Oral squamous cell carcinomas and oral potentially malignant disorders: A Latin American study.

OBJECTIVE: To determine the frequency of oral squamous cell carcinoma (OSCC) associated or not with oral potentially malignant disorders (OPMD), and the epidemiological profile and traditional risk factors in Latin America. METHODS: A retrospective observational study was conducted in 17 Latin American centres. There were included cases of OSCC, analysing age, gender, OSCC and their association with previous OPMD. Clinicopathological variables were retrieved. The condition of sequential-OSCC versus OSCC-de novo (OSCC-dn) was analysed concerning the aforementioned variables. Quantitative variables were analysed using Student's t-test, and qualitative variables with chi-square. RESULTS: In total, 2705 OSCC were included with a mean age of 62.8 years old. 55.8% were men. 53.75% of the patients were smokers and 38% were common drinkers. The lateral tongue border was the most affected site (24.65%). There were regional variations in OPMD, being leukoplakia the most frequent. Of the overall 2705 OSCC cases, 81.4% corresponded to OSCC-dn, while s-OSCC were 18.6%. Regarding lip vermillion SCC, 35.7% corresponded to de novo lip SCC and 64.3% were associated with previous OPMD. CONCLUSIONS: In Latin America, OSCC-dn seems to be more frequent with regional variations of some clinical and histopathological features. Further prospective studies are needed to analyse this phenomenon.

Hidden colon adenocarcinoma diagnosed from mouth metastasis: case report and literature review.

BACKGROUND: We report an unusual case of metastatic colon adenocarcinoma to the maxilla as an initial clinical sign of the disease, this being the second case reported in the palate. In addition, we show an extensive review of the literature, with clinical cases of adenocarcinoma with metastasis to the mouth. CASE PRESENTATION: An 80-year-old man complained of "swelling on the palate" with a 3-week evolution time. He reported suffering from constipation and high blood pressure. The intraoral examination revealed a pedunculated, red, and painless nodule on the maxillary gingiva. Under the diagnostic hypotheses of squamous cell carcinoma and malignant neoplasm of the salivary gland, an incisional biopsy was performed. Microscopically, the columnar epithelium was observed forming papillary areas, neoplastic cells with prominent nucleoli, hyperchromatic nuclei, atypical mitotic figures, and mucous cells, being positive for CK 20, suggesting the provisional diagnosis of metastatic adenocarcinoma, probably of gastrointestinal origin. The patient was submitted to endoscopy and colonoscopy exams, and a lesion in the sigmoid region of the colon was observed. After a colon biopsy, a moderately differentiated adenocarcinoma was confirmed, establishing the final diagnosis of metastatic neoplasia of colon adenocarcinoma to the oral lesion. The literature review revealed 45 clinical cases of colon adenocarcinoma with metastasis to the oral cavity. To the best of our knowledge, it is the second case on the palate. CONCLUSIONS: Colon adenocarcinoma with metastasis to the oral cavity is rare but should be included in the differential diagnosis of neoplasms of the oral cavity, even when there are no known primary tumors in some cases, and this may be the first indication of the presence of a tumor.

Prevalence of human papillomavirus 6 and 11 variants in recurrent respiratory papillomatosis.

Human papillomavirus (HPV) types 6 and 11 are the etiological agents of recurrent respiratory papillomatosis (RRP). We examined the prevalence and distribution of HPVs 6 and 11 genetic variants in juvenile onset (JORRP) and adult onset (AORRP) laryngeal papillomas. Cases of JORRP and AORRP were collected, retrospectively. HPV detection and genotyping were accessed by polymerase chain reaction-sequencing in 67 RRP samples. Overall, the most prevalent HPV-6 variants were from B1 (55.8%) and B3 (27.9%) sublineages, whereas among HPV-11 positive samples A2 (62.5%) variants were predominant. A higher prevalence of HPV-6 B1 was observed in JORRP (83.3% B1 and 16.7% B3), compared with AORRP cases (58.3% B1 and 41.7% B3). HPV-11 A2 variants were more prevalent both in JORRP (57.2%) and in AORRP cases (70.0%). Nevertheless, with the exception that HPV-6 B1 were significantly less likely to recur, there was a lack of association between any particular HPVs 6 or 11 variant and clinicopathological features. Our data do not support an association between HPVs 6 and 11 variability and RRP.

Oral hairy leukoplakia in a child using a corticosteroid nasal spray.

