Unusual Halo Nevi – Darkening Rather than Lightening of the Central Nevus

Abstract

Although the classic halo nevus is a brown nevus with a surrounding rim of depigmentation, i.e. a stage I halo nevus, these nevi can have several clinical stages. The central nevus may lose its pigmentation and appear pink with a surrounding halo (stage II), the central papule may disappear leading to a circular area of depigmentation (stage III) or the depigmented area may repigment (stage IV), leaving no trace of its prior existence. Herein we describe an unusual phenomenon – darkening of the central nevus rather than lightening – following the appearance of the halo phenomenon. An 18-year-old boy who had multiple atypical nevi developed multiple halo nevi beginning at the age of 12 years. Following the appearance of the peripheral halos, 2 of his nevi that were originally solid medium brown in color darkened and the hyperpigmentation had a reticulated pattern with perifollicular sparing. One possible explanation is a postinflammatory hyperpigmentation induced by the infiltrating lymphocytes.

Strategies for early melanoma detection: Approaches to the patient with nevi

“…Targetoid or “cockade” nevi 86,87 exhibit concentric patterns of pigmentation usually consisting of central and peripheral pigmented areas with an intervening area of hypopigmentation. “Halo” nevi are in various stages of regression due to inflammation,88 and most commonly present as hypopigmented skin surrounding a pigmented lesion that progressively lightens over time, although darkening of the central lesion has also been described 89…”

Association of halo nevus/i and vitiligo in childhood: a retrospective observational study

“…Clinically the HN can develop in four different stages, as proposed by Huynh et al in 2001: brown nevus surrounded by a rim of depigmentation, the classic form of the HN (stage I), a loss of pigmentation of the nevus (stage II), disappearance of the central papule ⁄ macule leading to a round area of depigmentation (stage III) and finally a repigmentation of the depigmented area and disappearance of the halo (stage IV). 5 Not all HNi evolve through these last three stages but they can halt their development at any one of them. Some authors suggest that, even if the exact aetiology of halo phenomenon and vitiligo remains uncertain, a common immunologically mediated response to pigmented cells might be considered.…”

The natural history of halo nevi: A retrospective case series

“…26 Three patients in our study had a history of vitiligo. The association of HN with vitiligo is unclear, Adapted from Frank and Cohen 6 and Huynh et al 35 CI, Confidence interval. and they have been postulated to have different pathogenic mechanisms.…”