Halo nevi and melanoma.

Halo nevi may be associated with occult melanoma or may signify melanoma in a remote location. When a single halo nevus is present, the lesion should be biopsied to exclude melanoma. In addition, the patient's entire skin surface should be examined, and a careful ophthalmologic examination should be performed to exclude intraocular melanoma. Although the pathophysiologic relationship of halo nevus to melanoma is unclear, immunologic mechanisms have been postulated.