Birthmarks

Benign irregularities on the skin that are present at birth or appear shortly after birth, usually in the first month. Dermatologists divide birthmarks into two types: pigmented birthmarks caused by excess skin pigment cells that include moles, café-au-lait spots and Mongolian spots; and vascular birthmarks (also called red birthmarks) that are caused by increased blood vessels and include macular stains (salmon patches), hemangiomas and Port-wine stains. Several birthmark types are part of the group of skin lesions known as nevi or naevi, which means "birthmarks" in Latin; and although nevi are benign by definition, half of all melanomas arise from pre-existing nevi.