MR findings in isolated oculomotor nerve palsy associated with infectious mononucleosis caused by Epstein-Barr virus infection.

A 20-year-old man presented with fever, bilateral swelling of the cervical and inguinal lymph nodes, and splenomegaly. Later he noted diplopia. CSF was unremarkable. High serum antibodies to Epstein-Barr virus (EBV) were discovered. MRI revealed an abnormal lesion in the right third cranial nerve, which was considered to be the pathological lesion associated with his clinically apparent oculomotor nerve dysfunction.