A discoloration of the skin that is present at birth or forms shortly after. They are primarily cosmetic concerns though rarely can become cancerous. There are several kinds of birthmarks that last into adulthood. The most common of them is a congenital melanocytic nevus, or mole. These are frequent and usually small, and can occur anywhere on the body. Hemangiomas are abnormal structures of the blood vessels. These also can occur anywhere on the body but are most common on the neck and face. The port wine stain birthmark, which is a dark reddish purple blotch and can be quite large, also most often appears on the face. A dermatologist can use LASER THERAPY to fade port wine stain birthmarks. Although this treatment does not eliminate them, it does hide them. After the initial laser treatment, it takes maintenance treatments every few months to keep the birthmark faded. There appears to be a correlation between port wine stain birthmarks and GLAUCOMA, a condition in which the pressure inside the eye becomes elevated. A man who has a port wine birthmark should be certain to have regular (every six to 12 months) glaucoma checks. Most birthmarks on infants born today are treated in early childhood.