Weber症候群に同側視床中脳境界部病変による核上性垂直性眼球運動障害を合併した1症例

A Case Report of Weber's Syndrome Associated with Supranuclear Vertical Gaze Palsy Caused by the Ipsilateral Thalamomesencephalic Lesion

　症例は53歳の女性で，突然の意識障害と左上下肢の脱力で発症。神経学的には右側動眼神経麻痺，両側垂直性眼球運動障害，輻輳麻痺および左片麻痺が認められたが，左眼の水平性眼球運動や内眼筋は障害されておらず，vestibulo-ocular renexも保たれていた。MRIにおいて，右側の大脳脚および同側のmediallongitudinal fasciculusのrostral interstitial nucleus（riMLF）（吻側内側縦束間質核）に病変を認めた。本症例はWeber症候群に同側riMLF障害による核上性垂直性眼球運動障害を合併した症例で，現在のところ，このような報告はみられず極めて稀な症例と考えられた。最近の報告でいわれている一側riMLF障害により核上性垂直性眼球運動障害を呈することを再確認するとともに，MRIの有用性を強調したい。

We report a rare case showing Weber's syndrome associated with supranuclear vertical gaze palsy caused by the ipsilateral lesion of the rostra] inter-stitial nucleus of the medial longitudinal fasciculus (riMLF), which is regarded as the supranuclear control center of vertical gaze. To date, no litera-ture concerning Weber's syndrome assosiated with the ipsilateral riMLF lesion was documented.

The patient was a 53-year-old female, who sud-denly developed unconsciousness and left-sided weakness. Neurological findings on admission revealed right third nerve palsy, severe supranu-clear vertical gaze palsy, almost complete conver-gence palsy, left hemiparesis and hyperreflexia with positive Babinski's sign on the left side. There was no sign of pupillary disturbance or no abnormality of the horizontal movements of the left eye. The vestibulo-ocular reflex of the left eye was preser-ved. There was no sensory disturbance.

Cranial MRI had the advantages in demostrating unilateral ischemic lesions at the cerebral peduncle and the thalamomesencephalic junction involving the unilateral riMLF on the right side.

Recent reports have demonstrated that supranu-clear vertical gaze palsy is caused by the unilateral riMLF lesion. We confirm that the unilateral riMLF lesion causes supranuclear vertical gaze palsy in our case and that cranial MRI has the advantages in demonstrating the specific lesion.