Histopathological evaluation of oral lichen planus

Background : Oral lichen planus (OLP) is a chronic inflammatory disorder affecting mucosal surfaces, which can cause an important discomfort to the patients . To highlight the most characteristic histopathological findings of OLP which are useful in making a diagnosis of OLP. In addition, by studying the association of these findings it was hoped that information about pathogenic mechanism would be obtained. Material and Methods : In this study a retrospective analyses of 194 cases of OLP being diagnosed at Oral and Maxillofacial Pathology Department, College of Dentistry , were obtained over a period of 26 years, spanning from 1985- 2010 . We analyzed the age and sex of the patients, clinical type of lichen planus, site and different histopathological finding, comparing them with each others. Results : (61 %) of the patients are female and (39 %) are males, with an average age for both sexes (49.75 years). The most frequent clinical form is reticular, presented in (78 %) of cases, and the most common location is buccal mucosa, presented in (60 %) of the patients. The mononuclear infiltration beneath and adjacent to the epithelium, parakeratosis and degeneration of the basal layer of the epithelium were consistent features. Linear regression analysis revealed a positive correlation between basal degeneration and mononuclear infiltration and an inverse correlation between the mononuclear infiltrate and the parakeratosis. Conclusion : Linear regression analysis of the parameters studied provided partial support for a cell- mediated immune mechanism.