Ko D, et al. - In this Retrospective cohort study of 84 patients who underwent nail matrix biopsy for longitudinal melanonychia (LM) from January 2011 to November 2017 to evaluate the clinical and dermoscopic characteristics of LM, ABCDEF criteria, and risk of malignancy. They observed more incidence of subungual melanoma (SUM) among younger cases. They had their melanonychia longer, presented with a wider band and greater width percentage as compared to subjects with benign LM. They noticed less consistent clinical and dermoscopic signs. Hence, they found no variation in the number of ABCDEF criteria between the groups.