Erdheim-Chester disease (ECD) is a rare disease that includes sclerosis in the upper and lower extremities and extraskeletal involvement. No standard therapy exists, but interferon-α has helped some patients. The prognosis for patients with this condition is poor.
ECD is characterized by a symmetrical sclerosis at the diametaphyseal portions of the upper and lower extremities with additional extraskeletal involvement1 including the kidney and retroperitoneum, lung, pericardium, skin, orbit, and brain. Infiltration of the pituitary stalk may lead to diabetes insipidus2. Skeletal involvement is characteristically bilateral and symmetric, with a characteristic bone scan finding …