Central Mucoepidermoid Carcinoma Radiographically Mimicking an Odontogenic Lesion.

Central mucoepidermoid carcinoma (CMEC) is a rare pathological entity with only a few case reports in the literature. The present case reported an uncommon occurrence of CMEC mimicking an odontogenic lesion in a young patient. A 17-year-old female patient sought dental care due to a slight swelling located in the posterior region of the mandible on the left side. Radiographic exams revealed an osteolytic lesion with defined limits in relation to proximity to the pericoronal follicle of tooth #38. The clinical and radiographic diagnostic hypothesis was an odontogenic lesion. Histological sections showed the presence of a neoplasm of glandular origin, not encapsulated, with a predominantly cystic growth pattern. The neoplasm consisted of mucous, intermediate, and squamous cells. In the immunohistochemical staining, the neoplastic cells were positive for cytokeratin 7. Mucous cells were positive for PAS with diastase digestion. The final diagnosis consisted of mucoepidermoid carcinoma. The tumor was removed surgically, and the patient has shown no signs of relapse nor recurrence. In conclusion, CMEC may mimic radiographic features of various pathologies, but despite its rarity, clinicians and oral radiologists should consider CMEC as a diagnostic hypothesis for jaw lesions.

Adenomatoid odontogenic tumor: Features of ameloblastic-like epithelial cells differentiation, secretion, and the nature of tumor cells products.

BACKGROUND: This study aimed to investigate the differentiation of ameloblastic-like cells and the nature of the secreted eosinophilic materials in adenomatoid odontogenic tumors. METHODS: We studied histological and immunohistochemical characteristics of 20 cases using: cytokeratins 14 and 19, amelogenin, collagen I, laminin, vimentin, and CD34. RESULTS: Rosette cells differentiated into ameloblastic-like cells positioned face-to-face, displaying collagen I-positive material between them. Epithelial cells of the rosettes can differentiate into ameloblastic-like cells. This phenomenon probably occurs due to an induction phenomenon between these cells. The secretion of collagen I is probably a brief event. Amelogenin-positive areas were interspersed by epithelial cells in the lace-like areas, outside the rosettes and distant from the ameloblastic-like cells. CONCLUSIONS: There are at least two types of eosinophilic material in different areas within the tumor, one in the rosette and solid areas and another in lace-like areas. The secreted eosinophilic material in the rosettes and solid areas is probably a product of well-differentiated ameloblastic-like cells. It is positive for collagen I and negative for amelogenin, whereas some eosinophilic materials in the lace-like areas are positive for amelogenin. We hypothesize that the latter eosinophilic material could be a product of odontogenic cuboidal epithelial or intermediate stratum-like epithelial cells.

Oral epithelial dysplasia grading: Comparing the binary system to the traditional 3-tier system, an actuarial study with malignant transformation as outcome.

BACKGROUND: Establishing the risk of malignant transformation (MT) in oral leukoplakia is usually based on grading oral epithelial dysplasia (OED) on biopsy tissue, for which two systems are proposed: a 3-tier and a binary system. Only very few actuarial studies have tested the accuracy of such methods in predicting MT, especially for the binary system. This study aimed to assess the accuracy of the two grading systems in predicting MT in a cohort of oral leukoplakia (OL) from Brazil, with follow-up data. METHODS: The sample comprised 878 individuals diagnosed with OL from 2005 to 2018. Follow-up data were obtained both locally and from the regional cancer registry. All lesions were graded using both the 3-tier and the binary systems. Kaplan-Meier curves (Log-rank Mantel-Cox) were used to assess risk and kappa to assess interobserver agreement. RESULTS: Thirty-five individuals underwent MT (4%). Both systems demonstrated prognostic value, though the 3-tier system proved superior, with OR 9.23 (3.42-23.69), PPV 0.152, NPV 0.98, compared to binary OR 3.49 (1.79-6.79), PPV 0.079, NPV 0.976. Interobserver agreement was also superior in the 3-tier system (0.47, p < 0.05) compared to the binary system (0.139, p = 0.39). Combining the two systems enhanced prognostic values (OR 14.28, PPV 0.217, NPV 0.981). CONCLUSION: The 3-tier system presented superior prognostic value to the binary system. Combining both systems to double-grade intermediate lesions might enhance risk assessment.

Histological and mast cells evaluation after application of botulinum toxin type a in masseter muscles of rats.

