Xanthoma disseminatum. An unusual histiocytosis syndrome

The histiocytoses are a diverse group of illnesses that present a variety of diagnostic and therapeutic dilemmas. In this article, we describe the case of an 8-year-old boy with xanthoma disseminatum, a histiocytic disorder involving the skin, eyes, and brain. In our discussion, we have emphasized the clinical, pathologic, and radiographic features that distinguish this entity from clinically similar juvenile xanthogranuloma and Langerhans' cell histiocytoses (histiocytosis X) such as the Hand-Schuller-Christian syndrome. The importance of differentiating the various histiocytoses, in view of their varying natural histories and therapeutic responsiveness, is reviewed in relation to the new classification system for these disorders proposed by the Histiocyte Society.