The spectrum of clinical manifestations of multiple sclerosis (MS) may include rare cases where cerebral lesions simulate brain tumors or abscesses on neuroimaging. We report here on a 43-year-old woman with numerous ring-enhancing cystic lesions in the white matter of cerebral hemispheres, brainstem and cerebellum. The radiological picture was overwhelmingly in favor of a metastatic or infectious etiology, but brain biopsy showed subacute demyelination with central necrosis.