Reversible posterior leukoencephalopathy syndrome (RPLS) is characterized radiographically by magnetic resonance imaging as white matter hyperintensities, which reflect cerebral edema. These changes are typically restricted to the parietal and occipital lobes, and are usually quite symmetric. We report a case of asymmetric RPLS involving only one frontal lobe in a patient with severe hypertension, chronic internal carotid artery stenosis, and ipsilateral vasogenic edema.