Medical Care
Halo nevi are benign, and no treatment is necessary.
Consultations
The chief diagnostic consideration in patients with halo nevi is melanoma that is undergoing regression, although making this distinction is not usually difficult. Primary melanoma is usually solitary, whereas halo nevi are commonly multiple. Furthermore, children are affected more commonly with halo nevi; adults are affected far more commonly by melanoma. Nevertheless, the risk of an individual lesion should be assessed based on both its history and clinical features as a whole. Any characteristic deemed suspicious for possible malignant behavior should be definitively addressed. [12]
Melanomas with surrounding white or hypopigmented zones usually have been present for an extended period of time, and the white areas represent zones of regression. Thus, the "halo" of a regressing melanoma is irregular in shape and variable in radial width, as opposed to the evenly distributed, circular zone of hypopigmentation in true halo nevi, which is distributed around the central nevus. Furthermore, melanomas usually exhibit the characteristic clinical signs of breadth, asymmetry, poor circumscription, and color irregularity with black foci that usually allow the diagnosis to be rendered with relative ease.
In spite of clinically benign features, the presence of a new "halo nevus" in an older adult should be regarded with a high index of suspicion for melanoma and may warrant performing a biopsy. In those patients where a potential malignancy is in question, a dermatologist should be consulted.
Complications
The course of halo nevi is normally uncomplicated. Problems arise in those instances where the lesions have been misdiagnosed or when the lesion is excised and wound complications develop postoperatively.
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Classic appearance of a halo nevus.
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Note the central pink papule (intradermal nevus) and the surrounding halo. The halo is of uniform width at all points, and no inflammatory component can be seen. Note the normal nevus directly inferior.
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At low magnification, a dome-shaped papular lesion reveals a dense infiltrate of lymphocytes in the dermis (hematoxylin and eosin, original magnification X40).
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Higher magnification reveals nests of nevus cells with numerous lymphocytes surrounding them and in the interstitium (hematoxylin and eosin, original magnification X40).
Tables
Halo Nevus |
Melanoma |
Nevus cells in nests |
Single atypical melanocytes at all levels of the epidermis and aggregates of atypical melanocytes in the dermis |
Lesion symmetrical |
Lesion asymmetrical |
Maturation of nevus cells |
Lack of maturation |
Mitotic figures rare or absent |
Mitotic figures present |
Lymphocytic infiltrate present diffusely throughout lesion |
Lymphocytic infiltrate tends to be at be concentrated at periphery |
