Congenital Nevi

Also known as: congenital moles, congenital melanocytic nevus

What are congenital nevi?

Congenital nevus/i (plural) is simply the term for a single small/ medium sized solitary flat or raised tan/dark mole (birthmark) that develops from proliferation of pigmented cells (melanocytes) on/in the skin that is present on a baby at birth or within a year or two thereafter.

There is a small risk that these may go on to becoming cancerous. A rare form of congenital mole is the large or giant melanocytic nevus which may be small at birth but grow in size as the child grows. These moles have a greater risk of becoming malignant (a cancer called a melanoma).

A syndrome called Neurocutaneous melanosis is the presence of small or giant congenital melanocytic nevi on the skin plus melanocytic tumors in the coverings of the brain and spinal cord.

What causes congenital nevi?

Congenital nevi are thought to be caused by a non inherited genetic mutation that occurs randomly in the early stages of fetal development.

What are the symptoms of congenital nevi?

Congenital nevi can be big or small. They are typically skin-colored to brown, flat or raised, with or without hairs and can occur anywhere on the body.

What are congenital nevi care options?

In many cases, no treatment is needed for congenital nevi. If a doctor is concerned about the nevi, it might require additional monitoring to assess the potential cancer risk, or removal. Removal of the mole is typically a simple, fairly painless procedure.

Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: July 12, 2021 03:04 PM

Children's Dermatology

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Melanocytes are the cells in the body’s skin that produce melanin. Melanin is the pigment that gives skin its color. When cancer develops in the melanocytes, it is known as melanoma. Learn more