Congenital nevus: Small to large nevus present at or near time of birth.

For the congenital nevus, the neval cells are found deeper into the dermis.

New York Times: "Congenital Nevus On the Abdomen."

Provides a network of support and information for people with a large brown birthmark called a giant congenital nevus and/or an associated condition called neurocutaneous melanosis.

Acquired nevus: Any melanocytic nevus that is not a congenital nevus or not present at birth or near birth.

Congenital defects may include aplasia cutis congenita, congenital nevus, congenital vascular malformations and congenital tumors.

Call for an appointment with your provider if there is development of pain, inflammation, ulceration, bleeding or itching of a congenital nevus or other skin lesion, or if you have questions or concerns.

While this is likely safe and effective for small congenital nevus, laser removal for larger lesions might pose a liability for the laser surgeon if malignancy developed from a deep (dermal) component of the nevus that is not reached by the laser.