Comparison of the histopathologic features of oral lichen planus and oral lichenoid reactions in patients referred to faculty of dentistry, Tabriz university of medical sciences (from the year 1383 to 1400)

Abstract

Introduction: Oral lichen planus (OLP) and oral lichenoid reaction (OLR) have similar clinical and histopathological features, while these two lesions differ from each other both in terms of the required treatment and in terms of the potential of turning into malignancy. Considering that different results have been reported in studies regarding the histopathological difference between these two lesions, the present study aimed to compare the histopathological characteristics of oral lichen planus and oral lichenoid reactions in patients referred to Tabriz Dental Faculty. Materials and Methods: The present study is a cross-sectional study. Samples related to oral lichen planus and oral lichenoid reactions were obtained from the archives of the Department of Oral and Maxillofacial Pathology, Faculty of Dentistry, Tabriz University of Medical Sciences. All available samples; from the years 1383 to 1400; were included in the study. The slides stained with hematoxylin-eosin were examined by two pathologists. Then, all the slides were examined and compared using a light microscope in terms of 14 histopathological features that can be observed in lichen planus or lichenoid reactions. The data obtained from the study were reported by descriptive statistical methods (percentage and Frequency, ...). Chi-square test and SPSS25 software were used to compare between 2 groups in terms of histopathological characteristics and the significance level p<0.05 was considered.

Results: In the samples of lichen planus, the most lesion site was related to the buccal mucosa with 50 cases (63%), and the least was related to the lip and palate each with 3 cases (4%) and in the lichenoid reaction samples, the most lesion site was related to buccal mucosa with 16 cases (44%) and the lowest was related to gums with 4 cases (11%). Hydropic degeneration of the basal cell layer, was observed in all samples of the 2 groups of lichen planus and lichenoid reaction. In terms of presence of vascularity in the subepithelial area, band-like infiltration of lymphocytes, hyperkeratosis (parakeratosis-orthokeratosis) and hypergranulosis, between the 2 groups the difference was significant and were observed more in lichen planus than lichenoid reaction. Also, in terms of the presence of diffuse infiltration of lymphocytes, and perivascular infiltration (superficial-deep), there was a significant difference between the 2 groups, and were observed more in lichenoid reaction than lichen planus. Conclusion: The characteristics of vascularity in the subepithelial area, band-like infiltration of lymphocytes, hyperkeratosis (parakeratosis-orthokeratosis), hypergranulosis, diffuse infiltration of lymphocytes, and perivascular infiltration (superficial-deep) can be used as criteria for the histopathological diagnosis of OLP and OLR.