Comprehensive Genomic Analysis of Cemento-Ossifying Fibroma.

Cemento-ossifying fibroma (COF) of the jaws is currently classified as a benign mesenchymal odontogenic tumor, and only targeted approaches have been used to assess its genetic alterations. A minimal proportion of COFs harbor CDC73 somatic mutations, and copy number alterations (CNAs) involving chromosomes 7 and 12 have recently been reported in a small proportion of cases. However, the genetic background of COFs remains obscure. We used a combination of whole-exome sequencing and RNA sequencing to assess somatic mutations, fusion transcripts, and CNAs in a cohort of 12 freshly collected COFs. No recurrent fusions have been identified among the 5 cases successfully analyzed by RNA sequencing, with in-frame fusions being detected in 2 cases (MARS1::GOLT1B and PARG::BMS1 in one case and NCLN::FZR1 and NFIC::SAMD1 in the other case) and no candidate fusions identified for the remaining 3 cases. No recurrent pathogenic mutations were detected in the 11 cases that had undergone whole-exome sequencing. A KRAS p.L19F missense variant was detected in one case, and 2 CDC73 deletions were detected in another case. The other variants were of uncertain significance and included variants in PC, ACTB, DOK6, HACE1, and COL1A2 and previously unreported variants in PTPN14, ATP5F1C, APOBEC1, HDAC5, ATF7IP, PARP2, and ACTR3B. The affected genes do not clearly converge on any signaling pathway. CNAs were detected in 5/11 cases (45%), with copy gains involving chromosome 12 occurring in 3/11 cases (27%). In conclusion, no recurrent fusions or pathogenic variants have been detected in the present COF cohort, with copy gains involving chromosome 12 occurring in 27% of cases.

A conservative approach for unicystic ameloblastoma: Retrospective clinic-pathologic analysis of 12 cases.

BACKGROUND: Unicystic ameloblastoma is an encapsulated odontogenic neoplasm with a single cyst cavity. The conservative or aggressive surgical approaches used to treat the tumor directly affect recurrence rates. However, there is a lack of a standard protocol that can guide its management. STUDY DESIGN: We retrospectively reviewed the clinicopathological findings and therapeutical procedures of 12 unicystic ameloblastoma cases treated by the same surgeon during the past 20 years. METHODS: All cases of unicystic ameloblastoma diagnosed by biopsy and treated by the same surgeon between 2002 and 2022 were reviewed. Eligibility criteria were patients with completely filled-out charts containing the follow-up period and confirmation of the diagnoses based on the microscopic findings of the whole excised specimens. Data collected were categorized into clinical, radiographic, histological, surgical, and recurrence aspects. RESULTS: There was a female predilection (2:1), and ages ranged between 18 and 61 years (mean: 27.25, ±12.45). Almost all (92%) affected the posterior mandible. Radiographically, the mean length of the lesions was 46.14 mm ± 14.28 mm which 92% were unilocular and 8.3% multilocular. Root resorption (n = 7, 58%), tooth displacement (n = 9, 75%), and cortical perforation (n = 5, 42%) were also observed. The mural histological subtype corresponded to 9 (75%) of the cases. The same conservative protocol was performed in all cases. The follow-up period ranged between 12 and 240 months (~62 ± 65) and recurrence occurred in only one patient (8%). CONCLUSION: Our findings suggest a conservative approach should be the first option for unicystic ameloblastoma treatment, even for those with mural proliferation.

Cheilitis glandularis: case report and systematic literature review.

