Association between dermoscopic features and tumor thickness, diameter, age, and sex in acral melanoma: A cross-sectional study.

Background: Although dermoscopy is useful for the early detection of acral melanoma (AM), the relationships of dermoscopic findings with factors such as tumor thickness (TT), lesion diameter, patient's age, and sex remain unclear. Objective: To investigate the relationships of dermoscopic findings with TT, lesion diameter, patient sex, and age. Methods: Ninety-four patients with AM were included in the retrospective cross-sectional study. Multivariate analysis was performed to determine the relationships of dermoscopic findings with TT, diameter, age, and sex. Results: Compared to in situ lesions, lesions with TT > 4 mm had significantly more irregular dots, blue-gray clods, blood crusts, shiny white lines, and blood vessels, and significantly less parallel ridge patterns. Regression structures and the micro-Hutchinson sign were commonly observed in situ. With an increase in diameter, the number of peripheral black dots decreased predominantly. With an increase in age, regression structures and milky red globules became more frequent. Blood vessels were more commonly found in women. Limitations: This was a retrospective study with a small sample size that included patients with nail melanoma. Conclusions: TT, diameter, age, and sex may affect dermoscopic findings of AM. Clinicians should consider these factors when examining patients with acral pigmentation.