and 11 females (47.8%), with a mean age of 56.8 ± 14.6 years (ranging: 24-82 years) and a 1.1:1 male-to-female ratio. Most of the lesions affected the soft palate (n = 15, 65.2%). Clinically, the lesions presented mainly as an asymptomatic (n = 17, 73.9%) blood-filled blister that ruptured after a few minutes or hours, leaving an erosion. The masticatory trauma was the most frequent triggering event. No patient had coagulation disorders. A biopsy was performed in only four cases (17.4%). Treatment was symptomatic with a favorable outcome. Conclusions: ABH is still poorly documented in the literature, and its etiology remains uncertain. ABH mainly affects the soft palate of elderly adults and has a favorable evolution in a few days. The therapeutic approach is often focused only on the relief of symptoms. However, it can share some clinical features with more serious diseases. Therefore, clinicians must recognize these lesions to avoid misdiagnosis.(AU)

Oral Juvenile Xanthogranuloma: A Clinicopathological, Immunohistochemical and BRAF V600E Study of Five New Cases, with Literature Review.

Juvenile xanthogranuloma (JXG) is the most common form of non-Langerhans cell histiocytosis and oral mucosal involvement is exceedingly rare. Histiocytic disorders harbor activating mutations in MAPK pathway, including the report of BRAF V600E in JXG of extracutaneous site. However, no information is available for oral JXG. Herein, the clinicopathological and immunohistochemical features of five new oral JXG were evaluated in conjunction with literature review. Also, we assessed the BRAF V600E in oral samples. Five oral JXG were retrieved from pathology archives. Morphological and immunohistochemical analyses were performed. The BRAF V600E status was determined with TaqMan allele-specific qPCR. The series comprised of three female and two male patients, most of them adults, with a median age of 39 years (range 13-68 years). Clinically, the lesions appeared as asymptomatic solitary nodules, measuring until 2.5 cm, with more incident to the buccal mucosa. Morphologically, most of the cases presented classical histological features of JXG, with histiocytic cells consistent with the non-Langerhans cell immunophenotype. BRAF V600E was not detected in the cases tested. This is the first and largest published series of oral JXG affecting adults and a Brazilian population. The molecular pathogenesis of oral JXG remains unknown. Clinicians and pathologists must recognize JXG to avoid misdiagnoses with oral benign or malignant lesions.

Fat-free pleomorphic lipoma of the buccal mucosa: An immunohistochemical study and literature review.

Pleomorphic lipomas are extremely rare in the oral cavity. Due to the significant overlap of morphological findings with several benign and malignant soft tissue tumors, especially in the absence of adipocytes, the diagnosis is challenging. We reported the clinicopathological and immunohistochemical features of an uncommon case of a fat-free variant of pleomorphic lipoma in a 48-year-old female presenting clinically as a painless nodule on the buccal mucosa. Microscopically, the lesion showed atypical spindle cells, numerous floret-like giant multinucleated cells, and abundant ropey collagen fibers bundles. Immunohistochemistry showed strong positivity for vimentin and CD34. Mast cell tryptase highlighted numerous mast cells distributed throughout all tumor stroma. S-100 protein, pan-cytokeratin, desmin, α-SMA, EMA, CD68, STAT6, Bcl-2, MDM2, and CDK4 were negative. Conservative surgical excision was carried out, and no recurrence was observed after 13 months of follow-up. Careful histopathological and immunohistochemistry analysis of these lesions is recommended to ensure the correct diagnosis and provide adequate management through a conservative surgical approach. To the best of our knowledge, this is the second case of fat-free pleomorphic lipoma in the oral cavity.

Aggressive Intraosseous Myofibroma of the Maxilla: Report of a Rare Case and Literature Review.

