SYMPTOMATIC INTRAVENTRICULAR ARACHNOID CYST IN AN ELDERLY MAN

A case of intraventricular arachnoid cyst in an elderly man is reporte d. A 63-year-old man developed a progressive gait disturbance over a G ive-year period. CT scan showed a large cyst in the left lateral ventr icle which was negative to contrast enhancement. CT cisternography rev ealed gradual accumulation and more than 48 hours retention of contras t medium in the cyst. The patient underwent left frontal craniotomy, a nd the cyst wall was partially resected for histopathological examinat ion. Although limit microscopic examination could not establish a diag nosis, arachnoid cyst was diagnosed by electron microscopic findings. Biochemical analysis did not detect any difference between cyst fluid and CSF obtained during surgery. It is suggested that a ball-valve mec hanism caused progressive enlargement of the cyst and gradual developm ent of symptoms in this elderly patient.