HALO-NEVUS OR HALO PHENOMENON - A STUDY OF 142 CASES

One hundred and forty-two (142) halo nevi were reviewed. For 66 cases the diagnosis of halo nevus was made both clinically and pathologicall y, and for 76 cases the diagnosis was based on histological grounds al one. The nevi were classified by type and by degree of atypia. Of the 142 nevi, all were compound, junctional, or intradermal nevi except fo r one case of a Spitz nevus and two cases that could not be further cl assified. For those with a clinicopathological diagnosis of halo nevus , 11% exhibited moderate atypia; 16% exhibited minimal atypia to only focally moderate atypia; 24% minimal atypia; and 49% exhibited no sign ificant atypia. For those cases where the diagnosis was pathological o nly, there was also a broad spectrum of atypia identified, with 8% exh ibiting focally severe or severe atypia. This study supports the conce pt that the halo nevus should not be regarded as a single clinicopatho logical entity, but rather that the halo phenomenon occurs in a wide s pectrum of nevus types exhibiting a wide spectrum of histological atyp ia. The pathologist is therefore encouraged to classify halo nevi on t he basis of the nevus cell population alone, using whatever classifica tion normally utilized.