Time-sequence histologic imaging of laser-treated cherry angiomas with in vivo confocal microscopy

Objective: To chronicle the pathophysiologic changes chat occur subsequent to laser treatment of vascular lesions, we used a confocal scanning laser m icroscope that yields high-resolution microscopic images of skin in vivo. Methods: Cherry angiomas were treated with the 585-nm flashlamp-pumped puls ed-dye laser (PDL) and the 568-nm continuous-wave krypton laser. Repeated c onfocal reflectance imaging was performed before and immediately after trea tment, as well as after several hours, 1 day, 2 days, 1 week, 2 weeks, 3 we eks, and 4 weeks. Results: Before treatment, confocal images revealed dilated blood vessels r anging from 10 to 50 mu m in caliber, closely spaced at 5 to 50 mu m apart. After PDL treatment, amorphous cords of refractile material conformed to t he shape of the original vessels, followed by dark nonrefractile spaces whe re the vessels once were. Inflammation and necrosis ensued, with eventual r eplacement after 3 weeks by normal-appearing skin. After krypton laser trea tment, dark nonrefractile spaces appeared immediately with subsequent infla mmation, necrosis, and eventual healing by 4 weeks. Conclusion: Confocal laser microscopic imaging elucidates the dynamic patho physiologic events that occur after laser treatment of vascular lesions and has added insight into the different mechanisms of vessel damage induced b y the PDL and krypton laser.