A rare case of Erdheim Chester disease.

Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis. There are few documented cases in the medical literature. Here, we present an infrequent case of a 53-year-old patient who presented with cutaneous xanthelasma and a gradual decline in general health characterized by asthenia, anorexia, and chronic dyspnea over the last 5 years. Chest, abdominal, and pelvic CT scans revealed distinct findings suggestive of ECD, including peri-renal fat infiltration resulting in the "hairy kidney" sign, hepatosplenomegaly, renal artery ostial stenosis, pneumopericardium thickening, interstitial lung parenchymal involvement, metaphyseal-diaphyseal osteosclerosis affecting long bones, and sinus osteosclerosis. A biopsy confirmed the diagnosis. This case highlights the importance of radiologists being familiar with the characteristic radiologic signs of ECD to avoid unnecessary repeat examinations, delays in diagnosis, or misdiagnosis.