Congenital Melanocytic Nevus
A congenital melanocytic nevus is a pigmented birthmark caused by a proliferation of melanocytes (pigment producing cells) that are present at birth or develop shortly after birth.
Congenital melanocytic nevi are usually classified by size:
- Small congenital melanocytic nevi are < 1.5 cm in diameter
- Medium congenital melanocytic nevi are 1.5–20 cm
- Large or giant congenital nevi are >20cm in diameter
The risk of melanoma is related to the size of the congenital melanocytic nevus. Small and medium sized congenital melanocytic nevi have a small risk of developing into melanoma, only marginally higher than a regular acquired mole. Melanoma is more likely to develop in giant congenital nevi (lifetime estimates of developing into melanoma is approximately 5-10%), particularly in lesions that lie across the spine or where there are multiple satellite lesions. It is normal for the birthmark to grown gradually in proportion to your child’s normal growth. However, any dramatic increase in size, shape or colour should be assessed by a Dermatologist. Regardless of the size, it is recommended that you measure and monitor it closely for atypical changes. We recommend that you refer to the ABCDE chart used for melanoma diagnosis.
Over time, these birthmarks may start to grow dark terminal hairs. These hairs can be left in place or trimmed to improve the cosmetic appearance. Contrary to popular belief, cutting or shaving the hair will not cause it to grow darker or thicker.
As these birthmarks can be cosmetically disfiguring, many parents are anxious to consider treatments for removal. Unfortunately, there is not an easy way to remove these types of birthmarks. Removing a congenital pigmented nevus requires cutting out the nevus with a surgical blade, and stitching the removal site closed. Regardless of the technique, this cannot be done without leaving a surgical scar. For small and medium sized congenital nevi, surgical excision may be considered. However, in large and giant sized nevi surgical is complex, often requiring tissue expanders and the expertise of a plastic surgeon.
Although there has been tremendous advancement in laser technology, there are still no effective methods to remove or even lighten these birthmarks with laser. Even if the laser destroys the majority of the pigmented cells, the pigmentation almost always recurs as it lies in the very deep layers of the skin. As a result, observation is often the best option for most pigmented birthmarks. Although, physician evaluation is required in the event of any suspicious changes.
Cafe-au-lait is French for “coffee with milk,” which describes the color of these spots. They are light brown when found on light skin and the color of black coffee when located on dark skin. They are often oval-shaped and can range dramatically in size. They are harmless and very difficult to treat. Some areas may fade spontaneously over time, but treatment is rarely recommended.
These types of spots have a grey-blue color and are most often located on the backs or bottoms of dark skinned babies. They can look like bruises, but like most birthmarks, are not painful. These are also difficult to treat, and are most often left alone.