[Descriptive dermoscopic study of depigmentation in melanocytic nevi without a visible halo]

There are few cases described in the literature in which depigmentation of melanocytic nevi occurs without the appearance of halos. The aim of this study was to analyze the correlation between clinical and dermoscopic findings and to assess the usefulness of dermoscopy to identify possible markers of complete regression in melanocytic lesions.

A prospective, observational, descriptive study of 77 melanocytic lesions in 52 patients was undertaken over a 5-year period. Melanocytic lesions from patients who underwent periodic follow-up in the digital dermoscopy unit were analyzed if they had exhibited partial or total, permanent depigmentation without a clinically apparent halo.

We observed substantial variation in the time taken for pigmentation to disappear and the morphological characteristics of the nevi during the depigmentation process. Female sex and dermoscopic evidence of melanophage activity or of a halo were all associated with more rapid involution of pigmented lesions. The only variable which displayed a statistically significant association with complete depigmentation of melanocytic nevi was the presence of vascular proliferation. Fibrosis was the only variable that displayed a statistically significant association with heterogeneous depigmentation of melanocytic nevi.

In this study, we have identified patterns of depigmentation in melanocytic lesions that differ from the classic halo nevus.