Midbrain infarction causing oculomotor nerve palsy and ipsilateral cerebellar ataxia.

We herein report the case of an 81-year-old woman with midbrain infarction causing pupil-sparing oculomotor nerve palsy with ipsilateral cerebellar ataxia. The lesion was located at the rostral end of the decussation of the superior cerebellar peduncle touching the dorsal side, further caudal and dorsal to causal lesions of Claude's syndrome, which presented as oculomotor palsy and contralateral cerebellar ataxia. This is the third report of midbrain infarction causing partial oculomotor nerve palsy with ipsilateral cerebellar ataxia. It may be possible to establish this entity as a new syndrome following the accumulation of more cases.