Brown-Séquard型神経症状にて発症した胸髄くも膜嚢胞の1例

Thoracic Arachnoid Cyst Presenting Incomplete Features of Brown-Séquard syndrome : a case report

I．はじめに

　脊髄くも膜嚢胞は比較的稀な疾患で，他の脊髄疾患と同様に両下肢麻痺・感覚障害にて発症してくる報告がほとんどである．今回われわれはBrown-Séquard型神経症状にて発症した胸髄くも膜嚢胞の1例を経験したので若干の考察を加えて報告する．

Spinal intradural arachnoid cyst presenting incomplete features of Brown-Sequard syndrome is very rare. Only 6 cases have been reported. We report one in a thoracic lesion. A 42-year-old man noticed thermo-hypesthesia in his right leg, and monoparesis in his left leg. On admission, he presented incomplete fea-tures of Brown-Séquard syndrome below the Th7 level. MRI showed the spinal cord to be displaced antero-laterally to the right at Th6 - 7 level. Myelography and CT myelography failed to show the cyst wall, butan arachnoid cyst was totally removed with T5 - 8 osteoplastic laminotomy. Sensory disturbance has notchanged postoperatively, but motor weakness in his left leg recovered within one month after the opera-tion. No cystic lesion has been detected by MRI during the ten months since the operation. We investi-gated all seven cases in the literature including our case which showed incomplete features of Brown-S6-guard syndrome. As regards to the location of the cyst, all cases were at the mid-thoracic level. And fourcases were at the midline. These results suggest that the mechanism of Brown-Sequarcl syndrome associ-ated with spinal arachnoid cyst may be related not only to the laterality of the lesion but also to the asym-metrical circulation in the watershed area.