c-Jun expression increased according to the degree of oral dysplasia, with the greatest expression found in OSCC. c-Fos expression was intense in normal mucosa, reduced in mild dysplasia and high in moderate to severe dysplasia and in OSCCs. Cyclin D1 was expressed in only a few cases of moderate to severe dysplasia and in most of the OSCCs. Statistical analysis showed a correlation between the three proteins and the degree of epithelial alteration. The present results indicate a possible role of c-Jun and c-Fos in malignant transformation of oral mucosa.

The most frequent lesion was mucocele, and this result is in agreement with the literature. There was a significant difference between the study paediatric and adult populations. The variations in distribution of lesions observed between the several studies were probably due to cultural differences between geographic areas but also to differing elements of the study design.

BackgroundOdontogenic tumors (OTs) are rare lesions, exclusive of the jaws, that are derived from epithelial and/or ectomesenchymal elements of the tooth-forming apparatus. Their biological behavior is heterogeneous, including hamartomatous tissue proliferation, benign nonaggressive and aggressive neoplasms, and malignant tumors with metastatic capacity. The aim of this study was to describe the relative frequency of odontogenic tumors in a Brazilian population. In addition, a review of the literature identified studies on odontogenic tumors that follow the 2005 World Health Organization.Material and MethodsA total of 376 cases of odontogenic tumors from an oral pathology service were reviewed about age, gender, anatomic site and histologic diagnosis.ResultsKeratocystic odontogenic tumors (31.6%) were the most common, followed by ameloblastoma (28.5%), and odontoma (22.6%). The mean age was 32.2 years, and more than half the patients (52.1%) were in the second and third decades of life. The male to female ratio was 1:1.37, with a maxilla to mandible ratio of 1:2.08.ConclusionsThe variation in relative frequency of tumors observed among the several series, including the present study, is probably due in part to cultural differences between geographic areas but also to the study design. Key words:Pathology, epidemiology, odontogenic tumors.

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OBJECTIVE: To evaluate the discrepancy index between the clinical and histological diagnosis and the prevalence of epithelial dysplasia and carcinoma in 45 patients with potentially malignant epithelial oral lesions (PMEL).PATIENTS AND METHODS: We submitted 45 patients with PMEL to clinical examination and obtained a biopsy from each. The results of histological diagnosis were compared to the clinical diagnosis. RESULTS: Clinical diagnosis showed that the most common PMEL was leukoplakia followed by lichen planus and by actinic cheilitis associated with leukoplakia. The most common site was the buccal mucosa. Histological diagnosis revealed that 46.7% of the PMEL were lichen planus. The discrepancy index between clinical and histological diagnosis was 24.4%. The higher discrepancy index occurred among leukoplakias. The prevalence of epithelial dysplasia and carcinoma was 17.8%. CONCLUSIONS: We conclude that all PMEL should be submitted to a microscopic analysis because the discrepancy between clinical and histological diagnosis was present in a quarter of these lesionS. Otherwise, the epithelial dysplasia and carcinoma were more frequent in the leukoplakias.