Acute hemorrhagic leukoencephalitis is a fulminant demyelinating disease and commonly considered as a rare and severe variant of acute disseminated encephalomyelitis. Here, we report the clinical, magnetic resonance imaging, and brain biopsy findings of a 35-year-old female with relapsing-remitting multiple sclerosis, who developed acute hemorrhagic leukoencephalitis. Magnetic resonance imaging revealed symmetrical hemorrhagic lesions in the basal ganglia including the thalami. Disease progression was consistent with acute hemorrhagic leukoencephalitis with rapid deterioration of consciousness and seizures. Besides hemorrhage, infiltration of neutrophils was detected in brain biopsy.Acute hemorrhagic leukoencephalitis, also known as Weston-Hurst syndrome, is an excessive immunological response of unknown etiology. So far, an association with multiple sclerosis has not been reported. The present case raises the question, whether acute hemorrhagic leukoencephalitis is a specific hyperacute form of acute disseminated encephalomyelitis, a severe and unspecific form of an immune response in the central nervous system, or belongs to the spectrum of tumefactive multiple sclerosis.