Background: Botulinum Toxin Type A (BTX-A) has been largely used to reduce muscle strength of masseter and temporal muscles by producing a temporary weakening of their activity. This study aimed to evaluate the histological changes and the number of mast cells after the injection of BTX-A. Material and Methods: In the masseter muscle of rats in the periods of 1, 7, 15, and 30 days. These muscles were stained with hematoxylin and eosin (H&E) and toluidine blue (TBO). The presence or absence of an inflammatory process and necrosis were analyzed by H&E in all area of the slide at 10X magnification. The number of mast cells was evaluated by counting 10 "hotspots" in the intra-muscular region on TBO-stained slides, 400X magnification. Statistical analysis was performed through two-way analysis of variance and Tukey's test. Results: As a result, the inflammatory process and necrosis were not observed in any periods studied in both groups Regarding mast cells, there was no statistically significant increase in their quantity in the study group when compared to the control group in the evaluation periods of 7 days and 15 days. However, these mast cells increased significantly during the periods of 1 and 30 days. Conclusions: This study showed that even in the absence of an inflammatory process, there was an increase in the number of mast cells in the first 24 hours after the application of BTX-A, with a subsequent balance between the numbers of mast cells at 7 and 15 days, and again an increase after 30 days. Key words:Botulinum toxins type A, mast cells, masseter muscle.

Primary Intraosseous Synovial Sarcoma in the Mandible.

Synovial sarcoma (SS) is a rare malignant mesenchymal tumor that mainly occurs in body extremities, being uncommon in the head and neck region. In the present study, we described a case of primary intraosseous SS arising in the mandible of a 22-year-old young male. The patient reported a painful swelling on the left side of the mandible for the last 7 months. Imaging exams showed the presence of an expansive and multilocular radiolucent lesion, extending from the left condyle to the mandibular body. The clinic diagnostic hypotheses were ameloblastoma or malignant neoplasm. Histologically, the lesion was characterized by a proliferation of spindle cells exhibiting vesicular nuclei and evident nucleolus. Neoplastic cells were positive for AE1/AE3, cytokeratin 7, vimentin, CD-99, and TLE-1 and negative for CD-34, S-100, SMA, and HHF-35. A combination of clinical, histologic, and immunohistochemical characteristics supported the diagnosis of SS. The patient was referred for treatment, and preoperative exams did not reveal any other tumor foci in the body of the patient. The final diagnosis was of a primary intraosseous SS of the mandible.

Autophagy upregulation may explain inhibition of oral carcinoma in situ by photobiomodulation in vitro.

There is currently no clear understanding on the pathways involved in the process of cell inhibition by photobiomodulation (PBM). The present study evaluated the influence of PBM on the expression of autophagy markers in vitro in an in situ model of oral carcinoma. Oral squamous cell carcinoma (Cal27) and stromal fibroblasts (FG) cultures were used. The independent variables were 'cell type' (FG and CAL27) 'culture condition' (monocultures or co-cultures) and PBM (placebo and 36 J/cm2). The cultures were irradiated from a red LED source for mRNA expression and protein expression analyses. The autophagy markers evaluated were Beclin-1, LC3B and p62 as well as adjuvant markers (BAX Bcl-2, VEGF, CD105, CD34, PRDX1, PRDX4 and GRP78). The Cal27 cells upregulated the autophagy markers upon exposure to PBM both at the mRNA and protein expression levels, providing evidence to explain malignant cell inhibition by PBM.

Uncommon Pigmented Carcinoma In Situ: Case Report and Brief Review.

Pigmented lesions of the oral mucosa encompass several benign and malignant conditions that may be a matter of concern under both clinical and histopathological views. We reported a case of a 62-year-old woman, presenting with an asymptomatic, deeply pigmented lesion on the soft palate. On examination, it appeared asymmetrical, with irregular borders and an area of ulceration. A biopsy, taken to rule out melanoma, revealed a pigmented carcinoma in situ. Throughout the tumor thickness, numerous interspersed melanocytes were found that did not extend to neighboring epithelium. These were large, richly dendritic, and presented abundance of melanin granules and small nuclei. Mild melanin incontinence was found. Scanty transfer of pigment to dysplastic epithelial cells was found through Fontana Masson staining. On immunohistochemical analyses, there were pancytokeratin-stained tumor epithelial cells; increased cell proliferation throughout the entire thickness of the tumor was emphasized by Ki-67 immunomarking. P16 was negative. The dendritic cells were selectively stained for S-100, HMB45 and Melan A. Wide spectrum in situ hybridization for human papillomavirus (HPV) was negative. Unfortunately, following diagnosis, the patient refused any treatment option. Pigmented squamous cell carcinoma with melanocyte colonization must be taken into account in the differential diagnosis of pigmented lesions of the oral cavity.

