Abstract
Background: It is rare for hypertensive encephalopathy to have isolated involvement in the brainstem without concomitant parietooccipital cortical lesions. We here described a case of a man whose MRI T2-weighted images mimicked brainstem tumor.
Case Report: A 41-year-old man developed blurred vision and only mild heavy-headedness. Soon after that, he was shown to have extreme hypertension of 260/110 mmHg at a local clinic. On admission to our hospital, neurological examination showed complete normal findings including the cranial nerves. MRI scans revealed T2 elongated lesions in the midbrain cerebral peduncles, pons, and cerebellar peduncles, whereas in the cerebral hemisphere only mild ischemic changes were noted, by all of which he was once suspected as having brainstem tumor. However, diffusion tensor images clearly showed normal fiber integrity. All these clinical features prompted a correct diagnosis of brainstem hypertensive encephalopathy. Ophthalmologic examination showed retinal bleeding. His blurred vision and mild heavy-headedness disappeared soon after his blood pressure was lowered by intravenous administration of nicardipine. At day 12 he was discharged from hospital.
Conclusions: In this case, normal diffusion tensor images are thought to help differentiating hypertensive encephalopathy from brainstem tumor, which corresponded to completely normal neurological findings.

Keywords: Hypertensive Encephalopathy, brainstem, diffusion tensor imaging