Dermoscopy Features of Port-Wine Birthmarks: A Retrospective Study of 1,136 Cases.

Abstract

Background: Port-wine birthmarks (PWBs) are congenital capillary malformations affecting approximately 0.3%-0.5% of newborns. - However, large-scale studies characterizing their dermoscopic features remain limited.

Aims: This retrospective observational study aimed to analyze the dermoscopic features of 1,136 cases of PWB.

Methods: Clinical data and dermoscopic images were retrospectively obtained from 1,136 patients with PWB examined between October 2020 and June 2025. Dermoscopic findings were classified into vascular and nonvascular morphological patterns. Multivariable multinomial logistic regression models were used to assess the associations of dermoscopic morphology with age group, sex, anatomic location, clinical subtype, and previous treatment history.

Results: In total, 1,136 patients with PWB were included. Linear vessels were the most common vascular pattern (32.31%). Compared with linear vessels, dotted or globular vessels were more commonly observed on the neck than on the face (aOR 1.95, 95% CI 1.32-2.46, P < 0.01), whereas reticular and mixed vascular patterns were more commonly observed on the trunk and limbs. Hypertrophic PWBs were more likely than pink PWBs to exhibit reticular vessels (aOR 1.86, 95% CI 1.17-2.78, P = 0.01) and mixed vascular patterns (aOR 4.11, 95% CI 2.45-6.01, P < 0.001). Previous treatment was associated with a whitish veil (aOR 7.56, 95% CI 5.44-9.98, P < 0.001) and a pale halo surrounding a central spot (aOR 4.19, 95% CI 2.01-6.32, P < 0.001). Hypertrophic PWBs were also more likely to exhibit both nonvascular features.

Conclusion: Our findings demonstrate that dermoscopic vascular and nonvascular patterns are associated with clinical subtype, anatomical location, and previous treatment history in PWB. Prospective studies are warranted to determine whether these dermoscopic features have predictive value for treatment response.