Reflectance confocal microscopy terminology glossary for nonmelanocytic skin lesions: A systematic review

Background: There is lack of uniformity in reflectance confocal microscopy (RCM) terminology for nonmelanocytic lesions (NMLs). Objective: To review published RCM terms for NMLs and identify likely synonymous terms. Methods: We conducted a systematic review of original research articles published up to August 19, 2017, adhering to Preferred Reporting Items for Systemic Reviews and Meta-Analyses guidelines. Two investigators gathered all published RCM terms used to describe basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and seborrheic keratosis/solar lentigo/lichen planuselike keratosis (SK/SL/LPLK). Synonymous terms were grouped on the basis of similarity in definition and histopathologic correlates. Results: The inclusion criteria was met by 31 studies. Average frequency of use per term was 1.6 (range 1-8). By grouping synonymous terms, the number of terms could be reduced from 58 to 18 for BCC, 58 to 36 for SCC, 23 to 12 for SK/SL/LPLK, and from 139 to 66 terms (52.5% reduction) in total. The frequency of term usage stratified by anatomic layer (suprabasal epidermis vs epidermal basal layer, dermoepidermal junction, and superficial dermis) was 27 (25.7%) versus 78 (74.2%) for BCC; 60 (64.5%) versus 33 (34.5%) for SCC, and 15 (45.4%) versus 18 (54.5%) for SK/SL/LPLK, respectively. Limitations: Articles that were not peer reviewed were excluded. Conclusion: Systematic review of published RCM terms provides the basis for future NMLs terminology consensus.