Baby has a congenital nevus: what is this mole?

When the baby was born, it had a spot on its body, often on its back, that medical staff called a nevus? It is actually a large mole that needs to be watched by a dermatologist.

Definition: what is a nevi or congenital nevi?

A congenital nevus looks like a mole and is linked to a benign proliferation of melanocytes, cells that pigment the skin. Often the smallest of them grow together. Their size is very variable and their color generally fluctuates between brown and bluish. Hair sometimes grows on it.

Dr Nathalie Bodak, dermatologist, specifies: “ There are congenital nevi, and other so-called acquired nevi that can appear beyond a year. It iscongenital (which means that it comes with birth, editor’s note) but not hereditary, simply due to a fluke for sustainable. These nevi can settle anywhere on the body. »

The risk that the nevus degenerates into melanoma is very weak, even in adulthood, reassures the specialist: ” Indeed, in the – extremely rare – case of a giant nevus which would make all the back or the whole head, there is a risk of 2 to 3% of developing melanoma during infancy. For small nevi, the risk is below 1% and only concerns adults.

When do we start talking about a giant nevus on an infant?

Congenital nevi are qualified as giants when the size of the lesion is greater than or equal to 6 cm² at birth. Some can cover up to 90% of a baby’s body.

Whether it is multiple congenital nevi or a congenital giant nevi, this skin abnormality is very rare, affecting one in 50 infants.

Surgery: how to remove a congenital melanocytic nevus?

A melanocytic nevuscongenital is not removed that in certain situations, in order to avoid too heavy and unnecessary surgery for our baby. It is a question of evaluating the possible risks according to the size of the nevus projected in adulthood: ” If it is less than 1,5 cm, there is no excess risk », Says Dr Nathalie Bodak.

If there is no treatment for the nevus, it is possible to perform an operation called resection : the nevus is removed and the opening is immediately closed thanks to the elasticity of the skin. If the elasticity of the skin is not sufficient and the size of the lesion is too large, surgeons may suggest two other methods: that of theprior skin expansion, which consists of using healthy skin nearby, or even a skin graft.

Face, scalp, head, medium or large, hairy … The ablation depends on the nevus

The decision to have surgery is often motivated by aesthetic factors, since the lesion is benign in the vast majority of cases: ” If the nevus looks like a brown hairy spot on a social area, we will tend to suggest the operation. The larger the nevus, the earlier you have to see the plastic surgeon. It is easier to operate when you are small », Emphasizes the dermatologist. This is therefore decided on a case-by-case basis, between the practitioner and the parents, who assess the possible psychological suffering of the child if the nevus is large.

In the case of a nevus on the scalp, Nathalie Bodak explains that there is ” no aesthetic gain with surgery. The scar will be visible because the operation shifts the organization of the follicles. Aesthetically, it is less annoying, so we have less reason to remove it, however it will be more difficult to monitor.

No treatment, but annual monitoring

It is better to take the time to weigh the pros and cons with the surgeons, and to assess the size of the child’s nevus when it comes to adulthood. Although it is important to take into consideration the psychological suffering in case of possible mockery, the dermatologist recommends rather to be very attentive to the modifications of the nevus and consult a dermatologist once a year.