A 38-year-old woman with a history of a granulomatous lesion of the nose, developed blurred vision, ataxic gait, and spastic tetraparesis. The presence of demyelination on the brain MRI led to the diagnosis of cerebral demyelination associated with Wegener's granulomatosis. Pulse cyclophosphamide administration resulted in some clinical of improvement of her condition. Demyelinating lesions seen in Wegener's have been ascribed to multiple sclerosis, but in this case, they are much more reminiscent of disseminated encephalomyelitis (DEM). The immunological challenge of the underlying disease, may, in the genetically susceptible person, presumably trigger the appearance of MS lesions. Wegener's granulomatosis must be considered in the differential diagnosis of MS.