Birthmarks. Birthmarks are skin irregularities that are present from birth or shortly after. They are common occurrences that are usually benign and do not require .Learn about Birthmarks symptoms and causes from experts at Boston Children's, ranked best Children's Hospital.Identify and describe newborn congenital skin lesions aka “birthmarks”. 2. Identify common vascular birthmarks; distinguish worrisome from benign. 3. Identify .Vascular birthmarks are categorized into two groups: (1) Vascular Tumors, of which hemangiomas are the most common, and (2) Vascular Malformations.Birthmarks that babies are born with, or develop soon after birth, are mostly harmless and many even go away on their en español Manchas de nacimiento.