Histopathological and Immunohistochemical Study of the Distinction Between Oral Lichen Planus and Oral Lichenoid Lesions

Background: Oral potentially malignant disorders, which include oral lichen planus (OLP), are clinical presentations that carry a risk of development to cancer in the oral cavity.Oral lichenoid lesions (OLLs) are also termed interface/lichenoid mucositis.Malignant transformation of them remains controversial, but distinct clinical and histological criteria for how to differentiate OLP from OLLs have not been developed.Objectives: The purpose of this study was to elucidate findings that can allow histopathological differentiation of OLP and OLLs using histomorphological and immunohistochemical analyses.Materials and Methods: Analyses were performed in 10 cases diagnosed with OLP and 9 cases diagnosed with OLLs.Cytokeratin 19 (CK19), Ki-67 and CD3 were used as primary antibodies to detect basal cells, proliferative activity and T-cell distribution, respectively, and Perlecan and COX-2 to evaluate epithelial intracellular arrangements and interstitial distributions of proteoglycans and enzymes.Results: For CK19, positive cells were significantly found in OLLs at both the prominent area and site adjacent to the lesion comparison with those of OLP's.The number of COX-2 positive cells was significantly higher in spinous and basal layers in OLLs of the prominent area.Additionally, OLLs showed mild to moderate expression for perlecan in the basal to spinous layers and in subepithelial tissue.Conclusion: Almost no basal cells were noted in the prominent area in OLP.COX-2 and perlecan were found in the basal to spinous layers in OLLs.Although there are restric-