We report the clinical, imaging, and laboratory features of 8 patients with Devic's neuromyelitis optica. All patients had severe myelopathy and optic neuritis. In no patient was the brain, the brainstem, or the cerebellum affected, even after several years of disease. Various immunosuppressive treatments failed to benefit the patients, 5 of whom died. Autopsies of these 5 patients demonstrated a severe necrotizing myelopathy with thickening of blood vessel walls and no lymphocyte infiltrates. In the appropriate clinical setting, the lack of white matter abnormalities demonstrated by magnetic resonance imaging of the head facilitates the recognition of Devic's syndrome during life. Inasmuch as Devic's myelopathy is necrotizing, rather than demyelinating, the prognosis of this syndrome is poor.