Congenital Melanocytic Nevi: An Update

Dr. Carrie Coughlin presented information about the clinical evaluation, treatment, and management of congenital melanocytic nevi (CMN).

First, Dr. Coughlin discussed CMN clinical evaluation and risk assessment. Initial evaluation includes a physical exam with palpation because melanoma can present underneath the skin. If the nevus is large or giant, Dr. Coughlin also examines the lymph nodes. Clinical judgement is needed to determine whether lymph node findings are CMN or melanoma. An ultrasound can visualize the architecture and follow lesions over time.

The risk of melanoma in patients with CMN increases with the size, presence of neurocutaneous melanosis, and number of satellites. Dr. Coughlin noted that the term “satellite” is shifting but is still used for sizing categories. Two-thirds of melanomas in patients with CMN are in the central nervous system.

Melanoma risk is <2% in small or medium CMNs. CMNs do not necessarily need to be removed because current research shows removal does not affect the risk of melanoma development.

For children at risk of neural melanosis, early screening can be helpful, as myelination increases with age, making neural melanosis more difficult to detect. Screening can be completed without sedation in young children (the age cut-off varies across hospitals). Children can develop neural melanosis later in childhood, but it may be difficult to see on MRI. There are no routine screening guidelines for neurocutaneous melanosis. Complications can include seizures, learning difficulties, and behavioral and neuropsychiatric issues.

Second, Dr. Coughlin discussed the treatment and management of CMN. She emphasized the importance of multidisciplinary care, including general and plastic surgeons, radiologists, pathologists, neurologists, and neuropsychologists.

Dr. Coughlin noted the psychological impact of CMN. Typically, families are surprised by their child’s CMN, as it is not typically diagnosed before birth. Dr. Coughlin recommended asking the family about their experience and taking more time with families when the patient has a large or giant nevus, more visible nevus, or multiple nevi.

Third, Dr. Coughlin discussed the genetics of CMN. NRAS variants are the most common genetic cause of CMN; others include BRAF variants, as well as BRAF, RAF and ALK fusion proteins.

Finally, Dr. Coughlin discussed ways that dermatologists can impact patients and their families in meaningful ways. In addition to procedures, repurposed targeted therapies such as the mitogen-activated protein kinase (MEK) inhibitor trametinib may relieve symptoms.

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