In vivo reflectance confocal microscopy of halo nevi.

Background: Halo nevi named also Sutton's nevi are uncommon melanocytic lesions occurring especially among adolescents. There are two effective diagnostic methods: dermoscopy and in vivo reflectance confocal microscopy (RCM), which can help us to observe many structural elements and characteristic features of Sutton's nevi.

Objective: The aim of this study was to describe reflectance confocal microscopy features of halo nevi.

Methods: Eleven patients with fourteen halo nevi were examined by FotoFinder Medicam 800 dermoscope and reflectance confocal microscope Viva Scope 1500 between May of 2018 and September of 2019.

Results: Dermoscopic examination revealed 78.6% nevi with a globular pattern, while 21.4% showed a homogenous pattern. In RCM, a typical honeycombed pattern was observed in 57.1% of nevi. 42.9% of nevi showed a disarray of the epidermis and presence of dendritic cells. 35.7% of all lesions presented roundish atypical cells in the epidermis. Roundish pagetoid cells in the dermo-epidermal junction were detected in 14.2% of nevi. Non-edged papillae were observed in 50% of lesions. In each nevus, there were dilated vessels. 50% of nevi revealed dense nests in the periphery, although in case of one lesion the dishomogeneous nests were observed.

Conclusions: Halo nevi are important "melanoma simulators" in confocal microscopy.