Characterization of vascular stains associated with high flow

Background: High-flow vascular stains (HFVS) are lesions that have the appearance of capillary malformations/port wine stains but are associated with increased arterial flow. Objective: To identify features of HFVS that differentiate them from typical “slow-flow” port wine stains. Methods: Retrospective multicenter cohort study of HFVS evaluated across 7 centers was conducted. HFVS were characterized by clinical features (warmth, thrill, rapid capillary refill), radiologic findings (fast flow), or mutations associated with capillary malformation-arteriovenous malformation syndrome. Investigators reviewed photographs. Results: The study reviewed 70 patients with HFVS (47 multifocal and 23 solitary). Most were flat (77%), warm to the touch (60%), and red or pink-red in color (35%), with heterogeneous color saturation (73%) and well-defined borders (71%). Regional soft tissue swelling/overgrowth was common (47%). Head and neck location was most common (38%). Among 34 HFVS with photographic review over time, all demonstrated changes in appearance. Limitations: Retrospective design, recall bias, lack of standardized time points or visual analog scale, and image variability. Conclusion: Heterogeneity of stain color saturation, warmth to touch, peripheral pallor, and overgrowth/soft tissue swelling help distinguish HFVS from port wine stains. Darkening of color and increased border demarcation may develop over time. These findings raise suspicion for HFVS and provide an indication to assess for extracutaneous involvement.