脑室内蛛网膜囊肿罕见。作者报导1例: 患儿,8个月,男。因生后7个月时发现头围增大,发育迟缓而入院。患儿足月顺产,出生时身高,体重及头围正常,3月时抬头。检查见身高体重正常,头围增大达51cm,前囱隆起,不能坐起,并有右侧轻偏瘫。脑血管造影示脑积水,CT见两侧脑室扩大,左侧脑室有一密度较高之圆形病变,无对比增强,疑有室间孔阻塞,诊断为左侧脑室内皮样囊肿而作开颅手术。术中证实囊肿阻塞室间孔,囊肿有蛛网膜样被膜,囊液黄变,球蛋白反应与色 Intracranial arachnoid cysts are rare. The author reported 1 case: Children, 8 months, male. Due to an increase in head circumference at 7 months after birth, she was admitted to hospital with stunted growth. The children had full-term delivery, height at birth, weight and head circumference were normal, and they looked up in March. Check to see normal height and weight, head circumference increased up to 51cm, the front windmill uplift, can not sit up, and right hemi-paralysis. Cerebral angiography showed hydrocephalus. CT showed enlargement of ventricles on both sides. The left ventricle had a round lesion with high density. There was no contrast enhancement. There was a suspected obstruction of the interventricular hole. The diagnosis was a left intraventricular dermoid cyst and a craniotomy was made. surgery. Intraoperative confirmation of cysts blocking the interventricular pores, cysts with arachnoid-like capsules, cyst fluid yellowing, globulin reaction and color