視野障害から明らかとなった視交叉症候群の検討

Cases of optic chiasmal syndrome with visual field defect as the initial manifestation

要約　背景：視交叉近傍の病変では両耳側半盲だけでなく，多彩な視野障害が生じるので，診断が容易でない。目的：視野異常の精査に磁気共鳴画像検査（MRI）を行い，視交叉症候群と診断した症例の報告。対象と方法：視野障害がある37例を対象とし，MRIで頭蓋内病変を検索した。結果：視交叉症候群であることが16例で判明した。男性5例，女性11例で，年齢は25～83歳（平均64歳）であった。疾患の内訳は，下垂体腺腫4例，Rathke囊胞3例，鞍結節髄膜腫2例，empty sella症候群2例などである。16例中9例に四半盲または半盲があったが，両耳側半盲または四半盲は4例のみであった。結論：視交叉症候群では多彩な視野障害が生じる。MRI検査は本症候群の診断に有用である。

Abstract.　Background：Diagnosis of chiasmal syndrome is difficult as the patient may manifest variable visual field disorders other than bitemporal hemianopia. Purpose：To report cases who had visual field defects and who were eventually diagnosed with chiasmal syndrome after examination with magnetic resonance imaging（MRI）. Cases and Method：Thirty-seven patients presented with visual anomalies. They were examined by MRI to detect intracranial lesions. Results：Sixteen cases were diagnosed with chiasmal syndrome. The series comprised 5 males and 11 females. The age ranged from 25 to 83 years,average 64 years. Chiasmal syndrome was due to pituitary adenoma 4 cases,Rathke cleft cyst 3 cases,tuberculum sellae meningioma 2 cases,and empty sella syndrome 2 cases. Nine cases showed hemianopia or quadrantanopia which was bitemporal in 4 cases only. Conclusion：MRI was useful in identifying chiasmal syndrome in patients with visual field defects.