Nakamura Y, Matsushita S, Tanaka R, et al. - In Japanese patients with basal cell carcinomas (BCC; most common type of skin neoplasms) who had surgical excision at three institutions between January 1, 2011, and February 7, 2018, researchers conducted this retrospective study to examine the accuracy of preoperative determination of clinical tumor borders and appropriate surgical margins. The maximum calculated variations in distance between the preoperatively determined surgical margins and the actual histologic tumor side margins were considered as ‘accuracy gaps’ of clinical tumor borders. Overall, 1,000 surgically excised BCCs from 980 Japanese individuals were involved. Nodular BCC was the most frequent histologic subtype. Data reported that the median accuracy gap was 0.3 mm. The estimated side margin positivity rates with 2- and 3-mm surgical margins, respectively, were 3.8% and 1.4%. In this Japanese cohort, the determined clinical tumor border accuracy gaps were negligible. Dermatologic specialists can use narrower surgical margins with acceptable margin positivity rates. Clinical tumor borders clarity could be a suitable guide for choosing different surgical margins in the Japanese cohort.