We report a case of atypical oral hairy leukoplakia (OHL) in a 9-year-old immunocompetent girl treated with fluticasone propionate nasal spray for allergic rhinitis. The OHL in childhood is uncommon and should be included in a differential diagnosis of white lesions in the oral mucosa.

Relationship between inflammation and the severity of Recurrent Respiratory Papillomatosis.

OBJECTIVE: To characterize inflammatory cells in Recurrent Respiratory Papillomatosis (RRP) and to correlate it with severity using the Derkay laryngoscopic scale. MATERIALS AND METHODS: The data and biopsies from 36 patients with Juvenile (JRRP) and 56 patients with Adult (ARRP) were collected and analyzed under light microscopy. The patients were separated into groups according to the Derkay index: ≥20 for the most severe and < 20 for the less severe cases. Immunohistochemical analysis using CD3, CD4, CD8, CD15, CD20, CD68, FoxP3 and MUM-1 antibodies was performed, and the inflammatory cells were quantified. All the clinicopathological characteristics and the results of the immunohistochemical analysis were compared among the groups proposed using the Chi-Square test and correlated through the Spearman correlation test. RESULTS: The ARRP showed significantly higher quantities of CD3+, CD8+ and MUM1+ cells (p < .05) than the JRRP samples. The presence of CD15+ cells showed positive correlation with the Derkay index (p < .05), while the MUM-1+ cells showed an inverse correlation (p = .01). CONCLUSION: There are differences between the inflammatory cells population in the juvenile and adult groups and it can be related to disease severity.

Systemic and local effects of radiotherapy: an experimental study on implants placed in rats.

OBJECTIVES: Evaluate the modulating effect of ionizing radiation, blood cytokine levels, and bone remodeling of the interface around the implant to understand the radiation mechanisms which can impair the implants receptor site. MATERIAL AND METHODS: Sixty rats were submitted to grade V titanium implants in the femurs and were divided into the following groups: no-irradiation (N-Ir): control group with implant only; early-irradiation (E-Ir): implant + irradiation after 24 h; late-irradiation (L-Ir): implant + irradiation after 4 weeks; and previous-irradiation (P-Ir): irradiation + implant after 4 weeks. The animals in the E-Ir, L-Ir, and P-Ir groups were irradiated in two fractional stages of 15 Gy. At 3 days, 2 weeks, and 7 weeks after the final procedure, five animals were randomly euthanized per group. Serum levels of TNF-ɑ, IL-1ß, TGF-ß, IL-6, M-CSF, and IL-10 were measured from blood collected prior to euthanasia using the ELISA test. The pieces containing the implants were subjected to immunohistochemical labeling using the tartrate acid resistant to phosphatase, osteocalcin, and caspase-3 markers and mCT. The ANOVA test was used for statistical analysis, and the Tukey multiple comparison test (p < 0.05) was applied. RESULTS: The results indicated that ionizing radiation modifies the production of pro- and anti-inflammatory serum cytokines, the expression of proteins involved in bone remodeling and cellular apoptosis, as well as changes in bone formation. CONCLUSIONS: The results suggests that a longer period between radiotherapy and implant placement surgery when irradiation occurs prior to implant installation would allow the recovery and renewal of bone cells and avoid future failures in osseointegration. CLINICAL RELEVANCE: The search for modifications caused by ionizing irradiation in bone tissue can indicate the ideal period for implant placement without affecting the osseointegration process.

Different patterns of expression of cell cycle control and local invasion-related proteins in oral squamous cell carcinoma affecting young patients.

OBJECTIVES: Oral squamous cell carcinoma (OSCC) predominantly affects males in the fifth decade of life; nevertheless, an increased incidence in young patients has been reported worldwide, and the clinical and behavioral characteristics of tumors in this group are controversial, and the literature shows divergent results. PURPOSE: To investigate the clinicopathological features and prognostic significance of the immunoexpression of cell cycle and local invasion proteins in OSCC affecting young patients (≤40 years old). METHODS: A tissue microarray was performed with 132 OSCC samples (61 cases of young patients vs 71 cases of elderly patients) and submitted to immunohistochemical reactions with Ki67, p53, p16, Bcl-2, Cyclin D1, C-ErbB2, p21, Myc, EGFR, MMP-9, SMA, Cathepsin K and FGF-2 antibodies. RESULTS: Clinicopathological features and survival rates were similar in both groups. Although overexpression of EGFR (P=.042) and MMP-9 (P=.001) was more frequent in young patients, only C-ErbB-2 (P=.048) and SMA (P=.048) expression correlated with lower disease-free survival (DFS) in this group of patients. CONCLUSION: Clinicopathological features and survival rates are similar between younger and older patients with OSCC. The different patterns of C-ErbB2, EGFR, MMP-9, and SMA expression between the groups merits further investigation to understand their role in the early tumor onset in young patients.

