2021 Volume 30 Issue 4 Pages 355-362
Clinically suspected oral lichen planus (OLP) includes histopathologically proven OLP, oral lichenoid lesion (OLL) or lichenoid stomatitis, and oral lichenoid dysplasia (OLD). Malignant transforming potential of OLD is a diagnostic issue. This study aimed to exclude OLD from OLP and OLL and examine the role of OLD in malignant transformation. Immunostaining for CK13, CK17, p53, Ki-67, Coxsackie‒adenovirus receptor (CAR) and E-Cadherin was conducted in 200 cases. CK13-positive rate was lower in OLD (33.3%) than in OLP and OLL. CK17-positive rate was slightly lower in OLP (89.2%) compared to OLL and OLD. Ki-67- positive rate from basal to spinous layer was higher in OLD (30.6%) than in OLP and OLL, and p53 showed similar trend (OLD: 19.4%). Rate of attenuated CAR staining intensity from basal layer to lower one-third of spinous layer was higher in OLD (77.8%) compared to OLP and OLL, similar to rate of attenuated E-Cadherin staining (OLD: 45.8%). In conclusion, a diagnosis of OLP or OLL is indicated when the lesion is CK13 positive and CK17 positive, with no attenuation of staining intensity for CAR and E-Cadherin from the basal layer to the lower onethird of the spinous layer. On the other hand, a diagnosis of OLD is indicated when the lesion is CK13 negative and CK 17 positive, with attenuation of staining intensity for CAR and E-Cadherin from the basal layer to the lower one-third of the spinous layer. In OLD, attenuated CAR expression may participate in malignant transformation by weakening cell junction in the epithelium and inducing epithelial mesenchymal transition.