[Clinical Rounds] Massive bilateral perirenal infiltration in Erdheim-Chester disease

Abstract

A 63-year-old man with a reported history of sarcoidosis, without histological confirmation, was referred for evaluation of persistent fever of unknown origin. Laboratory investigations showed microcytic anaemia (haemoglobin 9·1 g/dL, mean corpuscular volume 70 fL), elevated C-reactive protein (173 mg/L), hypergamma-globulinaemia (23% of total gamma globulins), and a trace monoclonal IgG λ component. Kidney function was normal (serum creatinine 0·7 mg/dL, estimated glomerular filtration rate 97 mL/min per 1·73 m2).