The Role of New Removable Complete Dentures in Stimulated Salivary Flow and Taste Perception.

PURPOSE: To evaluate the effect of replacement of inadequate complete dentures on salivary flow and taste perception in geriatric patients. MATERIALS AND METHODS: Thirty-three patients, 13 males and 20 females, with a mean age of 64.4 years were submitted to stimulated and unstimulated salivary flow rate and salivary pH measurements, and sense of taste evaluation. Tests were performed 3 months before complete denture substitution and 3 weeks after denture insertion. RESULTS: The mean for unstimulated saliva (USS) was 2.1 ml before and 2.7 ml after replacement (p = 0.003). The mean volume of stimulated saliva was 6.3 ml before and 8.2 ml after replacement (p = 0.004). The pH mean of USS was 7.8 ± 0.44 before and 8.02 ± 0.41 after replacement (p = 0.005). No statistically significant difference was determined in the sense of taste before and 3 weeks after complete denture replacement. CONCLUSIONS: The replacement of inadequate complete dentures increases saliva flow; however, it does not improve taste perception.

Oral syphilis: report of three cases and characterization of the inflammatory cells.

Syphilis is a sexually transmitted infectious disease caused by Treponema pallidum. This study reports 3 cases of syphilis and highlights the importance of identifying oral lesions for its final diagnosis. Case 1: a 48-year-old male patient presented with a bleeding ulcer in the lower lip. Overall clinical examination revealed patchy alopecia and skin target lesions. Case 2: a 61-year-old male patient presented with white spots on the lateral tongue and nodules on the dorsum of the tongue. Overall clinical examination showed erythematous target lesions on the abdomen, forearm, palms of the hand, and soles of the feet. Case 3: a 17-year-old male patient presented with an ulcerated lesion on the tongue and lymph node involvement. The following serologic tests were requested: Venereal Disease Research Laboratory, fluorescent treponemal antibody-absorption, anti-HIV-1 and anti-HIV-2, and anti-hepatitis C virus. An incisional biopsy revealed epithelial hyperplasia associated with intense and diffuse mononuclear inflammatory cell infiltration consisting mainly of plasma cells, in a perivascular and perineural distribution. The final diagnosis in the 3 patients was syphilis. Treatment consisted of 1 weekly dose of penicillin (2.4 million units, intramuscular) for 2 or 3 weeks. Immunohistochemical reactions for XIIIa, CD3, CD20, CD68, CD163, S100, CD1a, CD11c, CD83, CD138, and CD208 were performed. Clinicians should be familiarized with oral syphilis lesions in order to be able to diagnose this emerging infectious disease of variable clinical presentation.

Report of intraosseous intravascular papillary endothelial hyperplasia associated with an odontogenic cyst in the maxilla and literature review.

Intravascular papillary endothelial hyperplasia (IPEH) represents an uncommon reactive endothelial hyperplastic proliferation. A 46-year-old man experienced increased volume in the right maxilla, elevation of the nasal ala, and swelling of the hard palate with a reddish hue for 3 months. Computed tomography revealed an expansive hypodense region and cortical bone destruction associated with an impacted supernumerary tooth and an endodontically treated tooth. Under the differential diagnoses of a radicular cyst, dentigerous cyst, and ameloblastoma, an exploratory aspiration and incisional biopsy were performed. This revealed the formation of blood vessels of various diameters lined by endothelium, forming intravascular papillae positive for CD-34. The definitive diagnosis was IPEH, and the patient was treated by embolization and surgery. Histological analysis confirmed the presence of IPEH associated with an odontogenic cyst. After 12 months of follow-up, no recurrence was observed. Also, we reviewed case reports of IPEH affecting the maxilla and mandible. Fourteen intraosseous cases were reported in the maxilla and mandible, with a preference for males and affecting a wide age range. Complete surgical excision was the treatment of choice, and recurrences were not reported. The pathogenesis of IPEH is controversial and may originate from trauma or inflammatory processes. To the best of our knowledge, this is the first report of an association of IPEH with an odontogenic cyst. The importance of IPEH in the differential diagnosis of intraosseous lesions in the jaws is emphasized, and preoperative semiotic maneuvers are needed to prevent surgical complications.