Expression of invadopodia markers can identify oral lesions with a high risk of malignant transformation.

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor of the oral cavity and is usually preceded by a range of premalignant tissue abnormalities termed oral potentially malignant disorders. Identifying malignant transformation is critical for early treatment and consequently improved survival and decreased morbidity. Invadopodia (INV) are specialized subcellular structures required for cancer cell invasion. We developed a new method to visualize INV in keratinocytes using fluorescent immunohistochemistry (FIHC) and semi-automated images analysis. The presence of INV was used to determine the risk of malignant transformation. We analyzed 145 formalin-fixed, paraffin-embedded (FFPE) oral biopsy samples from 95 patients diagnosed as nondysplastic, dysplastic, and OSCC including 49 patients whose lesions transformed to OSCC (progressing) and 46 cases that did not transform to OSCC (control). All samples were stained for Cortactin, tyrosine kinase substrate with five SH3 domains (Tks5) and matrix metallopeptidase 14 (MMP14) using FIHC, imaged using confocal microscopy and analyzed using a multichannel colocalization analysis. The areas of colocalization were used to generate an INV score. Using the INV score, we were able to identify progressing lesions with a sensitivity of 75-100% and specificity of 72-76%. A positive INV score was associated with increased risk of progression to OSCC. Our results suggest that INV markers can be used in conjunction with the current diagnostic standard for early detection of OSCC.

Leiomyoma of the Cheek.

Leiomyomas are rare benign tumors that grow in the tunica media of smooth muscle cells. Leiomyomas occur most frequently in the uterus or gastrointestinal tract and only very rarely in the area of the cheek. This study reports on a rare case of a leiomyoma in the cheek of a 43-year-old woman, who presented with a well-circumscribed, asymptomatic, mobile swelling in the right cheek. This swelling was slightly purplish in color and measured approximately 4 cm × 3 cm. Surgical excision was the treatment of choice, and the diagnosis was based on histopathological and immunohistochemical stains, which were positive for actin and desmin and negative for AE1/AE3, CD34, and S100. The patient's follow-up, two years later, showed no recurrence, and she has been asymptomatic since the surgery.

Dental Germ Tumor: An Unusual, Cystic, Mixed Epithelial-Mesenchymal Odontogenic Tumor.

Although odontogenic lesions have been extensively described and studied, anomalous, challenging cases occasionally come to the attention of the pathologist. Here, we report the clinical and microscopic characteristics of an unusual cystic lesion of odontogenic origin. A 16-year-old male presented with swelling and pain to palpation of the right mandible as well as numbness of the right lower lip. Radiographically, the corresponding lesion was well-defined and radiolucent with internal radiopaque foci. It extended from the right first premolar posteriorly, approaching the angle of the mandible, and involved the mandibular first molar which was impacted and displaced. The second and third right mandibular molars were also impacted and displaced. The patient was treated by excisional biopsy under general anesthesia. The histopathologic examination revealed the presence of multicystic areas lined by a thin, non-keratinizing squamous epithelium that resembled the epithelial lining of a dentigerous cyst. In continuity with the cystic lining, areas of myxoid tissue reminiscent of dental papilla were observed. The myxoid tissue formed structures that were surfaced by an epithelium comprising a basal layer of ameloblast-like cells with reverse polarity of the nuclei. Above the basilar cells, additional layers of epithelial cells composed a structure resembling the enamel organ. Subjacent to the basilar ameloblast-like cells, a condensation of mesenchymal cells with polarized nuclei opposite to the ameloblast-like cells was present. These mesenchymal cells resembled odontoblasts. In addition, numerous mineralized structures amongst the odontogenic epithelial tissue were present. To date, the patient remains well and without evidence of recurrence after 36 months of follow-up.

Epithelial membrane antigen and DOG1 expression in minor salivary gland tumours.

