4

The value of dermoscopy for further evaluating venular malformations (VM) has been proposed.(1) Venular malformations (or capillary vascular malformations) are congenital, low-flow, vascular abnormalities of the dermal capillaries. VM affect 0.3%–0,5% of newborns with equal prevalence in male and female patients. They may have a genetic basis, tend to be present at birth, and grow with age. VM are initially flat and smooth (macular) but nodules may develop with time. The color varies from pink, red, to deep purple. VM may be part of syndromes such as Sturge-Weber and Klippel-Trenaunay. Very rarely, VM may present late onset in adolescents and adults, usually caused by trauma. VM are characterized by ectatic vessels with flattened endothelium, most of them situated in the papillary dermis and upper part of the reticular dermis, but may be located deeper. The origin of VM is unclear, possibly being a result of vascular channel developmental defects or segmental deficiency of autonomic inervation of postcapillary venules.(2, 3)

VM are being classified according to their color and location. In addition, the recent introduction of noninvasive image techniques such as dermoscopy or videodermoscopy has allowed the analysis of the capillary composition, that is, the type of the capillary involved (4-8) (Figures 6.44-6.57), which may be related to prognosis. By means of these devices, a better understanding of the morphology of the vessels involved can be obtained in daily practice, and rapidly, without the risk of injury to the patient and without additional cost, revealing significant vascular structures hidden in the standard visual inspection. By means of dermoscopy, the vessels are visualized

Figure 6.44 Clinical view of a flat, partially treated, long-standing venular malformation (VM) of the forehead.