Juvenile xanthogranuloma (JXG) is a histiocytosis that occurs in children and adolescents. It primarily affects the skin, but in rare circumstances it can affect other areas, including the bones, the area behind the eyes, and the brain. JXG that is localized to the skin can occur in infants. When this happens, it usually goes away on its own. Adult xanthogranuloma is a similar histiocytosis that affects adults.