Spontaneous Regression of a Congenital Melanocytic Nevus by Sclerosis

Congenital melanocytic nevi (CMNs) naturally evolve throughout life, growing proportionately with the child, darkening, and exhibiting textural or surface changes (e.g., papillomatous, verrucous, cerebriform), hypertrichosis, and, later in life, lightening of pigmentation. We report the case of a 5-year-old child with complete resolution of a medium-sized CMN involving the distal left leg and foot via sclerosis and in the absence of any halo phenomenon. Spontaneous regression of CMN via sclerosis is rare, and it is thought that an immunologic mechanism different from the mechanism that the halo phenomenon induces mediates this regression. We reviewed the literature on this phenomenon and discuss how it might lead to regression of the nevus.