Transcriptional profiles of SHH pathway genes in keratocystic odontogenic tumor and ameloblastoma.

BACKGROUND: Sonic hedgehog (SHH) pathway activation has been identified as a key factor in the development of many types of tumors, including odontogenic tumors. Our study examined the expression of genes in the SHH pathway to characterize their roles in the pathogenesis of keratocystic odontogenic tumors (KOT) and ameloblastomas (AB). METHODS: We quantified the expression of SHH, SMO, PTCH1, SUFU, GLI1, CCND1, and BCL2 genes by qPCR in a total of 23 KOT, 11 AB, and three non-neoplastic oral mucosa (NNM). We also measured the expression of proteins related to this pathway (CCND1 and BCL2) by immunohistochemistry. RESULTS: We observed overexpression of SMO, PTCH1, GLI1, and CCND1 genes in both KOT (23/23) and AB (11/11). However, we did not detect expression of the SHH gene in 21/23 KOT and 10/11 AB tumors. Low levels of the SUFU gene were expressed in KOT (P = 0.0199) and AB (P = 0.0127) relative to the NNM. Recurrent KOT exhibited high levels of SMO (P = 0.035), PTCH1 (P = 0.048), CCND1 (P = 0.048), and BCL2 (P = 0.045) transcripts. Using immunolabeling of CCND1, we observed no statistical difference between primary and recurrent KOT (P = 0.8815), sporadic and NBCCS-KOT (P = 0.7688), and unicystic and solid AB (P = 0.7521). CONCLUSIONS: Overexpression of upstream (PTCH1 and SMO) and downstream (GLI1, CCND1 and BCL2) genes in the SHH pathway leads to the constitutive activation of this pathway in KOT and AB and may suggest a mechanism for the development of these types of tumors.

Density of mast cells and microvessels in minor salivary gland tumors.

The aim of this study was to investigate the density of mast cells and microvessels in minor salivary gland tumors. Forty-one cases of minor salivary gland tumors (pleomorphic adenoma, n = 10; adenoid cystic carcinoma, n = 11; mucoepidermoid carcinoma, n = 10; and polymorphous low-grade adenocarcinoma) were investigated using immunohistochemistry for mast cell tryptase and von-Willebrand factor. Density of mast cells was higher in mucoepidermoid carcinoma; however, no differences in the number of these cells were observed between the different types of tumors (p > 0.05). The number of mast cells was higher in periparenchymal areas in all tumors, but the difference was not significant (p > 0.05). Mucoepidermoid carcinoma showed the largest number of periparenchymal mast cells, whereas pleomorphic adenomas showed the smallest number of intraparenchymal mast cells (p > 0.05). The highest microvessel density was observed in mucoepidermoid carcinomas, being this difference statistically significant when mucoepidermoid carcinoma was compared to pleomorphic adenoma (p = 0.0034) and polymorphous low-grade adenocarcinoma (p = 0.004). Microvessel density was significantly higher in adenoid cystic carcinoma when compared to pleomorphic adenoma (p = 0.0406) and polymorphous low-grade adenocarcinoma (p = 0.0123). Comparison of mast cells and microvessel densities showed no significant difference between tumors. A quantitative difference in mast cells and microvessels was observed, particularly in mucoepidermoid carcinoma, a finding supporting the aggressive behavior of malignant salivary gland tumors without myoepithelial differentiation. Further studies are needed to determine the role of mast cells in angiogenesis, as well as in the development and biological behavior of these tumors.

CD1a-positive Langerhans cells and their relationship with E-cadherin in ameloblastomas and keratocystic odontogenic tumors.

