22 year old with splenial lesion

A 22 year old woman presented with numbness on her left side upon awakening. The duration of the symptoms was about 20 minutes, after which she was neurologically normal. MRI showed a lesion completely contained within the splenium of the corpus callosum. The lesion had diffusion characteristics of acute stroke. MRA head and neck, MRV, MRI cervical and thoracic spine were all completely negative, as were visual evoked potentials. Spinal tap showed an elevated protein of 111, 146 wbc's and 4 rbc's. Oligoclonal banding was not present. MR spectroscopy done did not show a choline peak. The MRI shown is:

The syndrome of reversible splenial lesion, with complete clinical resolution, occurs in two principal settings. One is the rapid withdrawal of antiepileptic drugs, and the other is post influenza infection, occassionally other viruses such as mumps. The MRI features closely resemble acute stroke in terms of diffusion weighted abnormalities.