A hemangioma is a cluster or bundle of small veins that have become bunched together and dilated. Most often, people refer to the hemangiomas that are present on newborns and young children, especially on the neck and face. They can occur elsewhere in the body, such as in the liver or even the spine.
Any hemangioma is considered a tumor. They are benign, and the name tumor reflects the abnormal growth of certain types of cells. In most cases, what occurs is that endothelial cells (cells that line blood vessels) grow abnormally. This type of tumor is also called self-involuting, because the abnormal growth stops at some point, and the tumor begins to recede. It can still leave a residual red mark, sometimes as large as 2-3 inches (5.08-7.62 cm), after the tumor involutes.
In infants, a hemangioma present on the skin may start out as a flat mark, which is bluish or pink in appearance. This can then lead to growth of what looks like a raised or fatty red tumor. Hemangiomas on an infant’s skin can grow very rapidly, but they usually don’t get larger than 2-3 inches in diameter. They are not painful, but sometimes they are prone to bleeding or breaking open. Sometimes a hemangioma will grow in the deeper layers of the skin and it tends to appear as a bluish mark on part of the skin. Others grow both below and above the skin’s surface.
Learn more about hemangiomas.