BACKGROUND: Ameloblastomas and keratocystic odontogenic tumors (KOTs) are lesions that are characterized by locally invasive growth and cause extensive bone destruction. In addition, it is known that E-cadherin influences the adhesion of Langerhans cells (LCs) to keratinocytes. OBJECTIVE AND METHODS: The aim of this study was to investigate, using immunohistochemistry, the distribution of CD1a-positive cells in ameloblastomas and KOTs and their relationship with E-cadherin, in comparison to calcifying cystic odontogenic tumor (CCOT). RESULTS: The CD1a-positive LCs were observed in 11 ameloblastomas and KOTs. All of the cases of CCOT showed CD1a-positive LCs and a significant difference was found when this tumor was compared with ameloblastomas (P < 0.05, Mann-Whitney test). A statistically significant difference was also noted when comparing CD1a-positive LCs between CCOTs and KOTs (P < 0.05, Mann-Whitney test). Lower expression of E-cadherin in ameloblastomas (AMs) in relation to KOTs and CCOTs (P < 0.05, Fisher test) was observed. There was no correlation between E-cadherin and CD1a-positive LCs between all odontogenic tumors that were studied (P > 0.05, Spearman test). CONCLUSION: A quantitative difference of CD1a-positive cells between AMs and KOTs in comparison to CCOTs was observed. This permits to speculate that a depletion of CD1a-positive LCs might influence the local invasiveness of ameloblastomas and KOTs. Furthermore, it is suggested that E-cadherin mediates cell adhesion in these tumors.

Effects of imiquimod and low-intensity laser (λ660 nm) in chemically induced oral carcinomas in hamster buccal pouch mucosa.

Squamous cell carcinoma (SCC) is the most common neoplasm of the oral cavity. It is aggressive, highly proliferative, and metastatic. This study aimed to evaluate the effect of LLLT and imiquimod on DMBA chemically induced lesions on the oral mucosa of hamsters. SCCs were induced on 25 hamsters. Animals of G1 (control 1) were killed and the presence of tumors confirmed; G2 (control 2) suffered no interventions for additional 4 weeks; animals of G3 (laser treatment) were irradiated (λ660 nm, 50 mW, CW, Ø=3 mm, 0.07 cm(2), 714.2 mW/cm(2), 133 s, 95 J/cm(2), 6.65 J) at every other day for 4 weeks; animals of G4 (imiquimod treatment) received 5 % imiquimod three times a week for 4 weeks; and animals of G5 (imiquimod and laser treatment) received both treatments for the same period. Samples were taken and underwent histological analysis by light microscopy and were investigated using immunohistochemistry for S-100(+) dendritic cells. In G1, G2, and G3, the evaluations showed malignant tumors and the absence of S-100(+) dendritic cells in the tumor stroma. In G4, 60 % of the animals had no malignant tumors, and S-100(+) dendritic cells were present in the stroma of the tumors as well as dysplasia. In G5, 40 % of the animals presented SCC, with scarce or no S-100(+) dendritic cells. The imiquimod treatment played a direct effect on SCC, demonstrated by the increased number of S-100(+) dendritic cells, which could suggest an important role of immune surveillance against neoplastic proliferation. Furthermore, its association with laser needs to be further investigated.

Distribution of mast cells in benign odontogenic tumors.

The aim of this study was to investigate the presence of mast cells in a series of odontogenic tumors. Forty-five cases of odontogenic tumors were investigated using immunohistochemistry for mast cell triptase, and differences between groups were statistically evaluated. Mast cells were present in 96% of odontogenic tumors. Mast cells present in solid ameloblastoma were observed in the tumor stroma surrounding more solid and follicular epithelial islands, with or without squamous metaplasia. The odontogenic mixoma showed few mast cells. In odontogenic tumors with a cystic structure, the mast cells were distributed throughout all areas of the lesions, mainly in keratocystic odontogenic tumor. In addition, the total density of mast cells between all odontogenic tumors showed no significant difference (p > 0.05). A greater mast cells distribution was found in keratocystic odontogenic tumor in relation to adenomatoid odontogenic tumor (p < 0.01), and when the unicystic ameloblastoma and keratocistic odontogenic tumor were compared to the odontogenic myxoma (p < 0.05). Syndrome keratocystic odontogenic tumor showed a higher mean of mast cells when compared with the other tumors of the sample. Mast cells values presented by syndrome keratocystic odontogenic tumor were significantly greater than those of the sporadic keratocystic odontogenic tumor that were not associated with the syndrome (p = 0.03). Mast cells are probably one of the major components of the stromal scaffold in odontogenic tumors. We found significant differences of mast cells between syndrome nonsyndrome keratocystic odontogenic tumors, although their distribution did not seem to have any influence on the biologic behavior of benign odontogenic tumors.

