Central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) are osmotic demyelination syndrome. A 45-year-old man with a history of alcoholism visited the ER with dysarthria and dysphagia for 2 days. These symptoms occurred 3 days after he had stopped drinking alcohol. The neurological symptoms progressed to anarthria, pseudobulbar palsy and gait disturbance. During admission, the electrolyte studies were within the normal range. Diffusion-weighted images revealed high signal intensities in the pons, thalamus and basal ganglia. Apparent diffusion coefficient image showed low signal intensities in the pontine lesion, but isosignal intensities in the extrapontine lesion. The symptoms gradually improved after 1 month with only conservative treatment. The 1 month-follow-up MRI showed significant reduction of the previous extrapontine lesions. These findings suggest that cytotoxic edema is central to the pathogenesis of CPM, but vasogenic edema plays an important role in the pathogenesis of EPM occuring during alcohol withdrawal.