Erdheim-Chester disease: Typical radiologic findings of a multisystemic disease.

Erdheim-Chester disease is a rare and multisystemic entity. It results from the infiltration of tissues by foamy histiocytes. The etiology is unknown, but there are mutations in the MAPK pathway in over 80% of patients, more frequently BRAF mutation. The most commonly affected organs and systems are the skeleton, central nervous system, cardiovascular system, kidney, lungs, and skin. The most common clinical manifestations are bone pain, usually in the lower limbs, and diabetes insipidus. The diagnosis is challenging. It requires a combination of clinical, radiological, histopathological, and molecular findings. We present the case of a patient with typical clinical and radiological manifestations: bone pain and diabetes insipidus at presentation, bilateral long bone cortical sclerosis, hairy kidney appearance, coated aorta, right atrium pseudotumor, and periorbital masses.