Epithelial membrane antigen (EMA) and DOG1 are used as marker of epithelial cells, particularly the luminal cells, of salivary gland tumours. The aim of this study was to compare the EMA and DOG1 expression in tumours of minor salivary glands. Cases of pleomorphic adenoma (PA), basal cell adenoma (BCA), canalicular adenoma (CA), adenoid cystic carcinoma (ACC), polymorphous adenocarcinoma (PAC), mucoepidermoid carcinoma (MEC) and epithelial-myoepithelial carcinoma (EMC) were submitted to immunohistochemistry for EMA and DOG1. In PA and BCA, EMA and DOG1 were observed in luminal cells, while in CA the tumour cells were negative for both proteins. The EMA and DOG1 pattern expression detected in EMC was similar to that one observed in benign tumours. In ACC, both myoepithelial e epithelial expressed EMA and DOG-1. PAC tumour cells were only positive for DOG1, whereas MEC were only positive for EMA. In conclusion, EMA and DOG1 expression in benign salivary gland tumours was similar to normal salivary gland tissue and can be used as good marker of tumoral cells derived from intercalated ducts or its progenitor cells, while in malignant salivary gland tumours EMA expression is, however, better used as an indicator of aggressive behavior than a marker of luminal cells.

Estrogen Receptor, Progesterone Receptor, and HER-2 Expression in Recurrent Pleomorphic Adenoma.

Pleomorphic adenoma (PA) is the most common salivary gland neoplasm and, although mostly benign, recurrences, being called recurrent pleomorphic adenoma (RPA) and malignant transformation to carcinoma ex pleomorphic adenoma (CXPA), do occur. Recently, attention has been focused on molecular targeted cancer therapy in various tumors, including salivary gland tumors. The aim of this study was to investigate the role of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) in PA, RPA, and CXPA. In total, 20 cases of PA, 18 of RPA, and 7 cases of CXPA were immunohistochemically studied for ER, PR, and HER-2. For evaluation of ER and PR, only nuclear expression and greater than 10% positive cells were regarded as cutoff criteria. HER-2 was evaluated semiquantitatively and graded from 0 to 3+. HER-2 amplification was assessed by chromogenic in situ hybridization (CISH). Tumors were negative for ER, PR, and HER-2 in all cases of PA and RPA. A case of CXPA showed moderate and complete membranous staining, and 6 cases were negative. HER-2 amplification was not observed in any case. In conclusion, the lack of ER, PR, and HER-2 expression in PA, RPA, and CXPA suggests that these proteins are not involved in progression, recurrence, or malignant transformation of PA.

MiR-455-3p, miR-150 and miR-375 are aberrantly expressed in salivary gland adenoid cystic carcinoma and polymorphous adenocarcinoma.

BACKGROUND: Adenoid cystic carcinoma (AdCC) and polymorphous adenocarcinoma (PAC) are included among the most common salivary gland cancers. They share clinical and histological characteristics, making their diagnosis challenging in specific cases. MicroRNAs (miRNA) are short, non-coding RNA sequences of 19-25 nucleotides in length that are involved in post-transcriptional protein expression. They have been shown to play important roles in neoplastic and non-neoplastic processes and have been suggested as diagnostic and prognostic markers. METHODS: This study, using quantitative RT-PCR, investigated miR-150, miR-455-3p and miR-375 expression, in order to identify a possible molecular distinction between AdCC and PAC. RESULTS: miRNA-150 and miRNA-375 expression was significantly decreased in AdCC and PAC compared with salivary gland tissue controls, whilst miRNA-455-3p showed significantly increased expression in AdCC when compared to PAC, (P < 0.05). miR-150, miR-357 and miR-455-3p expression in AdCC, PAC and control was not associated with age, gender nor with anatomic site (major and minor salivary glands) (P > 0.05). CONCLUSION: MiR-455-3p could be used as a complimentary tool in the diagnosis of challenging AdCC cases.

The Challenging Diagnosis of Primordial Odontogenic Tumor.

Primordial odontogenic tumor (POT) is a benign mixed odontogenic tumor comprised of a loose connective tissue with a similar morphology with dental papilla and exhibiting in its periphery the presence of a columnar epithelium. POT occurs in young patients and typically is associated with an unerupted tooth, with the mandible being the main anatomic site of occurrence. The present manuscript is aimed at describing a new case of POT and reviewing the main biologic findings related to this odontogenic tumor.

Histologic Evaluation of Leucocyte- and Platelet-Rich Fibrin in the Inflammatory Process and Repair of Noncritical Bone Defects in the Calvaria of Rats.