Myofibroma (MF) is a benign mesenchymal myofibroblast-derived tumor, which occurs most frequently in children, and rarely affects the maxilla. We reported a case of an aggressive intraosseous lesion found in the maxilla of a 9-year-old female child. Intraorally, the swelling extended from tooth 12 to 16, causing displacement of teeth 13, 14, and 15. Computed tomography revealed a large osteolytic lesion causing thinning and cortical erosion. Microscopically, the lesion showed a proliferation of spindle-shaped cells, with elongated nuclei and eosinophilic cytoplasm, arranged in interlaced fascicles. The immunohistochemical analysis revealed cytoplasmic positivity for α-SMA and HHF-35, and negativity for desmin, laminin, S-100, ß-catenin, and CD34. Ki-67 was positive in 8% of tumor cells. The diagnosis was MF. Herein, we describe an additional case of central MF arising in the maxilla, including clinical, imaging, microscopical, and immunohistochemical features, as well as a review of the literature.

Whole-exome sequencing reveals novel vacuolar ATPase genes' variants and variants in genes involved in lysosomal biology and autophagosomal formation in oral granular cell tumors.

BACKGROUND: Granular cell tumors (GCTs) are rare neuroectodermal soft tissue neoplasms that mainly affect the skin of the upper limbs and trunks and the oral cavity. GCTs are derived from Schwann cells and, ultrastructurally, their intracytoplasmic granules are considered autophagosomes or autophagolysosomes and are consistent with myelin accumulation. METHODS: In this study, a convenience set of 22 formalin-fixed, paraffin-embedded samples of oral GCTs, all but one sample located at the tongue, was screened for mutations by whole-exome (WES) or targeted sequencing. RESULTS: WES revealed two novel variants in genes of the vacuolar ATPase (V-ATPase) complex: ATP6AP1 frameshift c.746_749del, leading to p.P249Hfs*4, and ATP6V1A non-synonymous c.G868A, leading to p.D290N. Each of these mutations occurred in one case. With regard to the samples that were wild type for these V-ATPase variants, at least two samples presented variants in genes that are part of endosomal/lysosomal/autophagosomal networks including ABCA8, ABCC6, AGAP3, ATG9A, CTSB, DNAJC13, GALC, NPC1, SLC15A3, SLC31A2, and TMEM104. CONCLUSION: Although the mechanisms involved in oral GCT initiation and progression remain unclear, our results suggest that oral GCTs have V-ATPase variants similarly to GCTs from other tissues/organs, and additionally show variants in lysosomes/endosomes/autophagosomal genes.

Sialolipomas of minor salivary glands: A multi-institutional study and literature review.

BACKGROUND: Sialolipoma is a rare histological variant of lipoma commonly misdiagnosed and composed of a proliferation of mature adipocytes with secondary entrapment of normal salivary gland tissue. The purpose of the present study is to report the clinicopathologic and immunohistochemical features of 10 new cases of sialolipomas in conjunction with a review of the literature. METHODS: A retrospective descriptive cross-sectional study was performed. A total of 54,190 biopsy records of oral and maxillofacial lesions from four oral and maxillofacial pathology services in Brazil were analysed. All cases of lipomas were reviewed, and clinical, demographic and histopathological data were collected of all cases compatible with sialolipomas. In addition, immunohistochemistry stains (AE1/AE3, CK7, 34ßE12, S-100, HHF35, α-SMA and Ki-67) and a literature review based on a search of three electronic databases (PubMed, Web of Science and Scopus) were performed. RESULTS: Among all lipomas reviewed, there were 10 cases of sialolipomas. The series comprised of 7 females (70.0%) and 3 males (30.0%), with a mean age of 46.1 ± 21.5 years (range: 11-71 years) and a 2.3:1 female-to-male ratio. The lower lip (n = 3, 30.0%) and tongue (n = 2, 20.0%) were the most common locations, presenting clinically as a nodule of slow growth and normal colour. Conservative surgical excision was the treatment in all cases. No recurrence was observed. CONCLUSION: Sialolipomas are a rare histological variant of lipoma, affecting the salivary glands, mainly in the parotid gland and palate of female adults. Pathologists must recognise sialolipomas to avoid misdiagnoses with other lipomatous tumours that can affect salivary glands.

Genotoxic and cytotoxic effects of mobile phone use on the oral epithelium: a systematic review with meta-analysis.

