Abstract: Objective: To investigate the diagnostic sensitivity and specificity of image features of lichen planus by Reflective Confocal Microscope (RCM). Methods: RCM was performed on patients suspicious of lichen planus in our hospital, and then histopathological examination were done on the same lesion. The characteristics of RCM images were correlated with histopathological results. The common features of images were extracted, and then the sensitivity and specificity of diagnosis of these image features were analyzed. Results: A total of 78 patients were enrolled in the study group. The image features of RCM in lichen planus were as follows: (1) irregular thickening of stratum corneum and granular layer ; (2) irregular thickening of spinous layer with downward extension of epidermal rete ridges; (3) liquefaction degeneration of basal cells; (4) banded infiltration of lymphocytes and histiocytes in superficial dermis layer. The sensitivity and specificity of basal cell liquefaction degeneration were 97.87% and 58.06%, respectively. The specificity of the group with（2）+（4） was 93.55%. Conclusion: The RCM images of LP correlated very well with histology analysis and the high sensitivity and specificity of RCM features of LP could be used for routine screening of LP.

Key words: RCM, lichen planus, specificity and sensitivity