Cheilitis glandularis (CG) is a rare inflammatory disease of unknown etiology that affects the minor salivary glands predominantly in the lower lip. In this article, we report the case of an 18-year-old black woman who presented with a deep suppurative type of CG in both lips. In addition, we performed a systematic literature review in five databases (PubMed, Scopus, Web of Science, Ovid, and Embase) to identify CG case reports or case series. A total of 360 references were retrieved in the electronic databases. Thirty-four articles met the inclusion criteria, and six were retrieved through manual search, totaling 40 articles included in the systematic review. Thirty-nine (68.4%) cases occurred in male individuals and 18 (31.6%) in female individuals. The mean age of affected individuals was 40.9 years. Different clinical manifestations ranging from no symptoms to discomfort, pain, swelling, erythema, eversion of the lip, dilated ductal openings, ulcers, and crust have been reported. Among the included CG cases, 41 affected exclusively the lower lip (71.9%). In four cases, the CG only affected the upper lip (7.0%). In 12 cases, the lesion affected both the lower and upper lips (21.1%). Different treatment modalities were adopted in the management of CG. Although the surgical treatment was indicated (42.1%), the conservative treatment with topical medications, as in the present case, resulted in resolution in 21.0% of cases.

A new TRPV4 mutation in a case of multiple central giant cell granulomas of the jaws.

Sporadic central giant cell granulomas of the jaws (GCGJ) are often solitary lesions, characterized by KRAS, FGFR1, and TRPV4 somatic mutations. Multifocal lesions may occur and are associated with hyperparathyroidism or underlying syndromes such as cherubism, which is marked by SH3BP2 mutations, and RASopathies, which are caused by mutations in the FGFR-RAS-RAF-MEK-ERK signaling cascade. The diagnosis of multiple GCGJ can be challenging. The present case reports a 14-year-old boy with multiple central GCGJ and no obvious syndromic trait. Sanger sequencing-based analysis revealed wild-type sequences for SH3BP2 (exon 9), KRAS (exons 2-4), and FGFR1 (exons 9 and 10) genes. A rare TRPV4 somatic mutation (p.Val708Met) was detected in the lesion on the right side of the mandible, whereas the other tumor and the normal oral mucosa revealed wild-type TRPV4 sequences. This report expands the spectrum of TRPV4 somatic mutations in central GCGJ.

Unicystic adenoid ameloblastoma: A new variant?

Adenoid ameloblastoma with dentinoid is an uncommon benign odontogenic neoplasm, and its unicystic variant seems to be even rarer. A 34-year-old man was referred for evaluation of an asymptomatic swelling in the posterior maxilla. Intraoral examination showed an expansive lesion, soft to palpation, covered by a normal color mucosa. Cone beam computed tomography revealed a well-defined unilocular hypodense tumor involving the left maxillary sinus. Histopathological examination of the surgically excised specimen showed a cystic tumor lined by an ameloblastic-like epithelium containing columnar basal cells with hyperchromatic and polarized nuclei. In some areas of the capsule, the tumor showed mural infiltration by sheets of cells containing central whirling structures. Dentinoid material was also observed in association with ameloblastic-like cells. The tumor was BRAF and KRAS wild-type. Collectively, these findings were consistent with the diagnosis of a unicystic variant of adenoid ameloblastoma with dentinoid.

Unveiling metabolic changes in marsupialized odontogenic keratocyst: A pilot study.

OBJECTIVE: We aimed to assess which metabolic pathways would be implicated in the phenotypic changes of the epithelial lining of odontogenic keratocyst after marsupialization, comparing pre- and post-marsupialized lesions with adjacent oral mucosa. MATERIALS AND METHODS: Eighteen formalin-fixed and paraffin-embedded tissues from six subjects were divided into three paired groups: odontogenic keratocyst pre- (n = 6) and post-marsupialization (n = 6), and adjacent oral mucosa (n = 6). The metabolic pathways found in these groups were obtained by high-performance liquid chromatography-mass spectrometry-based untargeted metabolomics performed. RESULTS: Through putative metabolite annotation followed by pathway enrichment and predictive analysis with automated algorithms (Mummichog and Gene Set Enrichment Analysis), we found differences in many cellular processes that may be involved in inflammation, oxidative stress response, keratinocyte-basal membrane attachment, differentiation, and proliferation functions, all relevant to odontogenic keratocyst pathobiology and the phenotype acquired after marsupialization. CONCLUSION: Our study was able to identify several metabolic pathways potentially involved in the metaplastic changes induced by marsupialization of odontogenic keratocysts. An improved comprehension of this process could pave the way for the development of targeted therapies.

