Evaluating the Frequency of Histopathological Features of Oral and Cutaneous Lichen Planus Lesions: A Retrospective- Comparative Study

Background and Aim: Lichen planus (LP) is an immunological disease of skin and mucous membranes. Cutaneous and oral LP (CLP and OLP) have almost similar histopathological changes determined microscopically with symptoms such as basal cell layer degeneration, hyperkeratosis, band-like infiltration of lymphocytes, and saw tooth ridges. The present study aimed to determine the frequency and compare the histopathological features of OLP and CLP samples. Materials and Methods: This was a descriptive-analytical, and cross-sectional research performed on 91 paraffin-embedded tissue blocks (41 OLP lesions and 50 CLP lesions). The frequency of histopathological features was determined by an optical microscope, and data analysis was performed in SPSS version 21 using descriptive statistics (frequency and percentage) and Chisquare. Results: In this study, the frequency of LPs was higher in female subjects, compared to male participants. The frequency of histopathological features of hyperkeratosis, acanthosis, spongiosis, and epithelial hypertrophy was significantly higher in CLP samples, compared to OLP lesions (P<0.005). Meanwhile, the frequency of saw tooth ridges was higher in OLP lesions, compared to CLP samples (P<0.008). Moreover, there was a severe frequency of basal cell layer degeneration and the presence of civatte bodies (CBs) in most CLP lesions while they were moderate in most OLP samples. Conclusion: According to the results of the study, histopathological features of OLP and CLP lesions were not completely similar and had different frequencies in the two groups. It is recommended that more comprehensive studies be performed on these differences and their causes.