Immunohistochemical assessment of CD1a-positive Langerhans cells and their relationship with E-cadherin in minor salivary gland tumors.

OBJECTIVE: The aim of this study was to investigate the presence of CD1a-positive Langerhans cells and their relationship with E-cadherin in minor salivary gland tumors. METHODS: Twenty-seven minor salivary gland tumors were investigated using immunohistochemistry for CD1a and E-cadherin. RESULTS: A significant difference regarding the mean density of CD1a-positive Langerhans cells was observed between pleomorphic adenomas and malignant tumors studied (P = 0.001). No CD1a-positive cells were detected in most cases (n = 5) of cystic adenoid carcinomas. CD1a-positive cells were detected in one mucoepidermoid carcinoma case, and six low-grade polymorphous adenocarcinomas cases. Comparison of the mean density of CD1a-positive cells between the three malignant tumors showed no significant difference (P = 0.127). No significant difference was observed in the presence of E-cadherin between tumors (P = 0.73), but it was detected in 24 cases. CONCLUSIONS: The lack of CD1a-positive in malignant salivary gland tumors facilitates the neoplastic development and suggests that these cells might be useful as auxiliary diagnostic and prognostic tool in minor salivary gland tumors. Furthermore, it is suggested that E-cadherin mediates cell adhesion in these tumors although we did not demonstrate significance.

Gingival cyst of the adult: a case report and immunohistochemical investigation.

A 42-year-old woman had a sessile swelling that involved the maxillary gingiva corresponding to the right canine and premolar area. Clinical examination showed a painless small nodule (10 mm in diameter) located between the right maxillary canine and premolar. The lesion was vesicular, sessile, and slightly compressible on palpation. Microscopic examination of the lesion (following an excisional biopsy) showed cystic spaces covered by an epithelium lining that consisted of cuboidal and squamoid cells intermingled with clear cells. These morphologic findings were consistent with gingival cyst of the adult. Immunohistochemical technique against cytokeratins revealed that the epithelial cells were positive for cytokeratins No. 7, 8, 13, 14, and 19. Two years after removal, no recurrence was reported.

Expression of Ki-67, p53 and p63 proteins in keratocyst odontogenic tumours: an immunohistochemical study.

AIM: To investigate the immunohistochemical expression of Ki-67, p53 and p63 in Keratocyst Odontogenic Tumours (KOTs) in order to contribute to the biological profile of this tumor. METHODS: Immunohistochemical technique was performed using the EnVision System in 37 cases of KOTs. RESULTS: Ki-67- and p53-immunostained cells were mainly located in the suprabasal layers. p63-positive cells were found throughout the lining cystic epithelium. No difference in the immunostaining for these proteins was observed between primary and recurrent KOTs (Ki-67: P = 0.5591; p53: P = 0.9847; p63: P = 0.9127), or between KOTs associated with Nevoid Basal Cell Carcinoma Syndrome (NBCCS) and sporadic KOTs (Ki-67: P = 0.7013; p53: P = 0.3197; p63: P = 0.2427). CONCLUSIONS: It is possible that biological behavior of KOTs may be related to suprabasal proliferative compartment in the cystic epithelium as observed by high levels of Ki-67, p53 and p63. In addition, p63 immunostaining may represent immaturity of keratinocytes in KOTs, and suggests that this protein may participate in the regulation of epithelial cell differentiation. Taken together, these data may favor tumorigenesis on KOTs.

Immunohistochemical detection of Langerhans cells in dental granulomas and radicular cysts.