BRAF p.V600E status in epithelial areas of ameloblastoma with different histological aspects: Implications to the clinical practice.

BACKGROUND: BRAF p.V600E is reported in up to 80% of ameloblastomas. Despite the high frequency, the presence of this mutation in different histopathological areas of the tumour has not been investigated. This information has an important role in the use of BRAF p.V600E assessment as an auxiliary tool in the differential diagnosis between unicystic ameloblastoma and other odontogenic cystic lesions, especially when only incisional biopsies are available. Therefore, the purpose of the present study was to investigate BRAF p.V600E heterogeneity in unicystic ameloblastoma. METHODS: Five cases of ameloblastoma and two dentigerous cysts were analysed. The regions exhibiting different microscopic characteristics were selected from each ameloblastoma case and manually dissected. TaqMan allele-specific qPCR or Sanger sequencing was performed to determine BRAF p.V600E status. RESULTS: We screened the mutation in a small cohort of UA and no molecular heterogeneity was found. Four cases of ameloblastoma (80%) exhibited BRAF p.V600E in all different areas evaluated. One case did not harbour the mutation in any microscopic region analysed. The BRAF mutation was absent in the dentigerous cysts. CONCLUSION: Ameloblastomas appear to exhibit a homogeneous profile regarding the BRAF p.V600E no matter what histological feature is observed under light microscopy, suggesting that this molecular test may contribute to establish the correct diagnosis in cases microscopically resembling other odontogenic lesions.

Multiple adenomatoid odontogenic tumors in a patient with Schimmelpenning syndrome.

Schimmelpenning syndrome (SS) is a congenital neurocutaneous disorder characterized by the presence of linear nevus sebaceous, ophthalmic, neurologic, skeletal, urologic, and cardiovascular alterations. Oral manifestations related to SS mainly include dental defects, papillary lesions in the oral mucosa, giant cell lesions of the jaws, and odontogenic tumors. Here, we report the first case of multiple adenomatoid odontogenic tumor observed in a patient with SS.

MicroRNA profiling reveals dysregulated microRNAs and their target gene regulatory networks in cemento-ossifying fibroma.

BACKGROUND: Cemento-ossifying fibroma (COF) is a benign fibro-osseous neoplasm of uncertain pathogenesis, and its treatment results in morbidity. MicroRNAs (miRNA) are small non-coding RNAs that regulate gene expression and may represent therapeutic targets. The purpose of the study was to generate a comprehensive miRNA profile of COF compared to normal bone. Additionally, the most relevant pathways and target genes of differentially expressed miRNA were investigated by in silico analysis. METHODS: Nine COF and ten normal bone samples were included in the study. miRNA profiling was carried out by using TaqMan® OpenArray® Human microRNA panel containing 754 validated human miRNAs. We identified the most relevant miRNAs target genes through the leader gene approach, using STRING and Cytoscape software. Pathways enrichment analysis was performed using DIANA-miRPath. RESULTS: Eleven miRNAs were downregulated (hsa-miR-95-3p, hsa-miR-141-3p, hsa-miR-205-5p, hsa-miR-223-3p, hsa-miR-31-5p, hsa-miR-944, hsa-miR-200b-3p, hsa-miR-135b-5p, hsa-miR-31-3p, hsa-miR-223-5p and hsa-miR-200c-3p), and five were upregulated (hsa-miR-181a-5p, hsa-miR-181c-5p, hsa-miR-149-5p, hsa-miR-138-5p and hsa-miR-199a-3p) in COF compared to normal bone. Eighteen common target genes were predicted, and the leader genes approach identified the following genes involved in human COF: EZH2, XIAP, MET and TGFBR1. According to the biology of bone and COF, the most relevant KEGG pathways revealed by enrichment analysis were proteoglycans in cancer, miRNAs in cancer, pathways in cancer, p53-, PI3K-Akt-, FoxO- and TGF-beta signalling pathways, which were previously found to be differentially regulated in bone neoplasms, odontogenic tumours and osteogenesis. CONCLUSION: miRNA dysregulation occurs in COF, and EZH2, XIAP, MET and TGFBR1 are potential targets for functional analysis validation.

