Erdheim-Chester disease (ECD) is a rare, non-Langerhan’s cell histiocytosis characterized by tissue infiltration of CD68-positive and CD1a-negative foamy histiocytes.1 ECD was discovered as a lipid granulomatosis in 1930 by Jakob Erdheim and his pupil, William Chester, and approximately 500 cases have been described to date.1 ECD has a heterogeneous course and prognosis ranging from an…