OBJECTIVE: Dental granulomas (DGs) and radicular cysts (RCs) are chronic periapical lesions frequently involving the jaws. Langerhans cells (LCs) are dendritic cells responsible for the presentation of antigens to T lymphocytes. This study examined the expression of LCs in DG and RCs by immunohistochemical staining. STUDY DESIGN: Eighteen cases of DGs and 26 cases of RCs were analyzed using anti-CD1a marker. RESULTS: CD1a-labeled LCs were observed in 11.1% of DGs and in 69.2% of RCs, showing a significant correlation (P < 0.0001; Fisher's test). In DGs, LCs were only observed in granulation tissue, showing discrete immunostaining density. In RCs, LCs exhibited both a round and a dendritic shape in all epithelial layers. Although a correlation was observed between immunostaining density and epithelial thickness, as well as between immunostaining and inflammatory intensity, the differences were not significant in radicular cysts. CONCLUSION: Langerhans cells provide important insight into the immunopathogenesis of chronic periapical lesions.

Tumor-infiltrating macrophage and microvessel density in oral squamous cell carcinoma.

Tumor-associated macrophages (TAM) are the main cellular component in stroma of many tumors and participate in tumor angiogenesis. The aim of present study was to compare the microvascular density (MVD) and infiltrating macrophage density (IMD) in oral squamous cell carcinomas (OSCCs) with different histological grades. A histomorphometric analysis was performed after immunohistochemistry using antibodies such as von-Willebrand factor and CD68. A significant difference in MVD was found between well and moderately differentiated OSCCs (p<0.05). TAM were largely present in all studied tumors and the IMD was not different among OSCCs with different histological grades (p=0.381). Significant correlation between MVD and IMD was not observed (p=0.870). In conclusion, these results suggest that TAM and angiogenesis have an influence at different histological grades of OSCC. However, the lack of correlation between MVD and IMD could suggest that angiogenesis does not depend on the number of macrophages present in OSCC, but their predominant phenotype. Further studies involving distinct phenotypes of macrophages should be done to better understand the influence of TAM on the tumor angiogenesis.

Keratocystic odontogenic tumour: an experience in the Northeast of Brazil.

INTRODUCTION: Keratocystic odontogenic tumours raise particular interest, because of their high recurrence rate and association with nevoid basal cell carcinoma syndrome. OBJECTIVE: To analyze the clinical and histopathological features of all cases diagnosed as keratocystic odontogenic tumour in a Brazilian population. METHODS: A total of 64 keratocystic odontogenic tumours, arising in forty-six patients, were evaluated using the following parameters: association with nevoid basal cell carcinoma syndrome, gender, age at first diagnosis, race, anatomical location, symptoms, radiographic features, history of recurrence, association with teeth, and treatment. RESULTS: Keratocystic odontogenic tumours were more frequent among women than men (1:0.84). The mean patient age was 31.5 years (SD: +/- 16.6). Ten tumours (16.4%) involved the maxilla and 51 (83.6%) the mandible. Swelling (n = 12; 46.1%), followed by pain and swelling (n = 4; 15.3%), were most common clinical manifestations. A unilocular radiotransparency with well-defined margins was the main radiographic finding (n = 29; 87.8%). A significant association was observed between the multilocular radiographic pattern and recurrence (p < 0.05, Fisher's Test). Sixty-one (95.3%) tumours were treated by surgical enucleation followed by bone curettage, and the recurrence rate was 13% (n = 6). This study showed that the keratocystic odontogenic tumours relapsed within a mean period of 25-36 months. CONCLUSION: Despite the results of this study being similar to previous reports found in the literature, it provides an important insight about keratocystic odontogenic tumours in a Brazilian population.

Histopathological study of radicular cysts diagnosed in a Brazilian population.

The aim of this study was to investigate the histopathological features of radicular cysts (RCs) diagnosed in a Brazilian population. Seventy-three cases of RCs, from a total of 1480 biopsies diagnosed between 2001 and 2008 at the Laboratory of Oral Surgical Pathology of the Dental School of the Federal University of Bahia were investigated regarding their histopathological features. Morphological results showed that exocytosis (n = 50), spongiosis (n = 40), acanthosis (n = 28), atrophic epithelium (n = 27) and apoptotic bodies (n = 21) were the most common findings. Other morphological findings included: foamy macrophages (n = 10), Russell's bodies (n = 7), cholesterol crystals (n = 7) and glandular-like odontogenic epithelial rests (n = 1). Evidence of exogenous material was seen in 16 samples. It was concluded that the clinical and histopathological findings observed in Brazilian patients were comparable with those described for other populations.