Pain control in third molar surgery / Control del dolor en cirugía de tercer molar

The sensation of pain at the surgical site may be increased and persist for long periods after the noxious stimulus has been removed. Post-operative pain from the extraction of impacted molar may cause serious discomfort to the patient resulting in considered moderate to severe in intensity. Analgesia for this surgical procedure is related to the use of nonsteroidal anti-inflammatory drugs, steroids, analgesics of central and peripheral actions used in combination or individually. The aim of this review is to show an update about the use and the physiological bases for indications of the analgesic therapy in third molar surgery.

La sensación de dolor en el sitio quirúrgico puede ser mayor y persistente por largos periodos de tiempo después de que el estímulo nocivo ha sido retirado. El dolor postoperatorio desde la extracción de un molar impactado puede causar molestias moderadas o severas en intensidad. La analgesia para estos procedimientos son relacionadas con el uso de fármacos antiinflamatorios no esteroidales, esteroides, analgésicos de acción central y periféricos utilizados en combinación o individualmente. El objetivo de esta revisión es mostrar una puesta al día en el uso y las bases fisiológicas para la indicación de terapia analgésica en cirugía de tercer molar.

Clinicopathologic features associated with recurrence of the odontogenic keratocyst: a cohort retrospective analysis.

OBJECTIVE: The aim of this study was to evaluate the influence of clinical, radiographic, surgical and histopathologic parameters in the recurrence of disease in a series of odontogenic keratocysts (OKCs). STUDY DESIGN: The sample comprised 24 sporadic OKC lesions from 24 patients. All patients had no previous treatment history and were treated by the same surgeon using a uniform treatment protocol (enucleation with peripheral ostectomy preceded or not preceded by decompression). RESULTS: Fourteen lesions (58.4%) were first submitted to decompression procedure. Eight patients (33%) developed recurrent lesions, with a mean follow-up time of 60.5 months (standard deviation [SD] = 31.3) and a mean disease-free interval for recurrent lesions of 19 months (SD = 4.9). Recurrence was significantly associated with poor clinical response to decompression (P = .027), remaining tooth with radiographic evidence of insinuation of the lesion between the dental roots (P = .009), and the presence of budding of the basal cells layer together with epithelial islands in the fibrous capsule (P = .019). CONCLUSIONS: Clinical, radiographic and histopathologic parameters may affect the relapse rate of OKCs and should individually guide treatment choice.

BRAFV600E mutation in the diagnosis of unicystic ameloblastoma.

BACKGROUND: Unicystic ameloblastoma, an odontogenic neoplasm, presents clinical and radiographic similarities with dentigerous and radicular cysts, non-neoplastic lesions. It is not always possible to reach a final diagnosis with the incisional biopsy, leading to inappropriate treatment. The BRAFV600E activating mutation has been reported in a high proportion of ameloblastomas. The purpose of the study was to assess the utility of the detection of the BRAFV600E mutation in the differential diagnosis of unicystic ameloblastoma with dentigerous and radicular cysts. METHODS: Twenty-six archival samples were included, comprising eight unicystic ameloblastomas (UAs), nine dentigerous and nine radicular cysts. The mutation was assessed in all samples by anti-BRAFV600E (clone VE1) immunohistochemistry (IHC) and by TaqMan mutation detection qPCR assay. Sanger sequencing was further carried out when samples showed conflicting results in the IHC and qPCR. RESULTS: Although all UAs (8/8) showed positive uniform BRAFV600E staining along the epithelial lining length, the mutation was not confirmed by qPCR and Sanger sequencing in three samples. Positive staining for the BRAFV600E protein was observed in one dentigerous cyst, but it was not confirmed by the molecular methods. Furthermore, 2/9 dentigerous cysts and 2/9 radicular cysts showed non-specific immunostaining of the epithelium or plasma cells. None of the dentigerous or radicular cysts cases presented the BRAFV600E mutation in the qPCR assay. CONCLUSIONS: The BRAFV600E antibody (clone VE1) IHC may show non-specific staining, but molecular assays may be useful for the diagnosis of unicystic ameloblastoma, in conjunction with clinical, radiological and histopathological features.

