The patient, a 3.3-year-old girl, first presented with a quarter-sized bruiselike lesion on the right side of her neck. Over the subsequent eight months, the lesion gradually enlarged to a palm-sized oval macular area on the right side of her neck, with extension toward the anterior midline. The parents noted no swelling or discoloration present at birth. The child took no medications, including aspirin, and was otherwise in good health.Physical examination revealed a well-developed, alert, healthy-appearing young girl. On the anterior right side of her neck was a 5-cm macule with a central, ill-defined, indigo-to-purple region surrounded by a more deeply blue area admixed with streaks of yellow and green (Fig 1). Careful palpation revealed minimal soft-tissue swelling in comparison with the left side of the neck and a small freely moveable lymph node (8 mm) directly beneath the lesion. Induration was not a feature. The patient's neck measured 28 cm in circumference. Hematologic and otolaryngologic evaluations were unremarkable, except for poorly draining middle ears, necessitating eustachian tubes. A roentgenogram of the neck and cervical spine was unremarkable. The clinical differ¬ ential diagnosis of the neck lesion at that time included a traumatized nevus flammeus, morphea, or battered child.A 4-mm punch biopsy specimen was obtained, and the findings were as follows: At low power, the specimen appeared unremarkable (Fig 2); however, the abnormality was more apparent at higher power (Fig 3). Within the dermis and subcutaneous tissue, there were irregularly shaped, angulated, sometimes interconnecting, endothelial-lined vascular channels extending from the upper reticular dermis to the deep reticular dermis.