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.

Effect of Hyaluronic Acid and Poly-L-Lactic Acid Dermal Fillers on Collagen Synthesis: An in vitro and in vivo Study.

PURPOSE: Skin ageing is marked by structural and functional changes in epidermis and dermis, which result clinically in wrinkles, loss of elasticity, and rough-textured appearance. In this context, different dermal fillers have been used to overcome these negative effects associated with skin ageing, such as hyaluronic acid (HA) and poly-L-lactic acid (PLLA). Despite their low immunogenicity, these materials can cause an inflammatory reaction after application. MATERIALS AND METHODS: Considering high demand of HA and PLLA as filler material, this study aimed to evaluate their in vitro and in vivo effects. For the in vitro study, human dermal fibroblast cell cultures were supplemented with HA or PLLA for 24, 48, and 72 h. The following parameters were assayed: 1) cell proliferation, 2) cell viability, and 3) quantification of type I collagen by ELISA. For the in vivo study, HA or PLLA was injected in the dermis of Wistar rats and the tissues were collected after 15, 30, and 60 days for histologic evaluation and for quantification of type I collagen by Western blotting. The quantitative data were statistically analyzed using an ANOVA two-way. The significance level was set at 5%. RESULTS: At 72 h, high cell proliferation was observed for HA compared to control (p<0.05). Cultures exposed to PLLA exhibited a reduction in both cell proliferation and viability compared to control in all time points (p<0.05). Type I collagen expression was greater in cultures exposed to HA or PLLA compared to control (p<0.05). Histologic analysis showed the presence of multinucleated cells only in the PLLA group in all experimental time points. Western blotting analysis revealed high content of type I collagen in HA compared to PLLA (p<0.05). CONCLUSION: The present study addresses a potentially unfavorable effect of dermal PLLA filler on the fibroblast phenotype, with possible clinical complications, unlike HA.

Microvesicles derived from squamous cell carcinoma induce cell death, autophagy, and invasion of benign myoepithelial cells.

BACKGROUND: There has been great interest recently in the mechanisms of cell-to-cell communication through microvesicles (MV). These structures are produced by many different cell types and can modulate cellular activity by induction of epigenetic alterations. These vesicles may promote tumor mass increase either by stimulating cell proliferation via growth factors or by inhibiting apoptosis, which reinforces the role of such vesicles as important modulators of tumor progression. METHODS: The present in vitro study aimed to characterize MV derived from malignant neoplastic epithelial cell cultures (EP) and their effect on the expression of apoptosis/autophagy and invasion related genes of benign myoepithelial (Myo) cell cultures. RESULTS: The results revealed round structures with a mean size of 153.6 (±0.2) nm, with typical MV morphology. CD63 quantification indicated that EP cell culture at 70%-80% confluence secreted 3.088 × 108 MV/mL. Overall, Myo exposed to MVs derived from EP showed both up- and downregulation of tumorigenesis promoting genes. MVs from EP cells promoted cell death of Myo cells and positively modulate BAX, SURVIVIN, LC3B, MMP-2, and MMP-9 expression. Furthermore, an increasing of MMP-2 and MMP-9 secretion by Myo was observed after MV exposure. CONCLUSIONS: These findings suggest that MVs from EP modulate autophagy of Myo cells, which may, in part, explain the disappearance of these cells in in situ areas of invasive carcinoma ex-pleomorphic adenoma. Additionally, the overexpression of MMPs contributes to the development of an invasive phenotype of Myo cells, which could favor the dissolution of the basement membrane during tumorigenesis process.

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.

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.

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.

Benign odontogenic ghost cell lesions revisited and new considerations on dysplastic dentin.

