Subarachnoid and Intraventricular Hemorrhage in a Patient with a Pure Arterial Malformation and Two Associated Aneurysms in the Posterior Inferior Cerebellar Artery: A Case Report and Literature Review.

Introduction: Pure arterial malformations (PAMs) are rare vascular abnormalities defined as dilated, tortuous arterial loops without any associated venous compartment. PAMs are thought to be benign developmental anomalies that can be safely managed conservatively.

Methods: We present a case of life-threatening hemorrhage in a patient with a PAM associated with two aneurysms and review the literature describing hemorrhages associated with PAMs.

Results: A 65-year-old female presented with subarachnoid and intraventricular hemorrhage. A digital subtraction angiography revealed a posterior inferior cerebellar artery PAM associated with two saccular aneurysms, which were subsequently microsurgically clipped. At the 1-year follow-up, the patient was neurologically intact. In our literature review, we identified 21 papers describing a total of 37 PAMs. Patients were predominantly female (64.9%) and their median age was 35 years. Almost half (48.6%) of PAMs were associated with aneurysms. In the group of PAMs that were not associated with an aneurysm, the intracranial hemorrhage rate was 15.8%, while in cases of coexisting PAM and aneurysm it was 44.4% (p = 0.0789).

Conclusions: PAM natural history remains unknown, particularly in cases of coexistence with aneurysms. Patients so affected require careful observation. The description of PAMs as benign vascular malformations should be revised. Surgical management of hemorrhagic PAMs coexisting with aneurysms is possible and should be considered.