Infratentorial cerebral proliferative angiopathy: A rare entity with high risk of hemorrhage.

Background: Cerebral proliferative angiopathy (CPA) is a rare vascular disease characterized by nonfocal angiogenic activity. Numerous case reports have been published; however, despite there are a few reported cases of infratentorial CPA (or cerebellar proliferative angiopathy), no comprehensive review of this condition has been conducted. Case Description: We report two cases of infratentorial CPA, and both of them presented intracranial hemorrhage. The first case was a 48-year-old woman with an incidentally detected vascular abnormality in the cerebellum, which remained stable for 11 years before presenting with subarachnoid hemorrhage. The second case was a 5-year-old girl who presented with a sudden headache and decreased consciousness. Digital subtraction angiography was performed in both cases, but the source of hemorrhage remained unidentified, and conservative management was chosen. Conclusion: A review of previously reported infratentorial CPA cases suggests that infratentorial CPA has a significantly higher risk of hemorrhage than supratentorial CPA. However, the risk of rebleeding appears to be low. Our findings highlight the need for further research to determine the optimal management strategies for this rare entity.