Arachnoid cyst of the lateral ventricle.

BACKGROUND

Arachnoid cysts rarely occur within the lateral ventricles, with only 10 reported cases in the literature. They may arise from the arachnoid layer that is present in the choroidal fissure.

CASE DESCRIPTION: This 25-year-old man with headache and a left jacksonian seizure had an intraventricular arachnoid cyst of the right occipital horn and trigone found on radiologic examination by computed tomography (CT) and magnetic resonance imaging (MRI). He was successfully treated by evacuation of the cyst and removal of its wall through a right parietooccipital craniotomy. Histologic studies of the cyst wall confirmed the presence of arachnoid cells and connective tissue.

CONCLUSIONS

Arachnoid cysts of the lateral ventricles occur in the occipital horns and trigone (all but 1 of 10 cases) in young patients with symptoms of intracranial hypertension. MRI well defines the relationship of the cyst with the ventricular wall. Surgical removal of the cyst wall or cystoperitoneal shunt have been successfully performed in the reported cases; however, endoscopic fenestration of the cyst must be considered today as the treatment of choice.