Juvenile xanthogranuloma (JXG) is a benign, proliferative disorder of histiocytic cells of the dermal dendrocyte phenotype. JXG belongs to the broad group of non-Langerhans cell histiocytoses and is typically a disorder of early childhood. JXG typically presents in the first two years of life as a solitary, reddish or yellowish skin papule or nodule (picture 1D), most often on the head, neck, or upper trunk. Histologically, JXG is characterized by the presence of histiocytes, foam cells, and Touton giant cells. JXG generally follows a benign course with spontaneous resolution over a period of a few years. Less commonly skin lesions can be multiple (picture 2B). Extracutaneous or systemic forms are exceedingly rare and can be associated with considerable morbidity.
An overview of JXG will be presented here. Langerhans cell histiocytosis is discussed separately. (See "Clinical manifestations, pathologic features, and diagnosis of Langerhans cell histiocytosis" and "Langerhans cell histiocytosis (eosinophilic granuloma) of bone in children".)
JXG is the most common of the non-Langerhans cell histiocytoses . The incidence is unknown. In a large tumor registry spanning 35 years, JXG accounted for 129 of 24,600 pediatric tumors (0.5 percent) . However, this figure may be an underestimate of the relative frequency of JXG since many cases are diagnosed on clinical grounds without histologic confirmation. In a survey of 122 dermatologists with an average of 12 years of practice, 2371 cases of JXG were reported (an average of less than two cases per dermatologist per year); only 7 cases had ocular involvement .
JXG may be present at birth . The median ages of onset in two large case series were 5 months (range 0 to 244 months) and 1 year (range 0 to 20 years) [2,5]. The male to female ratio was about 1.4:1.
The prognosis of JXG is generally good, with spontaneous resolution of skin and organ lesions over a few years. Rare fatalities have been reported in infants with central nervous system or massive hepatic involvement [2,5-8]. (See 'Prognosis' below.)