Oral Spindle Cell Lipoma in a Rare Location: A Differential Diagnosis.

BACKGROUND: Spindle cell lipoma (SCL) is an uncommon and histologically distinct variant of lipoma. It usually occurs as a solitary, subcutaneous, and well-circumscribed lesion in the posterior neck, shoulders, and back of older men. SCL of the oral cavity is rare. We present the clinical-pathologic features of the third case of SCL located on the hard palate and discuss the histological differential diagnosis with other fusiform neoplasms. CASE REPORT: A 56-year-old man was evaluated for an asymptomatic swelling on the right side of the hard palate. The intraoral examination showed a 25×20 mm sessile and circumscribed tumor, underlying an apparently healthy mucosa of normal color. The lesion revealed a floating consistency during palpation. Excisional biopsy was carried out based on a clinical diagnosis of lipoma or a benign minor salivary gland tumor. The histopathology demonstrated a well-circumscribed but unencapsulated proliferation of bland spindle cells admixed with mature adipocytes in a collagenous/myxoid stroma. The spindle cells were uniform, exhibiting elongated nuclei and narrow cytoplasmic processes without atypia. They were positive to CD34 and negative to factor VIII, alpha-smooth muscle actin, S100, cytokeratin, and actin. Mitotic activity was low, as confirmed by Ki-67 immunostaining. No lipoblastic activity was found. The diagnosis of SCL was therefore established. CONCLUSIONS: Oral spindle cell lipoma is a rare benign lipomatous tumor. The histologic picture shows a range of variations and the observation of morphological features is important to distinguish this lesion from other fusiform tumors. Immunohistochemistry should be helpful in this differentiation.

Epigenetic regulation of matrix metalloproteinase expression in ameloblastoma.

BACKGROUND: An ameloblastoma is a benign odontogenic neoplasm with aggressive behaviour and high recurrence rates. The increased expression of matrix metalloproteinases (MMPs) has been reported in ameloblastomas. In the present study, we hypothesised that epigenetic alterations may regulate MMP expression in ameloblastomas. METHODS: We investigated the methylation status of the genes MMP-2 and MMP-9 in addition to mRNA transcription and protein expression in ameloblastomas. Methylation analysis was performed by both methylation-specific polymerase chain reaction (MSP-PCR) and restriction enzyme digestion to evaluate the methylation profile of MMP-2 and MMP-9 in 12 ameloblastoma samples and 12 healthy gingiva fragments, which were included as controls. Furthermore, we investigated the transcription levels of the genes by quantitative reverse-transcription PCR (qRT-PCR). Zymography was performed to verify protein expression in ameloblastomas. RESULTS: The ameloblastomas showed a high frequency of unmethylated MMP-2 and MMP-9, whereas the healthy gingival samples presented a sharp prevalence of methylated MMPs. Higher expression levels of MMP-9 were found in ameloblastomas compared to healthy gingiva. However, no significant differences in the MMP-2 mRNA expression between groups was found. All ameloblastomas showed positive expression of MMP-2 and MMP-9 proteins. CONCLUSIONS: Our findings suggest that expression of MMP-9 is increased in ameloblastomas and is possibly modulated by unmethylation of the gene.

miR-15a/16-1 influences BCL2 expression in keratocystic odontogenic tumors.

