A birthmark is a congenital, benign irregularity on the skin which is present at birth or appears shortly after birth—usually in the first month. They can occur anywhere on the skin. Birthmarks are caused by overgrowth of blood vessels, melanocytes, smooth muscle, fat, fibroblasts, or keratinocytes. Dermatologists divide birthmarks into two types: pigmented birthmarks and vascular birthmarks. Pigmented birthmarks caused by excess skin pigment cells include: moles, café au lait spots, and Mongolian spots. Vascular birthmarks, also called red birthmarks, are caused by increased blood vessels and include macular stains (salmon patches), hemangiomas, and port-wine stains. A little over 1 in 10 babies have a vascular birthmark present by age 1. Several birthmark types are part of the group of skin lesions known as nevi or naevi, which is Latin for "birthmarks". Birthmarks occur as a result of a localized imbalance in factors controlling the development and migration of skin cells. In addition, it is known that vascular birthmarks are not hereditary. Pigmented types
Mole
Congenital melanocytic nevus is a type of  melanocytic nevus, the medical term for what is colloquially called a "mole", found in infants at birth. Occurring in about 1% of infants in the United States, it is located in the area of the head and neck 15% of the time, but may occur anywhere on the body. It may appear as light brown in fair-skinned people, to almost black in people with darker skin.
Scrofuloderma is a skin condition caused by tuberculous involvement of the skin by direct extension, usually from underlying tuberculous lymphadenitis. : 335

See also
Scrofula
Skin lesion
List of cutaneous conditions
Tuberculosis

References
External links
 Media related to Scrofuloderma at Wikimedia Commons