Genetic Abnormalities in Large to Giant Congenital Nevi: Beyond NRAS mutations

Large and giant congenital melanocytic nevi (CMN) are rare melanocytic lesions mostly caused by post-zygotic NRAS alteration. Molecular characterization is usually focused on NRAS and BRAF genes in a unique biopsy of the CMN. However, large/giant CMN may exhibit phenotypic differences among distinct areas, and patients differ in features such as presence of multiple CMN or Spilus-like lesions. Herein, we have characterized a series of 21 large/giant CMN including Spilus-type nevus patients (9/21 cases, 42.8%).