Claude's syndrome associated with supranuclear horizontal gaze palsy caused by dorsomedial midbrain infarction.

Claude's syndrome caused by dorsal midbrain lesion is characterized by ipsilateral third nerve palsy and contralateral ataxia. To date, reports in the literature concerning Claude's syndrome associated with the midbrain paresis of horizontal gaze are rare. A 62-year-old man suddenly developed left third cranial nerve palsy, right lateral gaze palsy, and right ataxia. Intact Bell's phenomenon and preserved right horizontal oculocephalic reflex suggested the lateral gaze palsy in the right eye was supranuclear in nature. Magnetic resonance imaging (MRI) revealed an infarction in the left dorsomedial midbrain. Although the red nucleus has often been suggested as the lesion site responsible for Claude's syndrome, a lesion of the superior cerebellar peduncle just below and medial to the red nucleus could be responsible for this syndrome. This case demonstrates neurological heterogeneity of midbrain infarction.