Effects of artemisinin and cisplatin on the malignant progression of oral leukoplakia. In vitro and in vivo study.

OBJECTIVES: Chemoprevention can be a treatment for potentially malignant lesions (PMLs). We aimed to evaluate whether artemisinin (ART) and cisplatin (CSP) are associated with apoptosis and immunogenic cell death (ICD) in vitro, using oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) cell lines, and whether these compounds prevent OL progression in vivo. METHODS: Normal keratinocytes (HaCat), Dysplastic oral cells (DOK), and oral squamous cell carcinoma (SCC-180) cell lines were treated with ART, CSP, and ART + CSP to analyze cytotoxicity, genotoxicity, cell migration, and increased expression of proteins related to apoptosis and ICD. Additionally, 41 mice were induced with OL using 4NQO, treated with ART and CSP, and their tongues were histologically analyzed. RESULTS: In vitro, CSP and CSP + ART showed dose-dependent cytotoxicity and reduced SCC-180 migration. No treatment was genotoxic, and none induced expression of proteins related to apoptosis and ICD; CSP considerably reduced High-mobility group box-1 (HMGB-1) protein expression in SCC-180. In vivo, there was a delay in OL progression with ART and CSP treatment; however, by the 16th week, only CSP prevented progression to OSCC. CONCLUSION: Expression of proteins related to ICD and apoptosis did not increase with treatments, and CSP was shown to reduce immunogenic pathways in SCC-180, while reducing cell migration. ART did not prevent the malignant progression of OL in vivo; CSP did despite significant adverse effects.

Stimulator of Interferon Genes Pathway Activation through the Controlled Release of STINGel Mediates Analgesia and Anti-Cancer Effects in Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) presents significant treatment challenges due to its poor survival and intense pain at the primary cancer site. Cancer pain is debilitating, contributes to diminished quality of life, and causes opioid tolerance. The stimulator of interferon genes (STING) agonism has been investigated as an anti-cancer strategy. We have developed STINGel, an extended-release formulation that prolongs the availability of STING agonists, which has demonstrated an enhanced anti-tumor effect in OSCC compared to STING agonist injection. This study investigates the impact of intra-tumoral STINGel on OSCC-induced pain using two separate OSCC models and nociceptive behavioral assays. Intra-tumoral STINGel significantly reduced mechanical allodynia in the orofacial cancer model and alleviated thermal and mechanical hyperalgesia in the hind paw model. To determine the cellular signaling cascade contributing to the antinociceptive effect, we performed an in-depth analysis of immune cell populations via single-cell RNA-seq. We demonstrated an increase in M1-like macrophages and N1-like neutrophils after STINGel treatment. The identified regulatory pathways controlled immune response activation, myeloid cell differentiation, and cytoplasmic translation. Functional pathway analysis demonstrated the suppression of translation at neuron synapses and the negative regulation of neuron projection development in M2-like macrophages after STINGel treatment. Importantly, STINGel treatment upregulated TGF-ß pathway signaling between various cell populations and peripheral nervous system (PNS) macrophages and enhanced TGF-ß signaling within the PNS itself. Overall, this study sheds light on the mechanisms underlying STINGel-mediated antinociception and anti-tumorigenic impact.

Detection of cytokeratins in ghost cells of calcifying cystic odontogenic tumor indicates an altered keratinization and hair follicle differentiation for their development.

Calcifying cystic odontogenic tumors (CCOTs) are benign cystic lesions of odontogenic origin characterized by an ameloblastoma-like epithelium and the presence of a group of cells named ghost cells. The pattern of cytokeratin (Ck) expression on these lesions remains unclear and needs to be clarified. To this end, the expression of Ck6, Ck13, Ck14, Ck18, and Ck19 in the epithelium lining of 7 cases of CCOTs was evaluated by immunohistochemistry. For this, the epithelium lining was divided into 3 distinct regions: basal layer, suprabasal layer, and the compartment composed of ghost cells. In this study, 6 cases (85.7%) were classified as type 1 and 1 (14.3%) as type 4. All cases were negative for Ck13 and Ck18, despite the epithelial layer, as well as in the ghost cells. Ck6 was only positive in the ghost cells. Positivity for Ck14 and Ck19 was found in the basal and suprabasal layers, including the ghost cells. The results showing positivity for Ck14 and Ck19 in all of the analyzed cases reinforce CCOT as being of odontogenic origin, and the restricted expression of Ck6 in the ghost cells may be indicative that these cells suffer an altered differentiation into hair follicles in CCOTs.

