The use of a flashlamp-pumped, 585-nm dye laser (Candela Laser Corp, Wayland, Mass) has proved a major advance in the treatment of port-wine stains. However, not all stains respond equally and some, which may be clinically indistinguishable, do not respond at all.1-3
To investigate this phenomenon we used transcutaneous videomicroscopy (Moritex Scopeman 503, Moritex Europe, Cambridge, England) at 200-fold magnification in 2 groups of patients with port-wine stains: 15 patients before treatment and 13 patients who had shown a poor response to previous treatment. Response to treatment was graded excellent (>75% clearing), good (50%-75% clearing), or poor (<50% clearing).
Two major patterns of vascular abnormality were identified: type 1, consisting of superficial, tortuous, dilated end capillary loops (blobs) (Figure 1), and type 2, composed of dilated, ectatic vessels in the superficial horizontal vascular plexus (rings) (Figure 2 and Figure 3). In some patients both types were present, although type