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Background Symptomatic cysts of epithelial origin occurring in the fourth ventricle are very rare. When such a cyst is encountered, the treatment strategy includes surgical removal or fenestration of the cyst into subarachnoid space. Case 1 A 23-year-old male was diagnosed as having a cyst located in the fourth ventricle causing hydrocephalus; the patient underwent cyst removal via craniotomy. The histopathologic diagnosis was neuroepithelial cyst. Because clinical and neuroradiological findings persisted, he underwent VP shunting. The cyst disappeared and did not recur. Case 2 A 54-year-old woman was diagnosed as having a cystic mass in the fourth ventricle and dilatation of the ventricles. Magnetic resonance imaging showed the same findings as those of the first case. The patient refused craniotomy for total mass excision. Therefore, a VP shunt was applied. Postoperatively, the clinical findings and hydrocephalus improved, and complete disappearance of the cystic mass was observed unexpectedly. Both cases had 2 years of follow-up. Conclusion There is no proven mechanism to explain resolution of fourth ventricle cysts after a supratentorial VP shunting. We hypothesize that disappearance of the cyst could result from rupture of its wall because of pressure gradient, which might be facilitated by a VP shunt. The current report should not be taken as an argument against cyst removal, which is the established way of treatment. However, considering that the pathogenesis and pathophysiology of these cysts are unclear, VP shunting should be considered especially for recurrent cases accompanied by hydrocephalus.

It has been shown that a long-acting angiotensin-converting enzyme inhibitor cilazapril prevents morphologic changes in arteries secondary to hypertension and endothelial damage, which are analogous to the changes in cerebral arteries following subarachnoid hemorrhage. In this study, the effect of cilazapril on chronic vasospasm was investigated on the rat femoral artery vasospasm model, and morphometric analyses were performed. Animals were divided into three groups. In group 1, femoral arteries were removed after cardiac perfusion. In groups 2 and 3, right femoral arteries were exposed to 0.1 mL autologous whole blood and wrapped with silastic cuff. Animals in group 3 received cilazapril (10 mg/kg) for 7 consecutive days. After the perfusion-fixation, femoral arteries were examined by light and transmission electron microscopy and processed for morphometric analysis. Vessels from animals in group 2 showed a significant luminal narrowing and morphologic changes throughout the vessel wall, while vessels from animals treated with cilazapril appeared nearly normal. These results suggest that cilazapril may be effective in the prevention of chronic vasospasm.