Blood vessel proliferations (hemangiomas) are the most common benign tumors in infants and children. About 10% of infants have them, and they are usually present at birth or within the first 2 or 3 months of life. Hemangiomas undergo a rapid phase of growth followed by a slow period of clearing up or disappearing (called involution). Most hemangiomas are solitary tumors that appear most commonly on the head and neck, but they may also appear on the trunk and extremities.
Causes of Hemangiomas
Hormones most likely influence the rapid development and proliferation of blood vessels that result in a hemangioma. The exact mechanism of enlargement and ultimate involution is not entirely understood. Female infants are three times more likely to have a hemangioma. Hemangiomas are seen in almost 25% of premature infants who have a birth weight of less than 2 pounds.