OBJECTIVES: This study aimed to revisit benign odontogenic ghost cell lesions (BOGCL) by hematoxylin and eosin staining and immunohistochemistry. MATERIALS AND METHODS: Thirty cases of calcifying odontogenic cyst (COC) and 6 cases of dentinogenic ghost cell tumor (DGCT) were selected for histopathological and immunohistochemical analysis. Sections stained for cytokeratin (K) 14, K-19, amelogenin, collagen type 1 (COL-1), and dentin matrix acidic phosphoprotein 1 (DMP-1) were evaluated using qualitative analysis. Sections stained for Ki-67 and minichromosome maintenance protein-2 (MCM-2) were evaluated using semi-quantitative analysis. RESULTS: A morphologic overlap was noticed in all BOGCL. Moreover, no differences were detected in the expression of K-14 and K-19. The expression of proliferative markers Ki-67 and MCM-2 was similar between cystic and tumor lesions (p > .05). The presence of COL-1 and absence of amelogenin in the so-called dysplastic dentin, associated with its histologic pattern, suggest that this is in fact an enameloid-like tissue. CONCLUSIONS: The dysplastic dentin should be considered an enameloid-like tissue in these lesions. CLINICAL RELEVANCE: The similarity in histology, protein expression, and proliferative marker indices between COC and DGCT suggest that they are a sole entity and likely represent types of the same neoplasia.

Role of apoptotic, autophagic and senescence pathways in minor salivary gland adenoid cystic carcinoma.

BACKGROUND: Adenoid cystic carcinoma (ACC) is a salivary gland malignancy with poor long-term survival, which warrants studies aimed at clarifying the pathogenesis of this disease in order to widen the scope of therapeutic options currently available. Alterations in regulatory mechanisms relating to vascular support, cell death and autophagy are important pathways for tumor growth in cancer. Thus, the present study aimed to access vascular supply, apoptosis, autophagy and cell senescence in ACC of minor salivary glands. METHODS: We analyzed 25 cases of minor salivary gland ACC by immunohistochemistry using anti-CD34, anti-CD105, anti-D2-40, anti-Bax, anti-Bcl-2, anti-Beclin-1, anti-LC3B, anti-p21 and anti-p16. RESULTS: Microvessel density was low and based on anti-CD34, anti-CD105 and anti-D2-40 immunostaining. There was positivity for anti-CD34, anti-Bcl-2, anti-Beclin, anti-LC3B and anti-p21 and a positive correlation between Bcl-2 and Beclin (p = 0.014). CONCLUSIONS: Our results showed that ACC does not depend on neo-angiogenesis and is probably associated to anti-apoptotic, autophagic and anti-senescence events.

Comparison of p63/p40 Expression With Myoepithelial Markers in Minor Salivary Gland Tumors.

The present study aimed to compare the expression of p63/p40 with smooth muscle actin (SMA) and vimentin (VIM) by myoepithelial cells in minor salivary gland tumors. Fifty-two formalin-fixed paraffin-embedded samples of minor salivary gland tumors derived from intercalated duct (pleomorphic adenoma [PA], adenoid cystic carcinoma [ACC], epithelial-myoepithelial carcinoma [EMC], polymorphous adenocarcinoma [PAC], and secretory carcinoma [SC]) and 3 samples of minor salivary gland tumors derived from excretory duct (mucoepidermoid carcinoma [MEC]) were evaluated by means of immunohistochemistry. The data were analyzed qualitatively. The results indicated that p63 and p40 expression were detected in myoepithelial cells present in PA, ACC, and EMC. However, both proteins were also observed in squamous areas of PA and all cases of MEC. SMA were noticed in some myoepithelial cells of PA, ACC, and EMC. Expression of SMA was negative in the other salivary gland tumors evaluated. VIM was constantly expressed by myoepithelial cells in PA, ACC, and EMC. VIM was also observed in cells of PAC and SC, but not in squamous areas of PA and MEC. In conclusion, p63 expression is almost comparable with VIM in detecting myoepithelial cells, an immunolabeling pattern not followed by p40, and consequently, caution has to be taken during the interpretation of salivary gland tumor exhibiting an p63/p40 phenotype in order to avoid a misdiagnosis.

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.