Accumulation of CD1a-positive Langerhans cells and mast cells in actinic cheilitis.

LCs and MCs are known to be directly influenced by UV radiation. This study investigated the presence of Langerhans cells (LCs) and mast cells (MCs) in actinic cheilitis (AC) exhibiting epithelial dysplasia (ED). Using immunohistochemistry for CD1a and mast cell tryptase, LCs and MCs density was assessed in 35 cases of AC with different degrees of ED. LCs were found in 32 cases of AC whereas MCs were found in all cases. There was an increase in LCs density irrespective of degree of ED when the cases were compared to normal lip mucosa (P = 0.04343). No statistical difference in LCs density was observed regarding the different degrees of dysplasia (P > 0.05). Significant difference in MCs density between mild and moderate dysplasia and normal lip mucosa was found (P < 0.05). No significant correlation between LCs and MCs was seen (P = 0.1258). Although no correlation could be established between LCs and MCs and the different degrees of ED; it is possible that the accumulation of LCs plays an immunostimulatory and protective role in the defense against progression of dysplasia. Further studies are necessary to determine the role of MCs in the development of AC.

Altered expression of cytokeratins in primary, recurrent and syndrome keratocystic odontogenic tumors.

Keratocystic odontogenic tumor (KOT) is a benign cystic tumor that affects the jaw bones and may be associated with the nevoid basal cell carcinoma syndrome (NBCCS). Twenty-five cases diagnosed as KOT, including primary and recurrent tumors and those associated with NBCCS, were submitted to immunohistochemical study for analysis of cytokeratins (CKs) 7, 8, 10, 13, 14, 18 and 19. The results showed CK13 immunostained on the intermediate layers and upper cells. CK14 was expressed in all epithelial layers and in those areas where inflammation and subepithelial splits were present; this protein was preserved within the basal cells. CK 18 was expressed mainly in the basal layer, whereas CK19 was expressed mainly on the intermediate and superficial layers. The remaining CKs tested were not immuoreactive. The status of maturation of cytokeratin seems to be altered on KOTs, and this is not distinct when different tumors are compared.

Russell body apical periodontitis: an unusual case report.

Russell bodies (RBs) changes in chronic apical lesions have rarely been reported in the literature. We describe a case of a periapical lesion abundantly and extensively composed of RB. Microscopic examination showed accumulation of plasma cells containing globular, spherical, polygonal, and eosinophilic structures against fibrous connective tissue. Initial diagnostic considerations based on a smaller magnification included hypersecretory plasmocytoma, although there was no evidence of infiltrative growth, mitotic activity, nuclear atypia, or cellular pleomorphism. Then, a panel of immunohistochemical markers was applied and the cells showed positivity with both kappa and lambda chains demonstrating their polyclonal origin. The extensive accumulation of RBs involving the periapical region represents an unreported and significant histologic change, as it was mimicking a malignant neoplasm.

Tumor-Infiltrating Macrophage and Microvessel Density in Oral Squamous Cell Carcinoma

Tumor-associated macrophages (TAM) are the main cellular component in stroma of many tumors and participate in tumor angiogenesis. The aim of present study was to compare the microvascular density (MVD) and infiltrating macrophage density (IMD) in oral squamous cell carcinomas (OSCCs) with different histological grades. A histomorphometric analysis was performed after immunohistochemistry using antibodies such as von-Willebrand factor and CD68. A significant difference in MVD was found between well and moderately differentiated OSCCs (p<0.05). TAM were largely present in all studied tumors and the IMD was not different among OSCCs with different histological grades (p=0.381). Significant correlation between MVD and IMD was not observed (p=0.870). In conclusion, these results suggest that TAM and angiogenesis have an influence at different histological grades of OSCC. However, the lack of correlation between MVD and IMD could suggest that angiogenesis does not depend on the number of macrophages present in OSCC, but their predominant phenotype. Further studies involving distinct phenotypes of macrophages should be done to better understand the influence of TAM on the tumor angiogenesis.

