RESUMEN
Erdheim-Chester disease is a rare non-langerhans cell histiocytic disorder of an unknown cause that may associate with multisystem, rapidly fatal, infiltrative disease. We report here on a case of Erdheim-Chester disease in a 45-year-old man who presented with chronic renal failure. The patient visited a local clinic due to renal failure that was accidentally diagnosed on a routine health examination. At that time, abdominal computed tomography revealed retroperitoneal fibrosis and bilateral hydronephrosis. However, he did not visit hospital for further evaluation. After 1 year, he visited our clinic due to exertional dyspnea that had developed several months previously. The chest and abdominal CT showed interstitial pneumonitis and pleural effusion and there was progressed hydronephrosis and perirenal fibrosis. He was diagnosed with Erdheim-Chester disease based on the characteristic findings of pleural biopsy (interstitial fibrosis, infiltration of macrophge, CD68-positive but S-100 negative). The patient was treated with insertion of a double J catheter and immunesuppression with prednisolone and azathioprine. Erdheim-Chester disease is a rare disease, but it should be considered in those patients displaying chronic renal failure with retroperitoneal fibrosis.