AI Insight
A 63-year-old man previously diagnosed with unconfirmed sarcoidosis presented with persistent fever of unknown origin and was found to have massive bilateral perirenal infiltration consistent with Erdheim-Chester disease. Laboratory findings revealed microcytic anemia, significantly elevated inflammatory markers (C-reactive protein 173 mg/L), hypergammaglobulinemia, and a monoclonal IgG lambda component, while kidney function remained normal. This case highlights the diagnostic challenge of Erdheim-Chester disease, a rare non-Langerhans cell histiocytosis that can mimic other systemic conditions.
Why it matters
This case emphasizes the importance of histological confirmation in suspected systemic diseases, as the initial sarcoidosis diagnosis was incorrect. Erdheim-Chester disease requires different treatment approaches than sarcoidosis, and early accurate diagnosis can prevent delayed appropriate therapy and potential organ damage from this rare histiocytic disorder.
Understand the Science
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).
Source: [Clinical Rounds] Massive bilateral perirenal infiltration in Erdheim-Chester disease