BACKGROUND: A keratocystic odontogenic tumor (KCOT) is a benign destructive recurrent odontogenic cystic neoplasm. The microRNAs (miRNAs) miR-15a and miR-16-1 function as negative regulators of the anti-apoptotic gene BCL2 at the post-transcriptional level. Notably, high Bcl-2 immunoexpression is found in the epithelial lining of KCOTs, while the loss of Bcl-2 immunopositive cells is observed in marsupialized cysts. The purpose of this study was to investigate whether the transcription of miR-15a and miR-16-1 is altered in KCOTs and whether it is associated with BCL2 gene expression in such lesions. METHODS: Using qRT-PCR and immunohistochemical analyses, we examined miR-15a/16-1 and BCL2 gene expression in KCOTs. The impact of miR-15a/16-1 expression on BCL2 gene translation was investigated by in vitro studies using primary KCOT culture cells. RESULTS: Using qRT-PCR, we observed miR-15a and/or miR-16-1 downregulation in the majority of the KCOT samples (24 of 28). We also observed higher BCL2 mRNA expression in 19 of 20 KCOT frozen samples and moderate to high Bcl-2 immunopositivity in the basal layer cells of 16 of 18 paraffin embedded KCOTs (median: 42.6 %). In vitro over-expression of miR-15a/16-1 in human KCOT-1 primary cell cultures resulted in a decrease in Bcl-2 protein expression. Furthermore, all five paired KCOTs collected before and after marsupialization treatment exhibited an increase in miR-15a after the procedure. CONCLUSIONS: Our results suggest that KCOT neoplastic cells exhibit an anti-apoptotic profile that may be related to lower miR-15a/16-1 expression. Additionally, we demonstrated that miRNA expression increases after marsupialization, implicating an etiological and therapeutic role of miRNAs in KCOT.

Loss of heterozygosity of the PTCH gene in ameloblastoma.

Ameloblastoma is a locally aggressive benign neoplasm derived from odontogenic epithelium, with high recurrence rates. Alterations in the Sonic Hedgehog signaling pathway, including PTCH gene mutations, have been associated with the pathogenesis of some odontogenic tumors. The purpose of the present study was to assess loss of heterozygosity at the PTCH locus in ameloblastoma. Twelve ameloblastomas were included, and loss of heterozygosity was assessed by using 3 microsatellite markers D9S252, D9S127, and D9S287 and 3 single-nucleotide polymorphisms rs112794371, rs111446700, and rs357564, all located at the PTCH gene locus. Furthermore, we investigated GLI1 and GLI2 transcription levels by quantitative reverse transcription polymerase chain reaction in 8 ameloblastomas and, concomitantly, PTCH protein levels by immunohistochemical analysis. Loss of heterozygosity at 9q21.33-9q.31 was detected in 4 (40.0%) of 10 informative cases of ameloblastoma. All 8 analyzed samples expressed GLI1 messenger RNA and 7 cases GLI2 messenger RNA. Interestingly, loss of heterozygosity at the PTCH locus was not correlated with GLI1 or GLI2 transcription levels, nor was there any correlation with PTCH protein expression. In conclusion, our findings suggest that loss of heterozygosity in the PTCH region may be relevant to the pathogenesis of ameloblastoma but may target a different gene than PTCH.

Methylation frequencies of cell-cycle associated genes in epithelial odontogenic tumours.

OBJECTIVE: The benign epithelial odontogenic tumours constitute a group of lesions derived from epithelial elements of the tooth-forming apparatus. This group includes lesions of different biological behaviour, such as ameloblastoma, calcifying cystic odontogenic tumour (CCOT) and adenomatoid odontogenic tumour (AOT). The pathogenesis of these neoplasms remains uncertain and the occurrence of methylation in cell-cycle related genes may be involved in their development. The aim of this study was to investigate the methylation status of P16, P21, P27, P53 and RB1 genes in epithelial odontogenic tumours. DESIGN: Methylation-specific polymerase chain reaction (MSP) was used to evaluate the presence of methylation in 13 samples of ameloblastoma, six samples of CCOT, three samples of AOT and 14 samples of dental follicles, included as control. RESULTS: Our results showed a distinct methylation profile in each group. In ameloblastoma, the highest methylated genes were P16 and P21, while in CCOT the P21 and RB1 genes were the most commonly methylated genes. Only the P16 and P21 genes were methylated in the AOT samples. In the dental follicle samples, P16, P27 and RB1 genes were commonly methylated. A high percentage of the odontogenic tumours analysed showed methylation of the P21 gene, in contrast to dental follicles. CONCLUSIONS: Epithelial odontogenic tumours show a distinct methylation profile in cell-cycle associated genes. In addition to this, the current findings show that epigenetic alterations are common events in epithelial odontogenic tumours.