Congenital melanocytic nevi

Purpose of review To update pediatric providers on new developments in our understanding of the clinical presentation, genetics, and systemic risks associated with congenital melanocytic nevi (CMN). Recent findings CMN are primarily caused by sporadic postzygotic somatic mutations, most frequently in NRAS, and studies of the genetic underpinnings of CMN have demonstrated a diverse array of genetic drivers. The primary complications of large and giant CMN include neurocutaneous melanocytosis and malignant melanoma. Abnormalities in CNS MRI may predict a worse clinical course for patients and increased risk of melanoma. Targeted therapies of the MEK pathway have begun to be studied for the treatment of CMN and prevention of associated complications. Summary Patients with large and giant CMN should be managed by an interdisciplinary care team for the monitoring of dermatologic, neurologic, and psychosocial concerns. Ongoing research is underway to better characterize the genetic drivers of CMN and to better guide development of targeted therapeutics.