Nail Unit Blue Nevi: A 11-Case Series and Review of the Literature

Abstract

Background: Blue nevus of the nail apparatus is a rare entity and only isolated cases are reported in the literature. Objective: The aim of this study was to better characterize blue nevus at the nail unit. Methods: Retrospective analysis of all nail unit blue nevi from the Nail Group of the French Society of Dermatology was compared to the literature. Results: Eleven cases were retrieved from 2002 to 2019 with an average age of 45 years. The majority were women (9/11) and acquired (10/11). Hands were more frequently involved (9/11) with a predilection for the thumb and 2 cases were located on the hallux. Nail unit blue nevus mostly presented as a well-delimited blue spot of the lunula (9/11) and histologically was of the common type (10/11). There was no malignancy. Conclusion: Nail unit blue nevus is a rare asymptomatic benign entity, mostly acquired on the thumb or the hallux of women. The most frequent presentation is a painless blue spot on the lunula. Congenital blue nevi seem to only affect the paronychium. Main differential diagnosis is melanoma and histopathological examination is mandatory.