Erdheim-Chester disease (Q67672)

Erdheim-Chester disease is a Class IIa (non-Langerhans cell) histiocytosis of unknown aetiology characterised by a xanthogranulomatous infiltration of viscera, bones, retroperitoneum and skin by lipid-laden histiocytes and surrounding fibrosis. It most commonly presents in adult life with bone pain, typically around the knees and ankles. Exophthalmos, diabetes insipidus, cutaneous xanthomata, pulmonary fibrosis and a broad range of complications resulting from retroperitoneal and CNS infiltration are all well recognised.