PURPOSE: This study aimed to evaluate the effects of leucocyte- and platelet-rich fibrin (L-PRF) on the inflammatory process, tissue repair, and expression of vascular endothelial growth factor (VEGF) on bone defects in the calvaria of rats. MATERIALS AND METHODS: L-PRF was obtained from three animals submitted to cardiac puncture to prepare the membranes. Two noncritical defects with a diameter of 2 mm were created in the calvaria of 15 Wistar rats. The defects on the right side were filled with a blood clot (CTRL) and the left side with L-PRF. After 5, 15, and 30 days, the animals were euthanized and the specimens processed for histologic, histomorphometric, and immunohistochemical analyses. In order to measure the intensity of the inflammatory infiltrate and VEGF expression, scores were assigned from 0 to 3, with 0 being no expression, 1 discrete (up to 25%), 2 moderate (between 25% and 50%), and 3 intense (> 50%) expression. The area of bone neoformation at the edges of the defects was also quantified. RESULTS: A less intense inflammatory infiltrate was observed in the defects filled with L-PRF compared with CTRL at all times analyzed (P < .05). At 5 days, no bone neoformation was observed in any of the groups evaluated. After 15 and 30 days, greater bone neoformation was observed in the group treated with L-PRF compared with the CTRL group (P < .05). At 15 days, 3,871.8 (1,070.15) µm2 were recorded for the CTRL and 49,978.5 (14,360.7) µm2 in the L-PRF. At 30 days, 62,284.5 (3,579.5) µm2 were observed in the CTRL and 154,076.6 (31,464.9) µm2 in the L-PRF. At all evaluated times, a lower inflammatory infiltrate was observed in the group treated with L-PRF compared with the CTRL. VEGF expression was observed in the initial phase and throughout the tissue repair process in both groups. At 5 days, there was no difference in VEGF expression between the groups. VEGF was present at the initial phase and throughout the tissue repair process in both groups. In the L-PRF group, a decrease in VEGF expression was observed at 15 and 30 days compared with the CTRL group. CONCLUSION: L-PRF had a positive effect on the regenerative process of bony defects, with a reduced inflammatory response and greater bone neoformation.

Microvessel density and cell proliferation in juvenile ossifying fibroma: A comparative study with central ossifying fibroma.

Considered as an aggressive counterpart of central ossifying fibroma (OF), juvenile ossifying fibroma (JOF) is a benign fibro-osseous neoplasm characterized by an unpredictable destructive behavior, elevated morbidity, mutilating treatment and high potential for local recurrences. The aim of this study is to compare the analysis for cell proliferation and vascular markers between JOF and OF. Cell proliferation index was measured by Ki-67 and Mcm-2 expression and microvessel density (MVD) was obtained by the immunoexpression of CD34/CD105. We observed a reduced expression of vascular markers, where MVD for CD34 was significantly higher in JOF than in OF (p = 0.009), but no statistical difference was found for CD105. JOF and OF showed low expression for Ki-67 and Mcm-2 and no difference was noted between both, suggesting that other mechanisms such as anti-apoptotic and/or pro-autophagic pathways or even increased expression of matrix metalloproteinases may be responsible for the aggressiveness of JOF.

Dermal vasculature and melanocytic proliferation index in photodamaged skin in the assessment of lateral margins of lentigo maligna and lentigo maligna melanoma.

Lentigo maligna (LM) is the most common subtype of melanoma on the face. When it invades the dermis it is called lentigo maligna melanoma (LMM). Its histological delimitation is controversial due to subjectivity. Analysis of peritumoral vasculature and proliferation index of melanocytes may help to differentiate tumor areas from tumor-free areas, as neoplasia-induced angiogenesis in such scenarios, as well as the higher proliferation index of melanocytes in melanomas, are well established. This work compares the peritumoral vasculature and melanocyte proliferation index of LM and LMM with that of adjacent non-neoplastic skin and sun-damaged skin (control). Forty-three resection cases of LM and LMM were selected retrospectively. Immunohistochemistry was performed for anti-CD31 and anti-CD105 to assess vascularization. Melanocyte proliferation index double labeling was performed using the anti-Melan-A and anti-Ki-67. The Chalkley optical grid was used to quantify blood vessel hotspots. Doubly labeled cells with anti-Melan-A and anti-Ki-67 were counted at tumor, free margin, and control skin. Microvasculature quantification under the melanomas, for both CD31 and CD105, was greater than at the margins of the same specimens (P < 0.0001; P = 0.0001) and greater than control skin (P = 0.0016; P = 0.0027), with higher density for CD31 than CD105. The mean number of double-labeled proliferating melanocytes at the melanoma periphery was greater than at the adjacent free skin and control skin (P = 0.0011). The control skin samples showed the highest CD31-positive vasculature in the head and neck region, with a positive correlation between melanocytic proliferation index and vasculature. The presence of neovascularization (CD105) and proliferating melanocytes (Ki67+/Melan-A+) are suspicious findings for LM/LMM, helping to outline, diagnose, and evaluate tumor margins.