Clinically Mild Encephalitis/Encephalopathy with a Reversible Splenial Lesion without Central Nervous System Disturbances: A Case Report

Patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) on the splenium of the corpus callosum (SCC) present with relatively mild central nervous system disturbances. A 41-year-old man was admitted with fever and headache and, his main symptoms were mild headache and fatigue. There were no neurological focal signs. Brain magnetic resonance imaging (MRI) showed abnormal signals in SCC. We report, for the first time, a MERS patient, detected on MRI, who did not present with central nervous system disturbances. Our experience suggests MERS should be considered as a differential diagnosis in patients with fever of unknown origin.