Unveiling an oral hemangiolymphangioma.

Hemangiolymphangioma is a very rare vascular malformation that develops as a combination of dilated venous and lymphatic vessels. We describe an unusual case of hemangiolymphangioma of the tongue affecting an adult man who complained of an uncomfortable, slowly progressing exophytic irregular dark red-violaceous nodular mass on his tongue that impaired speech and swallowing for two weeks. The clinical differential diagnoses were Kaposi's sarcoma and a COVID-19-related lesion. A complete blood count and serology for HIV-1 and 2 and RT-PCR for COVID-19 were requested and results were negative. An incisional biopsy was performed. Microscopically, the lesion exhibited several dilated vessels lined by normal-appearing endothelial cells, some filled with prominent intravascular erythrocytes and others containing proteinaceous eosinophilic material resembling lymphatic vessels, in close association with hyperkeratosis, papillomatosis, and acanthosis. From immunohistochemical analysis, most vessels were found to be CD34 positive, some highlighted by α-SMA, whereas D2-40 was focal. Positive staining for some lymphatic and blood vessel markers, i.e., D2-40 and CD34, respectively, indicates a mixed derivation of the lesion. HHV-8 was negative. Clinical features, the congested blood vessels with ectasia in intimate association with hyperplastic epithelium, and the immunohistochemical profile supported the final diagnosis of oral hemangiolymphangioma. The patient underwent minimally invasive surgical excision with no intercurrences. After 18 months of follow-up, there were no signs of relapse.

Evaluation of the Effects of Radiation Therapy on Muscle Contractibility and Skin Healing: An Experimental Study of the Cancer Treatment Implications.

BACKGROUND: Radiotherapy can affect healthy cells, resulting in side effects. This study aimed to assess the impact of radiotherapy on soft tissue in surgical wounds in rats. METHODS: The animals were divided into four groups: control (S) group without irradiation, immediate irradiation (S-IIr) group receiving irradiation right after surgery, late irradiation (S-LIr) group receiving irradiation four weeks after surgery, and early irradiation (Ir-S) group receiving irradiation before surgery. The irradiated groups underwent two fractional stages of 15 Gy. Muscle contractibility (EMG) was evaluated at two different time points, and after 2 and 7 weeks, the animals were euthanized for histological analysis of the muscles and skin. RESULTS: There was no significant difference between the EMG1 and EMG2 values of the S and S-LIr groups, but both S-IIr and Ir-S groups exhibited a statistically significant difference. The S group demonstrated a larger diameter of muscle fiber compared to other groups, showing a significant difference. In terms of skin analysis, the S-IIr group had the least inflammatory infiltrate and the highest amount of red fibers, differing significantly from the other groups. CONCLUSIONS: Regardless of the duration, radiotherapy was found to have effects on the surrounding soft tissues, as concluded by this study.

New Insights into the Impact of Human Papillomavirus on Oral Cancer in Young Patients: Proteomic Approach Reveals a Novel Role for S100A8.

Human papillomavirus (HPV) infection has recently been linked to a subset of cancers affecting the oral cavity. However, the molecular mechanisms underlying HPV-driven oral squamous cell carcinoma (OSCC) onset and progression are poorly understood. METHODS: We performed MS-based proteomics profiling based on HPV status in OSCC in young patients, following biological characterization and cell assays to explore the proteome functional landscape. RESULTS: Thirty-nine proteins are differentially abundant between HPV (+) and HPV (-) OSCC. Among them, COPS3, DYHC1, and S100A8 are unfavorable for tumor recurrence and survival, in contrast to A2M and Serpine1, low levels of which show an association with better DFS. Remarkably, S100A8 is considered an independent prognostic factor for lower survival rates, and at high levels, it alters tumor-associated immune profiling, showing a lower proportion of M1 macrophages and dendritic cells. HPV (+) OSCC also displayed the pathogen-associated patterns receptor that, when activated, triggered the S100A8 and NFκB inflammatory responses. CONCLUSION: HPV (+) OSCC has a peculiar microenvironment pattern distinctive from HPV (-), involving the expression of pathogen-associated pattern receptors, S100A8 overexpression, and NFκB activation and responses, which has important consequences in prognosis and may guide therapeutic decisions.

High-risk human papillomavirus in oral squamous cell carcinoma of young patients.

