Why do port-wine stains (PWS) on the lateral face respond better to pulsed dye laser (PDL) than those located on the central face?

Abstract

After pulsed dye laser (PDL) treatment, facial lateral port-wine stains (PWS) clear quicker and more completely than central PWS do. We sought to investigate whether the difference in the efficacy of the treatment between central and lateral facial PWS was related to different histologic manifestations. Thirteen patients with PWS had biopsies and underwent PDL treatments in both central and lateral areas of the face. The hypothesis was tested by correlating the PWS response to PDL with the depth and diameter of the PWS vessels. The clinical efficacy was assessed by chromameter 2 months after the final PDL treatment, whereas diameter and depth of PWS vessels were measured in biopsy specimens. All patients were treated on central and lateral facial sites. The chromameter evaluation showed that the average blanching rate was 34.01% and 8.68% for lateral and central facial sites, respectively (P < .05), which suggests a better response to PDL treatment in the lateral than in the central area. Histologic manifestations showed that vessels in the lateral regions were primarily located in the papillary dermis, whereas in the central regions they were extensively distributed from the dermis into the subcutaneous tissue. The small number of cases included in this study and the lack of follow-up longer than 2 months constitute limitations. Lateral facial PWS respond better to PDL than PWS located in the central face. Differences in vessel location and diameter may be responsible for the variations in PWS response to PDL.