Port-wine stains. Morphologic variations and developmental lesions.

Studies have shown that port-wine stains (PWSs) probably represent a progressive ectasia of the superficial cutaneous vascular plexus. During examination of approximately 500 patients with PWSs, seven lesions were identified that could be categorized into two groups. In one group (two patients), the typical superficial PWS was accompanied by a proliferation and ectasia of thin-walled vessels in the deeper dermis, subcutaneous adipose tissue, and skeletal muscle (cavernous hemangioma). In the other group (five patients), single or multiple polypoid tumors arose that consisted of a proliferation of vessels with walls of varying thickness, and intervascular stroma (arteriovenous malformation). These tumors appear to arise in both young patients with flat lesions as well as the older patients with pronounced surface irregularities. Two patients were specifically chosen because they represented the typical PWS cobblestone pattern. This vascular abnormality represents a localized exaggeration of the ectasia process. We conclude that a small number of PWSs are associated with an underlying cavernous hemangioma. Furthermore, besides the surface irregularities that characterize the older PWS, de novo vascular tumors arise that can be categorized as arteriovenous malformations.