Equivocal Longitudinal Melanonychia in a 3-Year-Old Caucasian Girl: Rapid Evolution and Fading during Digital Dermoscopy Follow-Up

<b><i>Introduction:</i></b> Nail matrix nevi (NMN) in pediatric patients manifest as longitudinal melanonychia (LM) and can share clinical, dermoscopic, and histopathological characteristics with subungual melanoma. Equivocal findings in childhood LM may reflect dynamic processes during the natural life cycle of NMN in children. <b><i>Case Presentation:</i></b> We present a case of a heavily pigmented LM with equivocal clinical and dermoscopic findings in a 3-year-old Caucasian girl, which exhibited signs of evolution, maturation, and almost complete involution within a short time period during digital follow-up, attributed to the natural course of NMN. <b><i>Discussion/Conclusion:</i></b> Considering the rarity of subungual melanoma in childhood, our case underlines the significance of clinical and digital dermoscopy follow-up in the evaluation of childhood LM in order to avoid unnecessary biopsies and potential permanent nail dystrophy.