[A case of Nothnagel syndrome].

A 72-year-old woman developed a sudden onset of bilateral ptosis, diplopia and gait disturbance. Neurological examination revealed bilateral oculomotor palsies, truncal ataxia, and transient slight weakness in the right upper extremity. She was diagnosed to have Nothnagel syndrome. T2-weighted MRI disclosed a high signal intensity lesion at the left paracentral portion of the upper midbrain in addition to the bilateral medial thalamic lesions, while brain CT showed only the thalamic lesions. Brain MRI was useful for detecting the small midbrain lesion.