Agminated, Eruptive Nevi in Patients With a History of Langerhans Cell Histiocytosis.

This multicenter, descriptive, retrospective study conducted at four centers aimed to describe the clinical, histological, and/or genetic characteristics and clinical course of pediatric patients with a history of Langerhans cell histiocytosis (LCH) who later developed eruptive melanocytic nevi from 2003 to 2023. Of seven patients diagnosed with LCH (average age of 18 months, range 0-96), five patients showed multisystem involvement affecting low-risk organs, while two presented with single-system disease localized to the skin. Agminated eruptive melanocytic nevi developed at an average of 48 months (SD ± 27.37) after initial LCH diagnosis, predominating on the trunk, groin, and upper extremities (in three patients at sites of previous LCH lesions). Agminated eruptive melanocytic nevi may appear in patients with LCH; further research is required to achieve a more comprehensive understanding.