Prepubertal Melanoma Arising within a Medium-Sized Congenital Melanocytic Nevus.

We report the case of an 8-year-old child who developed a 9.4-mm-deep melanoma within a medium-sized congenital melanocytic nevus on the scalp. Genetic analysis revealed an activating NRAS Q61R mutation within the melanoma, which is more commonly associated with large or giant congenital melanocytic nevi. This case demonstrates that even a "low-risk" congenital melanocytic nevus at a "low-risk" age must be monitored regularly for the development of malignancy.