Infantile hemangiomas, hemangiomas of infancy, are noncancerous vascular tumors. They are made up of cells that line the blood vessels (endothelial cells).
They are the most common tumor of childhood. About one in every 20 infants has a hemangioma. They are seen in all racial groups but seem to be more common in Caucasians. Hemangiomas happen more often in girls, premature infants, and multiple births like twins and triplets.
Hemangiomas of infancy may be visible at birth or may not be recognized until the first few weeks or months of life. Most hemangiomas are noted by 2 to 3 weeks of age. They can occur in any area of the body but the head and neck are the most common. Some lesions are small and barely visible. Others are large and very easy to see. Most individuals only have one hemangioma, but some patients may have multiple.
The cause of hemangiomas is not fully known. They are not related to drugs or medications that may have been taken during pregnancy. They are not related to any environmental exposures that may have occurred during that time. In some families, multiple family members over several generations have had hemangiomas. This happens because hemangiomas are common and not because of a genetic reason.
Hemangiomas of infancy almost always have a period of growth (called the proliferative phase). This is followed by a period of shrinkage (called the involutive phase). Most hemangiomas begin their growth phase shortly after birth. This phase lasts for four to nine months (average six months). Each lesion grows at a different rate. The involutive phase is much slower and can take up to 10 years (without any treatment). Most hemangiomas go away completely. Some hemangiomas do not shrink completely and may leave left over fatty tissue, skin discoloration or telangiectasias (tiny dilated blood vessels of the skin).
Infantile hemangiomas are different than congenital hemangiomas. Congenital hemangiomas are fully grown at birth and do not increase in size like infantile hemangiomas.