The use of mobile phones is based on radiofrequency (RF) waves, and the devices act as transmitters and receivers of non-ionizing energy. The micronucleus test was developed to identify increases in the occurrence of mutations in cells exposed to various agents. This systematic review with meta-analysis adhered to the following protocol: defining the objective, outlining the search method (PICO model), conducting the search, identifying literature, selecting articles, and extracting data. The study aimed to answer the following research question: Does non-ionizing radiation emitted by mobile phones have genotoxic and/or cytotoxic effects on the oral epithelium? The search for evidence published 2009-2019 was conducted in the MEDLINE, PubMed, Scopus, LILACS, Google Scholar, PROSPERO, and Cochrane Library databases. The following inclusion criteria were defined: investigations of effects on the oral mucosa related to RF; investigations of cytotoxic and/or genotoxic effects; investigations involving humans; and investigations using cells exfoliated from the oral epithelium. Investigations related to the parotid gland were excluded. The search strategy found 464 articles; after application of the eligibility criteria, 358 abstracts were analyzed and 351 abstracts excluded. After 7 full texts were reviewed, 1 study was excluded. The 6 included studies were classified as level 5 quality of evidence (observational studies). The meta-analysis included 2 studies that compared the frequency of micronuclei on the side exposed to RF electromagnetic fields (RF-EMFs) to that on the unexposed side. The studies evaluated presented a low degree of evidence, but the meta- analysis indicated that no genotoxic effects are associated with mobile phone use. However, observations of other nuclear abnormalities in some studies suggest the occurrence of cytotoxic effects caused by exposure to the RF-EMFs emitted by mobile phones. More studies are necessary to prove or refute this association.

Targeted Next-Generation Sequencing and Allele-Specific Quantitative PCR of Laser Capture Microdissected Samples Uncover Molecular Differences in Mixed Odontogenic Tumors.

The molecular pathogenesis of mixed odontogenic tumors has not been established, and understanding their genetic basis could refine their classification and help define molecular markers for diagnostic purposes. Potentially pathogenic mutations in the component tissues of 28 cases of mixed odontogenic tumors were assessed. Laser capture microdissected tissue from 10 ameloblastic fibromas (AF), 4 ameloblastic fibrodentinomas (AFD), 6 ameloblastic fibro-odontomas (AFO), 3 ameloblastic fibrosarcomas (AFS), and 5 odontomas (OD) were screened by next-generation sequencing and results confirmed by TaqMan allele-specific quantitative PCR. BRAF p.V600E mutation in the mesenchymal component was shown in 4 of 10 AF (40%), 2 of 4 AFD (50%), 2 of 6 AFO (33%), and 2 of 3 AFS (67%), whereas all 5 OD were wild type for BRAF p.V600E. Mutation in the epithelial component was only observed in one AF and one AFO. One AFS contained an area of benign AF, and the mesenchymal component of both (AFS and AF) contained BRAF p.V600E, supporting the concept of malignant progression from a benign AF precursor. KDR, TP53, KIT, and PIK3CA single-nucleotide polymorphisms are reported. In conclusion, AF, AFD, AFO, and AFS show BRAF p.V600E in their mesenchymal component, unlike OD, which are BRAF wild type, suggesting that at least a subset of AF, AFD, and AFO are molecularly distinct from OD, and may represent distinct entities and be neoplastic.

Odontogenic myxomas lack PDGFRB mutations reported in myofibromas.

BACKGROUND: The molecular pathogenesis of odontogenic myxoma has not been established yet. Considering that odontogenic myxoma may show myofibroblastic differentiation and myxoid areas can be observed in intra-osseous myofibromas, we tested the hypothesis whether both tumors share a common molecular profile. As recent studies have reported PDGFRB recurrent driver mutations in myofibroma, we evaluated PDGFRB mutations in odontogenic myxomas. METHODS: A convenience sample of 15 odontogenic myxomas cases was selected. We direct sequenced PDGFRB exons 12 and 14, where p.R561C (c.1681C>T) and p.N666K (c.1998C>G) hotspot mutations have been reported among others in single and/or multiple myofibromas. RESULTS: All 15 odontogenic myxoma samples were successfully sequenced, and all 15 had wild-type sequences for the PDGFRB mutations investigated. CONCLUSION: Our findings suggest that PDGFRB mutations do not play a role in odontogenic myxoma pathogenesis, which might be helpful in the differential diagnosis of challenging cases.

