Descriptive study of naevus involution in a series of 74 patients with atypical naevus syndrome under SIAscopy digital follow‐up

Abstract

Background Characterization of nevi involution could help to understand the biological behaviour of melanocytic neoplasms. Objective To describe the frequency and morphology of naevus involution in a series of patients with atypical naevus syndrome under digital follow-up with a SIAscopy program and, in a small sample of fading nevi, to analyse histopathological features and immunohistochemical biomarkers. Methods Seventy-four patients registered from April 2007 to July 2014 in the SIAscopy system of the Department of Dermatology of Hospital Arnau de Vilanova of Lleida, Spain, were reviewed. Fourteen naevus cases with fading features were prospectively excised during follow-up. Eleven already excised naevus controls were randomly selected from our archive. Results We observed that 81% of patients showed, at least, one involutive naevus and 25% of recorded nevi presented this phenomenon; the mean time of involution was 46.7 months. The predominant structural pattern was reticular (>70%), and the most frequently observed regression structures were vascular (33.8%). Histopathological significant higher intensity of inflammatory infiltrate in controls and higher presence of laminar and compact fibrosis and increase of vessels in cases were demonstrated. Regarding immunohistochemical biomarkers, only higher expression of cytoplasmic activated caspase 3 in controls was significant. Conclusions Naevus involution is a common phenomenon in patients with dysplastic naevus syndrome. It is usually a slow process, more frequent in naevus with reticular pattern. SIAscopy regression structures are uncommon, with the exception of vascular ones. Histologically, fading involutive pattern is characterized by scarce inflammatory infiltrate and melanophages, delicate fibrosis and increase of vessels.

The long‐term evolution of melanocytic nevi among high‐risk adults

“…However, this observation is important to incorporate into clinical practice as new melanocytic lesions are easily identified with the increasing use of TBP, but many are likely to be benign and not require biopsy. Unlike previous studies, 11 , 17 we observed a very limited number of disappearing nevi (max. 3), even in older participants.…”

“…The disappearance of nevi in the current study was not accompanied by a halo or apparent inflammation, suggesting the most common mechanism was fading pigment. 17 …”

“…The disappearance of nevi in the current study The Long-Term Evolution of Nevi was not accompanied by a halo or apparent inflammation, suggesting the most common mechanism was fading pigment. 17 Traits of nevus volatility are associated with each other. In the current study, patients with a higher baseline nevus count and a higher number of disappearing nevi were also more likely to have a higher number of new nevi.…”

“… 13 Furthermore, longitudinal studies have not correlated changes in nevus counts with patient and nevus factors. 9 , 11 , 14 , 15 , 16 , 17 A study that does not track individual nevi may ignore the possibility that different types of nevi may have different trajectories. An exogenous pathway of development, related to UV exposure, may apply to junctional nevi that peak in midlife and then regress.…”

“…An account for the conflicting data could be that the association between nevus counts and age is an artefact of cross‐sectional studies, and differences in ultraviolet radiation (UV) exposure across birth cohorts may explain the disparity in nevus counts by age 13 . Furthermore, longitudinal studies have not correlated changes in nevus counts with patient and nevus factors 9,11,14–17 . A study that does not track individual nevi may ignore the possibility that different types of nevi may have different trajectories.…”