Spontaneous Regression of a Nail Matrix Melanocytic Nevus in a Child.

A 14-year-old Hispanic boy presented with a 0.25-mm wide, sharply demarcated, dark brown band of longitudinal melanonychia of the left thumbnail. A clinical diagnosis of nail matrix nevus was made and the boy was scheduled for follow-up. The band showed proximal fading after 6 months and had completely faded after 11 months, with the proximal nail fold showing small dark brown dots on dermoscopy. We documented the spontaneous regression of melanonychia over 11 months.