Incidental Discovery of Perirenal Erdheim-Chester Disease During a Post-Traumatic CT Scan: A Case Report

Background

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis characterized by multisystem infiltration by CD68+/CD1a− foamy histiocytes. Retroperitoneal and perirenal involvement, known as "hairy kidney," is a hallmark of the disease, present in 50–68% of patients. Diagnosis is often delayed due to its nonspecific clinical and radiological presentation.