右側海馬腫瘍により記憶障害を示した1例

A Case with Disturbance of Memory caused by the Right Hippocampus Tumor

　抄録　37歳，男性。てんかんの鈎回発作で始まり，4年後に記銘・記億障害が出現したものである。原因は右側の海馬の腫瘍であった。現在まで一側性の海馬の障害では症状の発現はほとんど認められないとされてきた。しかし，本症例では一側の障害によって記銘・記憶力の障害が発現したことが注目された。このことから，一側の海馬の障害によっても症状が発現するか，あるいは一側優位が存在するのではないかと考えられた。

　ヒトの海馬に原発する腫瘍例は稀であることから本症例は辺縁系における記銘・記憶の機能を考える上で貴重な症例と思われた。

　The patient was a 37-year-old man. At the age of 34, he had uncinate fits of epilepsy and 4 years after the onset, his memory became disturbed. These symptoms were caused by a tumor of the right hippocampus.

　Up today, it has been insisted that a lesion of the lateral part of the hippocampus only doesn't bring about any psychiatric abnormalities. How-ever, in the present case there were symptoms of memory disturbance. This led us to consider two possibilities : Either disturbance of memory can be brought about through damage to the lateral part of the hippocampus, or there is a dominant side in the functioning of the hippocampus.

　This is a very rare case of a person who had primary tumor on the hippocampus itself. For this reason, the present case might offer an im-portant suggestion concerning the function of the hippocampus in the brain.