Juvenile xanthogranulomas (JXG) are benign, spontaneously regressing histiocytic tumors of unknown pathogenesis. The incidence is unknown, and there may be a slight male preponderance.

JXGs are usually solitary and most often appear at birth or within the first year of life. However, their number and size may increase over the first 18 months of life. Lesions usually regress spontaneously over 3-6 years, leaving behind persistent pigmentary change or atrophy.

Systemic involvement is rare, with the most common site of extracutaneous involvement being the eye (0.3%-0.5%). Eye involvement is more common in patients with multiple JXGs. Many internal organs can potentially be involved, including the central nervous system, liver, lungs, muscles, oropharynx, and spleen. Cutaneous lesions are absent in one-half of cases with systemic involvement. JXG lesions are primarily driven by kinase-activating alterations in mitogen-activated protein kinase (MAPK). ALK translocations and BRAFV600E mutations have been detected in some patients with systemic JXG. 

JXGs have been associated with neurofibromatosis type 1 (NF1), particularly in patients younger than 2 years of age. Additionally, a triple association between JXGs, NF1, and juvenile myelomonocytic leukemia has been observed in several case reports.

JXGs can rarely occur in adults. Adult-onset xanthogranulomas persist longer and are more frequently associated with permanent changes in pigment and atrophy after spontaneous resolution.