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Odontogenic lesions differ in their rate of recurrence and aggressiveness. This study aimed to evaluate the presence of myofibroblasts and mast cells in odontogenic lesions. Sample consisted of 20 cases each of dentigerous cysts, odontogenic keratocysts, and solid ameloblastomas. Histologic sections were submitted to immunohistochemistry using anti-α-smooth muscle actin and anti-tryptase antibodies. Myofibroblasts and mast cells were counted at ×400 magnification in 5 and 10 fields, respectively. Myofibroblasts were more frequent in ameloblastomas (24.41), followed by odontogenic keratocysts (16.21) and dentigerous cysts (11.85; P=.002). Granulated and degranulated mast cells were more frequent in dentigerous cysts (7.88 and 8.96, respectively), followed by odontogenic keratocysts (6.53 and 7.08) and ameloblastomas (5.21 and 1.88). The difference was only significant for degranulated mast cells (P<.05). Analysis of the correlation between myofibroblasts and mast cells (granulated and degranulated) revealed a moderate positive correlation only in ameloblastomas (R=0.621, P=.003). Probably, myofibroblasts are related to the biological behavior of the odontogenic lesions studied, particularly their aggressiveness. On the other hand, mast cells seem to be associated with inflammatory processes, which are more frequent in cystic lesions than in benign neoplasms. In addition, mast cells may induce the differentiation of fibroblasts into myofibroblasts, thus increasing the number of the latter.

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El Ameloblastoma Acantomatoso es una variante histopatológica donde la parte central de las células Epiteliales Odontogénicas sufren una metaplasia escamosa. Este cambio biológico podría darle a esta forma de ameloblastoma características de mayor agresividad y recidiva. El objetivo del presente trabajo fue determinar la expresión de las proteínas p53 y Ki-67 en ameloblastomas acantomatosos. Metodología: 12 especímenes diagnosticados histopatológicamente como ameloblastoma acantomatoso fueron examinados y la expresión de p53 y Ki-67 determinada inmunohistoquímicamente usando los anticuerpos anti-humanos clones DO-7 y MIB-1 respectivamente (DAKO®). La expresión de ambas proteínas fue evaluada mediante microscopio de luz y la intensidad y número de núcleos positivos semicuantificados y analizados mediante estadística descriptiva. Resultados: La expresión de p53 fue observada en el 50% de los casos tanto en las células basales como centrales de las islas tumorales. La expresión de Ki-67 fue observada en el 66,7% de los casos, en su mayoría tanto en las células basales como tumorales y en su totalidad de fuerte intensidad. Conclusiones: La expresión de p53 y Ki-67 en los ameloblastomas acantomatosos sugiere una proliferación celular acelerada y por ende una mayor capacidad de crecimiento. Estas proteínas podrían conformar una herramienta para la selección de tratamientos más radicales en ameloblastomas que las expresen

Acanthomatous Ameloblastoma is a histopathological variant where the central portions of odontogenic epithelial cells undergo squamous metaplasia. This biological change could confer more aggressive features and recurrence to the tumour. The aim of this study was to determine the expression of p53 and Ki-67 in acanthomatous ameloblastoma. Methods: 12 specimens histologically diagnosed as acanthomatous ameloblastomas were examined and the expression of p53 and Ki-67 determined immunohistochemically using anti-human antibody clone DO-7 and MIB-1 respectively (DAKO ®). The expression of both proteins was assessed by light microscopy and the intensity and number of positive cells semi-quantified and analyzed using descriptive statistics. Results: The expression of p53 was observed in 50% of the cases both in the basal cells as tumor central islands. The Ki-67 expression was observed in intensely in 66.7% of cases, mainly on basal cell as central. Conclusions: The expression of p53 and Ki-67 in acanthomatous ameloblastomas suggests accelerated cell proliferation and therefore increased capacity for growth. Expression of these proteins may constitute a tool for prognosis and treatment selection

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Introdução: Os tumores odontogênicos correspondem a menos de 1% dos tumores da cavidade oral, sendo os ameloblastomas bastante freqüentes, com ocorrência na mandíbula em cerca de 80% dos casos. A maior incidência na mandíbula é nos molares, como também na maxila. Objetivo: Avaliar resultados do tratamento de pacientes portadores de ameloblastoma. Pacientes e método: Foram analisados os prontuários de 12 pacientes com ameloblastoma, sendo 10 deles na mandíbula e dois em maxila, no período de 1996 a 2005. A média de idade foi de 37,7 anos com predominância do gênero feminino, com sete casos, sendo 10 pacientes caucasianos. As queixas clínicas predominaram com abaulamento na cavidade oral, alteração de posição e amolecimento dentário. A avaliação pré-operatória constou de exame físico geral e específico, exames radiológicos, exames laboratoriais pré-operatórios e revisão de exame anátomo-patológico. Através de radiografia panorâmica da mandíbula e/ou tomografia computadorizada da cavidade oral, foram analisadas extens??o da lesão e sua relação com dentes e presença de erosão óssea na mandíbula. Resultados: O tratamento foi a ressecção da lesão e reconstrução imediata com enxerto ósseo de crista ilíaca, com exceção de dois pacientes. No pós-operatório, houve dois casos de deiscência da sutura intra-oral e exposição da placa de reconstrução, que obrigou sua retirada e dos enxertos ósseos. Não tivemos caso de recidiva tumoral. Conclusões: Os ameloblastomas ainda apresentam dificuldade em seu diagnóstico precoce, devido à pouca sintomatologia inicial e também por causa de sua raridade. O tratamento preferencial para os tumores mais avançados é a ressecção ampla com reconstrução imediata.