The aim of this study was to investigate a possible relation between oral squamous cell carcinoma (SCC), the presence of high-risk human papillomavirus (HR-HPV) DNA and p16 expression in young patients. Paraffin-embedded tumor blocks from 47 oral SCC of young (≤40-year old) patients were evaluated. The presence of HPV DNA in tumor specimens was analyzed by polymerase chain reaction (PCR) using GP5+/GP6+ generic primers (L1 region) followed by dot blot hybridization for HPV typing. When necessary, the HPV16 positivity was confirmed by PCR HPV16 E7-specific primers. Cases involving young patients were compared with 67 oral SCC from patients ≥50-year old (controls). Demographic and clinical data were collected to analyze patient outcomes. p16(ink4) expression was evaluated by immunostaining of tissue microarrays. HPV16 was detected in 22 (19.2%) cases; 15 (68.2%) young and 7 (31.8%) control patients, a statistically significant difference (p = 0.01). In 1 (1.7%) young group specimen, HPV DNA 16 and 18 was detected. p16 expression was observed in 11 (25.6%) cases from the young group and in 11 (19.6%) controls (p = 0.48). Association between HPV and p16 was verified, and it was statistically significant (p = 0.002). The higher prevalence of high-risk HPV types, especially HPV16, may be a contributing factor to oral carcinogenesis in younger individuals.

Oral squamous cell carcinoma outcome in adolescent/young adult: Systematic review and meta-analysis.

To perform a systematic review focusing on the prognosis of oral cavity squamous cell carcinoma (OSCC) in young patients (≤40 years old) compared to older (>40 years old). Four databases were used in our search strategy. First, all titles were systematically organized using the Covidence platform online. In the second phase, 118 full texts of potentially eligible studies were analyzed by reviewers independently and in pairs. Twelve studies were considered eligible for data extraction. The relapse was higher in the young than in controls (pooled relative risk (RR) = 1.31; 95% CI [1.10-1.56]). The 5-year disease-free survival (DFS) was worse in young group (pooled hazard ratio (HR) = 0.73; 95% CI [0.63-0.85]) but the 5-year overall survival (OS) estimate was similar between the groups (pooled HR = 0.84; 95% CI [0.70-1.00]). While the 5-year OS was similar between groups, the number of relapses and 5-year DFS were worse in patients with OSCC ≤40 years old.

Melkersson Rosenthal syndrome: a histopathologic mystery and dermatologic challenge.

Melkersson Rosenthal syndrome (MRS) is rare disease of unknown etiology characterized by orofacial edema, facial nerve palsy and fissured tongue. Microscopically, it shows epithelioid non-caseous granulomas; however, edema and perivascular lymphocytic infiltrates have been described. Two different clinical forms of MRS are presented in this report. In the complete form (Case 1), the main histopathologic finding was a non-necrotizing granulomatous inflammation with 56% of the total number of cells composed of B cells (CD 20(+) ) principally located in the granuloma's center and 33% being T cells predominating in the surrounding area, of which 48% were CD 4(+) and 16% were CD 8(+) lymphocytes. In the monosymptomatic form (Case 2), the inflammatory cells were dispersed into the connective tissue without granulomatous formation. B cells were scanty, and 78% of the cells were CD 45(+) T cells, with 46% and 34%, CD 8(+) and CD 4(+) phenotype, respectively. These cases showed different clinical, histopathological and immunohistochemical forms of MRS, suggesting different host immune responses.

Central Odontogenic Fibroma with the Presence of Large Fibroblasts of Varying Morphology.

A patient with an odontogenic fibroma (OF) with the presence of fibroblasts of varying morphology is presented, and the main microscopic differential diagnosis is discussed. Case report: a 51-year-old man complained of a swelling in the anterior region of the mandible. The panoramic radiograph showed a radiolucent, well-defined multilocular image, with displacement of the roots of the left mandibular incisors and canine. A cone beam computed tomography examination revealed a hypodense image, with delicate bone spicules inside, divergence of the tooth roots and destruction of the buccal cortical bone. Under the differential diagnosis of a desmoplastic ameloblastoma or a squamous odontogenic tumor, an incisional biopsy was made. Microscopically, deeply collagenized tissue with scarce odontogenic epithelium islands, large fibroblasts of varying morphology and calcified material was observed. A diagnosis of OF was made. Surgical removal was carried out, and the specimen was examined. Identical aspects were found, and the immunohistochemical reaction for pan-cytokeratin was carried out to identify the odontogenic epithelial cells. The definitive diagnosis of OF was confirmed, and we emphasize the importance of the correlation of all characteristics for a definitive diagnosis.