CTNNB1 and APC mutations in odontogenic carcinoma with dentinoid.

The purpose of the present study is to report 2 cases of odontogenic carcinoma with dentinoid, a rare low-grade odontogenic carcinoma associated with facial deformity and bone loss, and to investigate the presence of pathogenic mutations in these samples. By using a next-generation sequencing approach, we sequenced a panel of 50 oncogenes and tumor suppressor genes commonly mutated in human cancer. Microscopic features of both cases revealed solid areas of malignant odontogenic tumor with a large amount of dentinoid material. We identified pathogenic mutations in the genes CTNNB1 and APC, both of which are part of the Wnt-signaling pathway. Consistent with Wnt-signaling activation, both tumors showed strong ß-catenin accumulation in the cytoplasm and in the nuclei. The molecular profile of odontogenic carcinoma with dentinoid may help in its diagnosis, as well as in the identification of potential molecular targets for therapy in the future.

Assessing pathogenic mutations in dental follicles as an attempt to identify early events in odontogenic tumours tumourigenesis.

OBJECTIVE: Driver oncogenic mutations have been reported in several benign neoplasms. While ameloblastomas show BRAF p.V600E mutations, adenomatoid odontogenic tumours harbour either KRAS p.G12R or p.G12 V. The lack of understanding of the core molecular changes involved in tumour initiation and progression represents a critical barrier to developing new strategies for cancer detection and prevention. Considering the fact that ameloblastoma and adenomatoid odontogenic tumours can originate from dental follicles, we hypothesized that the BRAF and KRAS mutations might be early events in odontogenic tumours tumourigenesis. We aimed to assess BRAF and KRAS mutations in dental follicles associated with asymptomatic impacted teeth. DESIGN: Forty-eight dental follicles containing odontogenic epithelial remnants were included in the study. As ameloblastomas most often occur in the posterior mandible and adenomatoid odontogenic tumours have a predilection for the anterior jaws, we assessed by allele-specific qPCR the presence of BRAF p.V600E in 32 dental follicles associated with impacted 3rd mandibular molar teeth and KRAS p.G12 V and KRAS p.G12R mutations in 16 dental follicle specimens obtained from around impacted anterior teeth. Sanger sequencing was used as an additional method. RESULTS: None of the dental follicle cases tested positive for the mutations. CONCLUSION: In conclusion, we tried to detect the early genetic events associated with odontogenic tumours development in dental follicles, but we were unable to showcase that BRAF p.V600E and KRAS p.G12R or p.G12 V mutations are the early genetic events associated with odontogenic tumours development.

Solitary fibrous tumour of the oral cavity: An update.

BACKGROUND: Solitary fibrous tumour is an unusual neoplasm of the oral cavity that is sometimes not clinically distinguishable from other lesions. The purpose of the present study was to review the clinical, microscopic and molecular aspects of malignant and benign solitary fibrous tumour of the oral cavity currently available in literature. METHODS: For our review, an electronic search was performed using PubMed, Scopus, Ovid/MedLine, Web of science and ProQuest Dissertations and Theses Global database. RESULTS: A total of 74 publications reporting 150 cases were included. Oral solitary fibrous tumours are most frequently described as submucosal, well-circumscribed, asymptomatic nodule, more prevalent in females in their fourth to fifth decades of life. Buccal mucosa is the most commonly affected site by the benign tumour variant, whereas the tongue is the most common location affected by the malignant form of the neoplasm. Most of the lesions were treated by conservative surgery. One recurrent malignant tumour and one metastasis are reported. CONCLUSION: Asymptomatic normal-coloured submucosal nodules located in the buccal mucosa and tongue in adult patients are suggestive of oral solitary fibrous tumour, but only a careful microscopic examination can differentiate benign from malignant variants and the use of immunohistochemistry (CD34, Bcl-2, CD99 and STAT6), and cytogenetic studies (NAB2-STAT6) contribute significantly to confirm the diagnosis of solitary fibrous tumour in difficult cases.