Posterior reversible encephalopathy syndrome associated with hypertension rarely presents with predominant involvement of the brainstem and is relative sparing of the supratentorial regions. A relative paucity of brainstem signs and symptoms, despite extensive neuroimaging abnormalities therein, support the diagnosis. Although elevation of blood pressure is common in acute cerebral infarction, concomitant brainstem edema has not been reported. We describe here the clinical and neuroimaging features of an unusual brainstem hyperintensity associated with acute ischemic stroke. The neuroimaging abnormalities improved after stabilization of blood pressure, distinguishing this syndrome from brainstem infarction.