Dramatic spontaneous regression of a medium-sized congenital melanocytic naevus.

We report a case of a 6-month-old girl who was referred for evaluation of a congenital melanocytic naevus (CMN) on her right thigh. The lesion was consistent with a medium-sized CMN and was managed conservatively. A halo of depigmentation, which coincided with occlusion of the lesion during a holiday in a sunny climate, was noted soon after her fourth birthday and the CNM regressed completely over a 4-month period. A residual patch of leucoderma still remained at the original CMN site > 2 years after its total involution. The process has been documented with photographs and a skin biopsy during the resolving phase.