Generalized eruptive histiocytoma evolving into xanthoma disseminatum in a 4-year-old boy.

We report a 4-year-old boy who developed a generalized and symmetrical eruption of brownish papules over a period of 8 months, with spontaneous regression of some lesions. Clinical, histopathological and ultrastructural studies were suggestive of the diagnosis of generalized eruptive histiocytoma (GEH). The clinical features subsequently changed to a generalized eruption of confluent, yellowish papules, and diabetes insipidus developed. The clinical, histopathological and ultrastructural features of the new lesions were those of xanthoma disseminatum with cerebral involvement. This evolution suggests that GEH and xanthoma disseminatum may be variants of a continuous spectrum of histiocytic diseases.