Challenges in diagnosis of Erdheim-chester disease: a case report

<div><strong>Background:</strong> Erdheim-Chester disease is a rare non-Langerhans cell histiocytosis characterized by the infiltration of lipid-laden macrophages into various tissues, leading to diverse clinical manifestations.</div> <div><strong>Case Presentation: </strong>A 53-year-old male presented with a history of recurrent flank pain and obstructive uropathy over seven years, which led to multiple imaging studies and treatments for bilateral renal stones. Recent imaging, including a CT scan of the abdomen and pelvis, revealed bilateral perirenal soft tissue thickening extending into the renal sinus and pelvicalyceal systems, moderate hydronephrosis, and bilateral renal stones, suggestive of ECD. A CT-guided biopsy of the perinephric soft tissue confirmed the diagnosis. Histopathological analysis showed fibrofatty tissue with histiocytes exhibiting foamy cytoplasm, lymphocytes, plasma cells, and Touton cells. Immunohistochemistry stains were positive for Factor 13A and CD68 in histiocytes, confirming ECD.</div> <div><strong>Conclusion: </strong>This case underscores the importance of considering ECD in patients with unexplained recurrent flank pain and renal abnormalities. Early recognition and biopsy are crucial for accurate diagnosis and management of this rare disease. The successful identification of ECD in this patient illustrates the critical role of advanced imaging and histopathological evaluation in diagnosing rare conditions.</div>