AJR 2004; 183:1253-1260.
Dion E, Graef C, Haroche J, Renard-Penna R, Cluzel P, Wechsler B, Piette JC, Grenier PA.
Erdheim-Chester disease is a rare form of non-Langerhans cell his-tiocytosis of unknown origin, belonging to the category of acquired overload histiocytosis. Erdheim-Chester disease is characterized by tissue infiltration by foamy histiocytes (xanthogranulomatosis) with im-munohistochemical characteristics different from those of Langerhans cell histiocytosis. Immunohistochemical stains are constantly positive for CD68 and negative for CD la, and ultrastructural studies show Birbeck granules in less than 20% of histiocytes. Staining of all histiocytic cells is negative or very weakly positive for S-100 protein.