Myelin oligodendrocyte glycoprotein antibody-associated diffuse orbital inflammation.

An 87-year-old man presented with a 2-day history of painful bilateral visual loss. On examination, exophthalmos, lid edema, chemosis, and optic disc edema, on the left side only, were found. Visual acuity was 4/10 OD and no light perception OS. Magnetic resonance imaging (MRI) revealed bilateral optic neuritis and a diffuse and severe infiltration of the intra- and extraconal fat on the left. Laboratory testing was negative except for serum myelin oligodendrocyte glycoprotein (MOG) antibodies. This presentation adds a new variant to the MOG-associated disease spectrum. Testing for MOG antibodies should be considered in patients presenting with diffuse orbital inflammation and optic neuritis.