Introduction: Odontogenic tumors correspond to less than 1% of the tumors of the oral cavity and, among them, the ameloblastomas are the most frequent, with 80% of the cases occurring in the jaw, mainly in molar area, what also happens when they appear in the maxilla. Objective: to evaluate the outcome of the treatment in patients with ameloblastoma. Patients and methods: We analyzed the medical charts of 12 patients with ameloblastoma, with 10 cases in the jaw and 2 in the maxilla, during the period from 1996 to 2005. The average age was of 37.7 years-old with 7 cases in women and 10 cases in Caucasian patients. The clinical complaints prevailed with oral cavity swelling and change of the dental position. The preoperative evaluation consisted of general and specific physical examination and radiological examinations (panoramic X ray and/or CT scan). The image exams were employed to analyze the extension of the lesion and its relationship with dental elements and the presence of erosion of the external and internal boards of the jaw. Results: All patients were treated with resection of the lesion and immediate reconstruction with crest iliac bony graft, except for two patients. The postoperative complications were two cases of infection with intraoral suture line dehiscence and exposition of the reconstruction plate and consequent retreat of the plates and bony grafts. Conclusion: The ameloblastomas still present with difficulty in early diagnosis due to the small importance that the patients give for the initial symptoms and also its rarity. The preferential treatment for the most advanced tumors is the wide resection with immediate reconstruction.

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OBJETIVO: O presente trabalho teve por objetivo traçar o perfil das citoqueratinas (CKs) 7, 8, 10, 13, 14, 18 e 19 em ameloblastomas e tumor odontogênico adenomatóide (TOA) visando contribuir para o entendimento da histogênese desses tumores e somar com os resultados já relatados na literatura. MATERIAL E MÉTODO: do arquivo do Laboratório de Anatomia Patológica do Departamento de Odontologia da Universidade Federal do Rio Grande do Norte (UFRN) foi selecionada uma amostra com dez casos de ameloblastomas e oito de TOA para o estudo imuno-histoquímico, utilizando-se anticorpos anti-CKs pelo método da estreptoavidina-biotina. RESULTADOS: Observou-se que nos ameloblastomas a CK 14 esteve presente em todos os casos, enquanto a CK 19 foi observada nas células periféricas (oito casos) e nas centrais (cinco casos). Para os TOA, observou-se imunopositividade para a CK 14 em todos os casos, enquanto a CK 19 esteve marcada predominantemente nas células ductais (seis casos). CONCLUSÃO: As citoqueratinas são expressas de forma variada nos ameloblastomas e nos TOA, os quais preservam CK típicas do germe dental em estágios avançados do desenvolvimento, confirmando sua origem exclusiva a partir do epitélio odontogênico e não se evidenciando CK características do epitélio escamoso.

OBJECTIVES: The aim of the present study was to describe the immunohistochemical expression of cytokeratins (CKs) 7, 8, 10,13, 14, 18 and 19 in the epithelial components of ameloblastomas and adenomatoid odontogenic tumor (AOT). The results were compared and histogenesis discussed. MATERIAL AND METHOD: Specimens of ten ameloblastomas and eight adenomatoid odontogenic tumors were examined by immunohistochemistry using streptavidin-biotin-peroxidase complex method and anti-CKs antibody. The sample was obtained from Department of Oral Pathology, Federal University of Rio Grande do Norte. RESULTS: Immunohistochemical reactivity for CK14 was detected in all cases of ameloblastomas, and the expression of CK19 was diffusely present in peripheral cells (eight cases) and in central cells of five ameloblastomas. In AOTs, immunopositivity for CK14 was detected in all cases, whereas CK 19 was predominantly expressed in ductal cells (six cases). CONCLUSION: The CKs was expressed by several forms in ameloblastomas and AOTs, that have shown typical CKs of dental germ suggesting that these tumors have odontogenic epitheilial differentiation, whereas it has not evinced proper CKs of squamous epithelial.

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