[Erdheim-Chester disease of the orbit with compressive optic neuropathy].

A 60-year-old man presented with left exophthalmos and deterioration in visual acuity of slow evolution. Bilateral orbital Erdheim-Chester disease was diagnosed. Systemic evaluation revealed a retroperitoneal fibrosis. Treatment with interferon-alpha followed, but bilateral compressive optic neuropathy with visual acuity deterioration and visual field defects evolved. Bilateral orbital decompression was performed.