Estudo histopatológico das displasias epiteliais em lesões inflamatórias crônicas da cavidade oral

Abstract

Introduction: Chronic inflammation plays an important role on the transformation and tumor progression during oral carcinogenesis. There is a great number of chronic inflammatory lesions (CIL) in the oral cavity which are related to dysplastic processes of the epithelium, immune response and changes on the collagen deposition. Objectives: To investigate the presence of dysplasia and to histologically grade them in the CIL of traumatic cause, as well as toaccessthe density of mast cells and different types of collagen fibers in cases of epithelial dysplasias and oral squamous cell carcinomas (OSCC). Material and Method: Initially, 183 CIL cases were evaluated as to the presence of dysplasia and also classified according to its degree of epithelial dysplasia. Among those lesions, 45 CIL cases were selected and divided into two groups: group 1 (15 cases of mild dysplasia), group 2 (15 cases of moderate/severe dysplasia). The control group was composed by 15 cases of OSCC.They were stained with toluidine blue in order to quantify the mast cells and picrosirius red to semi-quantify the collagen type fibers. Results: The mast cells were detected in all groups presenting a mean of 6,76 cells/mm2, 10.82 cells/mm2 and 19.18 cells/mm2 in the control, group 1and 2 respectively. Regarding the collagen fibers, type III was more prevalent on groups 2 and control while type I fibers were more abundant on group 1. Conclusion: Oral chronic inflammatory lesions showed dysplastic changes in most analyzed cases. The results suggests an active participation of mast cells in the stage of tumor transformation, since it was detected a higher density onthe dysplasia cases when compared to the OSCC cases. Nevertheless, the gradual change of collagen type fibers indicates that collagenproducing cells become altered during the stages of dysplasia (tumor transformation).