Definition of Port wine stain

Port wine stain: A mark on the skin that resembles port wine (porto) in its rich ruby red color. Due to an abnormal aggregation of capillaries, a port wine stain is a type of vascular malformation (vascular birthmark). A port wine stain on the face is a sign of the Sturge-Weber syndrome.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=5005
Last Editorial Review: 9/20/2012