The differential diagnosis of lichenoid keratosis and seborrheic keratosis with reflectance confocal microscopy: a preliminary study

Abstract

Backgrounds and Objectives: The lichenoid keratosis(LK) and seborrheic keratosis(SK) have similar lesions on cosmetically sensitive area,but require different therapies. The histology analysis could easily identify LK and SK, however, the biopsy may cause scarring and result in hyper-pigmentation, which reduced the compliance of the patients to be biopsied. In this study, we investigated the role of reflectance confocal microscopy (RCM) in the non invasive differential diagnosis of LK and SK.Patients and methods: Cases with facial brown patches or plaques suspicious of SK were enrolled in the study. After written informed consent was obtained, the lesions were photographed,imaged by RCM,and then biopsied. The RCM findings were analyzed and correlated with histology results.The evaluation of the RCM pictures and confirmation with histological results were conducted by two independent dermatologists.Results: 10 cases were enrolled in the study.The main characteristics of LK lesions observed by RCM were the disarray of the dermal and epidermal junction(DEJ), and the marked inflammatory infiltration in the superficial dermis; while those with cerebriform pattern, or elongated cords with bulbous projections without significant inflammation reaction, were the features of SK.Among the 10 cases, clinically suspicious of facial SK, 4 were determined as LK, 6 as SK by RCM imaging, and all the RCM findings were confirmed by histological results.Conclusions: The presence of DEJ disarray and inflammatory infiltration in the superficial dermis is the main pattern of LK. The RCM features of LK and SK have significant difference, highlighting the important role of RCM in the differential diagnosis of LK and SK.