Clinical features of subungual melanoma according to the extent of Hutchinson’s nail sign: a retrospective single‐centre study

Abstract

Hutchinson's nail sign (HS) is among the diagnostic criteria for subungual melanoma (SUM). However, there is minimal evidence supporting the overall clinical significance of HS in SUM. To identify clinicopathological features of SUM according to the extent of HS. Retrospective cohort study was performed with consecutive SUM patients at a single centre from January 2006 to December 2017. The extent of HS was defined by the number of affected nail folds (range 0-4). Comparison groups were organized as follows: patients with HS (affecting ≥1 nail folds) vs. without HS; patients with HS affecting ≥2 nail folds vs. HS affecting <2 nail folds; patients with HS affecting ≥3 nail folds vs. HS affecting <3 nail folds. Clinicopathological characteristics of SUM were compared between the groups. Sixty-one SUM patients were included. Forty-six (75.4%) exhibited HS; 22 (47.8%) on a toe and 24 (52.2%) on a finger. In multivariate analysis, nail destruction [hazard ratio (HR), 10.00; 95% confidence interval (CI), 2.61-38.30; P=0.001] was significantly associated with the presence of HS and amputation was significantly associated with HS affecting ≥2 nail folds (HR, 4.75; 95% CI, 1.36-16.61; P=0.015). High T stage (HR, 1.85; 95% CI, 1.20-2.85; P=0.005, Fig. 2) was significantly associated with HS appearing in ≥3 nail folds. Besides its value of detecting SUM, HS provides useful clinical information. The number of nail folds exhibiting HS could be a useful clinical clue for planning therapeutic strategies for SUM.