Congenital Nevi

Congenital nevi are present at birth and are caused by an abundance of non-cancerous melanocytes in one or both of the two outer layers of the skin. Within the first two years of life nevi that are identical in tissue structure to congenital nevi may develop even though they are not present at birth. The name for this later development is called congenital nevus tardive.

Congenital nevi are one of the risk factors that can lead to an increased risk for the later development of melanoma. Although malignant melanoma is still not common in children who haven’t reached puberty. Although it is common for patients to have concern about regular and changing nevi. Although the occurrences of melanoma rises considerably once a child reaches puberty by a rate of .7 cases per million at ages 0-9 years to an alarming 13.2 cases per million for ages 15-19 years.

Several sources have noticed the alleged melanoma epidemic among adults, but only recently data has started to document a startling rise in melanoma cases among young people. The identification of childhood risk factors for melanoma along with the increase allows doctors in the 21st century to help actively identify children who are at risk of developing melanoma and help prevent it by educating individuals about the risk of exposure to ultraviolet light exposure.


It is still not clear what causes congenital melanocytic nevi. At this time the exact type of cell of their origin is not known although melanocytes of the skin begin in the neuroectoderm. A reasonable theory is that the transformation is caused by external insult affects the development of the budding neural plate as well as migration of originator cells to the skin.

There are three groups of congenital nevi based on their size: the small nevi grow no bigger than 1.5 cm, the medium grow between 1.5 and 19.9 cm in diameter and the large or giant nevi grow over 20 cm in diameter. The giant nevi are often surrounded by smaller satellite nevi.

A rare congenital condition known as neurocutaneous melanosis is although thought to be a part of congenital nevi. The presence of congenital melanocytic nevi and melanotic tissue masses that encompass the central nervous system is including in the characteristics of neurocutaneous melanosis.

First described in 1861, neurocutaneous melanosis has current criteria that is used for diagnosis of the condition. Including large or multiple congenital nevi along with meningeal melanosis or melanoma and no evidence of meningeal melanoma other than in patients whose skin lesions are benign and no evidence of skin cancer except in patients whose meningeal lesions are benign.

Patients may be born with increased intracranial pressure from a clinical standpoint because of hydrocephalus or a mass lesion. Patients have a very meager outlook even if the symptomatic neurocutaneous melanosis is not malignant. In thirty-nine reported cases of symptomatic neurocutaneous melanosis that were studied more than half the patient died within three years after the neurological symptoms started and most of the deaths occurred in individuals under the age of ten.


Based on the size and location, congenital nevi may impact cosmesis. Patients have a greater risk of developing melanoma at the site of the nevus if they are diagnosed with giant congenital nevi. By age sixty for patients with giant congenital melanocytic nevi the risk has been shown to be as high as 5.7 percent in reports. It has been suggested that diagnosed individuals have a greater risk of developing melanoma if they have congenital melanocytic nevi or if they have a larger number of satellite lesions or are larger in diameter. Another general belief is that smaller nevi present an increased risk for development melanoma compared to normal skin but the risk hasn’t yet been quantified.

Medical Care

There are a number of factors that determine the treatment plan for management of congenital melanocytic nevi. This includes the size of the lesion, where the lesion is located, how old the patient is, how cosmesis might be affected and what is the potential for malignant transformation.

Surgical Care

The congenital melanocytic nevi may need to be surgically removed in order to improve the patient’s cosmetic appearance and to ensure the reduction in the likelihood of malignant transformation. Giant congenital melanocytic are removed if possible since it is well known that there is an increased risk of malignant transformation with these. The lesion size and location in relation to vital structures may prevent removal in certain situations. Other procedures may need to be used in these cases such as curettage of the lesions or laser treatment of the lesions.

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