Macrófagos associados a tumores (MAT) representam o componente principal do estroma de muitos tumores, além de participar da angiogênese tumoral. Este estudo comparou a microdensidade vascular (MDV) e densidade de macrófagos infiltrando o tumor (DMIT) em carcinoma escamocelular da boca (CEC) com diferentes graus histológicos de malignidade. Análise histomorfométrica foi empregada após técnica imuno-histoquímica para os anticorpos fator von-Willebrand e CD68. Uma diferença significante entre MDV e carcinomas bem e moderadamente diferenciados foi observada (p<0,05). MAT estavam fortemente presentes em todos os tumores estudados e a DMIT não foi diferente entre os diferentes graus histológicos de malignidade do CEC (p=0,381). Correlação significante entre MDV e DMIT não foi observada (p=0,870). Em conclusão, os resultados desse estudo sugerem a influência de MAT e angiogênese nos diferentes graus histológicos de malignidade do CEC. Entretanto, a ausência de correlação entre MDV e DMIT sugere que a angiogênese não depende do número de macrófagos presentes neste tipo de câncer, mas do fenótipo predominante. Outros estudos devem ser realizados a fim de contribuir para melhor compreensão da participação de MAT na angiogênese tumoral.

Elastin accumulation in actinic cheilitis with different degrees of epithelial dysplasia / Acumulación de elastina en queilitis actínica con diferentes grados de displasia epitelial

The extracellular matrix (ECM) plays an important role in the regulation of biological events such as the development of cell migration, proliferation and differentiation. Chronic sun exposure causes changes present in the ECM of actinic cheilitis (AC), a premalignant lesion of the lower lip which helps to understand the carcinogenesis of the lip. This study aimed to investigate elastin, the main component of solar elastosis alternating current in an attempt to establish the relationship between this protein and ECM in epithelial dysplasia. Paraffin embedded tissue sections of the lesions of 35 cases of AC were analyzed by immunohistochemistry for elastin, and became the association with the degree of epithelial dysplasia and age. Highest scores of elastin (+3) was predominant in 45.7 percent of cases of AC, especially in cases of severe dysplasia (n = 3). When comparing the scores of elastin between the different grades of epithelial dysplasia showed no significant difference (P> 0.05, Kruskal-Wallis). This study was not able to demonstrate the influence of elastin on the severity of epithelial dysplasia in AC. Additional studies on other ECM proteins must be conducted in an attempt to better understand the mechanism of malignant progression of the AC.

La matriz extracelular (MEC) juega un papel importante en la regulación de los eventos biológicos, tales como, el desarrollo de la migración celular, proliferación y diferenciación. La exposición solar crónica provoca cambios presentes en la MRC de la queilitis actínica (QA), una lesión premaligna del labio inferior que contribuye a entender la carcinogénesis del labio. Este estudio tuvo como objetivo investigar la elastina, el componente principal de la elastosis solar en corriente alterna en un intento de establecer la relación entre esta proteína y la MEC en displasia epitelial. Se incluyeron en parafina cortes de tejido de las lesiones de 35 casos de QC fueron analizadas mediante técnicas de inmunohistoquímica para elastina, y se hizo la asociación con los grados de displasia epitelial y la edad. La más alta puntuación de la elastina (+3) fue predominante en el 45,7 por ciento de los casos de QA, especialmente en los casos de displasia severa (n = 3). Al comparar las puntuaciones de elastina entre los diferentes grados de displasia epitelial, no mostró diferencia significativa (P> 0,05, Kruskall-Wallis). Este estudio no fue capaz de demostrar la influencia de la elastina sobre gravedad de la displasia epitelial en QA. Estudios adicionales sobre otras proteínas de la MEC deben llevarse a cabo en un intento por comprender mejor el mecanismo de progresión maligna de la QC.

