Giant posterior inferior cerebellar artery (PICA) aneurysms are rare lesions carrying significant morbidity due to mass effect and present therapeutic challenges due to proximity to critical neurovascular structures.

A systematic literature review through the PubMed and Scopus databases was performed according to the PRISMA guidelines to identify cases of giant PICA aneurysms treated either microsurgically or by endovascular means. Patients’ demographics, aneurysm size, preoperative and postoperative neurologic status, clinical outcomes as well as follow-up information were retrieved.

Data from 24 studies including 24 patients was obtained. Mean patient age was 53.42 years, with a male-to-female ratio of approximately 1:2. Mean maximum aneurysm diameter was 33.43 mm. A favorable outcome (mRS 0–2) was reported on 66.7% of endovascular and 84.2% of microsurgical cases. Death rate was 0% for endovascular and 5.3% for open cases. The PICA was sacrificed in 33% of the patients without lasting morbidity. 87.5% of the aneurysms were partially thrombosed, 41.7% were debulked due to mass effect and 20.8% required a revascularization procedure.

Giant PICA aneurysms are amenable to both microsurgery and endovascular treatment. The latter may require PICA sacrifice which may be safely attempted in distal aneurysms. Proximal aneurysms which cannot be safely embolized or ones with significant mass effect may benefit from microsurgical occlusion and may require debulking and/or PICA bypass.