Halo congenital nevocellular nevi associated with extralesional vitiligo: a case series with review of the literature.

Halo formation in association with congenital nevi is uncommon and is postulated to have an immunologic etiology. In this report, we present nine cases of patients with congenital nevi and vitiligo who uniquely developed both halo formation around the nevi in addition to vitiligo formation in distinctly separate locations. While the precise etiology of halo formation and vitiligo remains uncertain, several theories suggest that both phenomena result from an immunologic response to pigment cells, whether in the "normal" skin of vitiligo or in the excessively pigmented congenital nevus.