Vascular birthmarks are common, idiopathic (of unknown cause) clusters of blood vessel growths found in infants and children. They are present at birth but may not have a noticeable appearance for weeks and sometimes years.
These birthmarks are classified in two groups: tumors and malformations. Vascular tumors are neoplasms, involving cellular proliferation of vessels. Vascular malformations, on the other hand, do not involve active proliferation of the blood vessels and are stable throughout one’s lifetime; they are further classified according to the type of vessels found in the birthmark.
Examples of vascular tumors include:
Examples of vascular malformations include:
Oftentimes, these vascular birthmarks are stand-alone lesions, without association with other findings. Occasionally, however, vascular birthmarks may be found in a larger constellation of physical findings, comprising a vascular malformation syndrome such as Sturge-Weber syndrome or Klippel-Trenaunay syndrome. This is one reason why it is important for vascular birthmarks to be evaluated by a pediatric dermatologist.