A patient with an 8-month history of chronic progressive visual loss was referred to the Neuro-ophthalmology Consult Office of Washington University with a diagnosis of chronic optic neuritis. Previous diagnostic studies, including CAT scan, had been negative. Because chronic progressive visual loss is considered a hallmark of mass lesion, more vigorous investigation, including repeat CAT scans, was undertaken, leading to the diagnosis and removal of a 2 cm meningioma.