Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis characterized by the infiltration of bone and multiple organs by foamy lipid-laden histiocytes. ECD is easy to be misdiagnosed due to its complicated clinical manifestations. We report a patient who visited the hospital due to hypothalamic dysfunction, with central nervous system, pancreas, and lower limb bones involvements. Together with the evidence of clinical manifestations, imaging and pathology, this patient was diagnosed with ECD. After treatment with interferon-α, both the clinical symptoms and imaging manifestations of this patient were significantly improved.