A 3-month-old girl was brought to the clinic with a large vascular growth over her left cheek and zygoma. When the child was delivered uneventfully at 37 weeks, her mother noticed only a bruiselike discoloration in the area. Over the next several weeks, however, the lesion rapidly enlarged into a thick plaque. There was no associated bleeding or discomfort. The baby appeared healthy; no problems had been identified on her routine well-child visits to date. She was playful and growing appropriately.