Morphological features of melanocytic tumors with depigmented halo: review of the literature and personal results.

Halo (Sutton's) phenomenon has been described as a depigmented halo that is associated most commonly with acquired melanocytic nevi; but it may be associated with various types of melanocytic skin tumors, melanoma being the most concerning. Different authors have been preoccupied with elucidating morphological features of melanocytic tumors associated with a depigmented halo. We reviewed the literature and discussed the main features of melanocytic halo tumors regarding histopathological, immune microenvironment profile and dermatoscopic appearance. We highlighted similarities and differences between Sutton's nevus and halo melanoma, also presenting relevant aspects of our results. Depigmented halo must be regarded as a phenomenon that may be associated with different types of melanocytic tumors and with a broad spectrum of histopathological atypia degree. Certain correlations between the shape, diameter, symmetry observed in clinical examination, histopathological appearance, dermatoscopic aspect of peritumoral halo and central tumor type could not be established due to insufficient data and contrasting results. Further studies are expected to add valuable information regarding the depigmented halo tumors features.