Atypical Posterior Reversible Encephalopathy Syndrome as the First Presentation of a Pheochromocytoma: A Case Report

Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiological entity that is manifested by characteristic magnetic resonance imaging (MRI) depictions of subcortical/cortical hyperintensities in the parieto-occipital lobes. Paroxysmal hypertension, headache, and palpitation are the most common clinical manifestations of pheochromocytoma, which are catecholamine-secreting enterochromaffin tumors. PRES is a rare complication of pheochromocytoma. Herein, we describe a 44-year-old woman who presented with postoperative confusion and headache. MRI images showed multiple asymmetrical hyperintensities with surrounding edema and contrast enhancement, predominantly in the right parietal lobe, left cerebellar hemisphere, and dentate nuclei, in favor of hemorrhagic metastases. The results of further investigations, including abdominopelvic computed tomography and the 24-hour urine test for metanephrine and normetanephrine, were in favor of a pheochromocytoma. The patient was scheduled for adrenalectomy and histopathologic examination of the tissue, which confirmed the diagnosis. Surprisingly, her symptoms and neuroimaging abnormalities improved significantly without any treatment during the follow-up period. Based on these findings, the diagnosis of PRES was considered and the patient was followed. She was symptom-free at 3 years’ follow-up. The literature contains only four case reports of PRES as a complication of pheochromocytoma; however, all these cases had bilateral symmetrical hemispheric involvement and occurred during childhood and adolescence.