Histopathological study of radicular cysts diagnosed in a Brazilian population

The aim of this study was to investigate the histopathological features of radicular cysts (RCs) diagnosed in a Brazilian population. Seventy-three cases of RCs, from a total of 1480 biopsies diagnosed between 2001 and 2008 at the Laboratory of Oral Surgical Pathology of the Dental School of the Federal University of Bahia were investigated regarding their histopathological features. Morphological results showed that exocytosis (n=50), spongiosis (n=40), acanthosis (n=28), atrophic epithelium (n=27) and apoptotic bodies (n=21) were the most common findings. Other morphological findings included: foamy macrophages (n=10), Russell’s bodies (n=7), cholesterol crystals (n=7) and glandular-like odontogenic epithelial rests (n=1). Evidence of exogenous material was seen in 16 samples. It was concluded that the clinical and histopathological findings observed in Brazilian patients were comparable with those described for other populations.

O propósito desse estudo foi investigar os aspectos histopatológicos de cistos radiculares diagnosticados em uma população brasileira. Setenta e três casos de cistos radiculares entre 1480 biópsias diagnosticadas na Faculdade de Odontologia da Universidade Federal da Bahia, entre 2001 e 2008, foram investigados, considerando os seus aspectos histopatológicos. Os resultados morfológicos mostraram que os achados mais comuns foram a exocitose (n=50), espongiose (n=40), acantose (n=28), epitélio atrófico (n=27) e células apoptóticas (n=21). Outros achados encontrados incluíram macrófagos espumosos (n=10), corpúsculos de Russell (n=7), imagens negativas de colesterol (n=7) e restos epiteliais odontogênicos semelhantes à tecido glandular (n=1). Material exógeno foi observado em 16 casos. Concluiu-se que os aspectos histopatológicos e clínicos observados foram comparáveis a outros descritos em outras populações.

Density of Langerhans cells in the keratocystic odontogenic tumor / Densidade das células de Langerhans no tumor odontogênico queratocístico

INTRODUCTION: Keratocystic odontogenic tumors (KOTs) are distinct odontogenic lesions commonly affecting the mandible bones. Langerhans cells (LCs) are specialized dendritic cells responsible for the presentation of antigens to T lymphocytes in mucosal and cutaneous surfaces. OBJECTIVE: This study analyzed the immunohistochemical expression of LCs in KOTs. MATERIALS AND METHODS: Fifteen cases of KOTs were studied using the anti-CD1a marker. Results: LCs were observed in all 15 cases analyzed. They were found to be concentrated in areas of cystic epithelial hyperplasia, mainly in those areas presenting higher concentration of inflammatory cells. Furthermore, a significant association between the number of LCs and areas of cystic epithelium presenting hyperplasia (Mann-Whitney test, p = 0.0223) was observed. The shape and location of these cells in KOTs epithelium were variable. CONCLUSION: The lower number of LCs observed on atrophic cystic epithelium of KOTs may be due to decreased epithelial immunosurveillance and this may result in locally aggressive invasiveness.

INTRODUÇÃO: Tumor odontogênico queratocístico (TOQ) é uma lesão odontogênica de caráter distinto que afeta frequentemente ossos maxilares. Células de Langerhans (CLs) são células dendríticas especializadas, responsáveis pela apresentação de antígenos aos linfócitos T nas superfícies cutânea e mucosa. OBJETIVO: Este estudo analisou a expressão imuno-histoquímica das CLs em lesões de TOQ. MATERIAIS E MÉTODOS: Quinze casos de TOQ foram estudados utilizando o marcador anti-CD1a. RESULTADOS: As CLs foram observadas em todos os 15 casos analisados. Essas células estavam concentradas em áreas de hiperplasia do epitélio cístico, especialmente naquelas que apresentavam alta concentração de células inflamatórias. Em adição, foi encontrada associação significativa entre número de CLs e áreas do epitélio cístico que apresentavam hiperplasia (Mann-Whitney test, p = 0.0223). O formato e a localização dessas células no epitélio dos TOQs foram variáveis. CONCLUSÃO: O menor número de CLs encontrado no revestimento cístico atrófico dos TOQs pode ser atribuído à imunovigilância deficiente e isso pode resultar em comportamento biológico localmente agressivo.