Coexistence of ruptured basilar artery perforator aneurysm undetected on initial angiogram and unruptured anterior cerebral artery saccular aneurysm: Case report and literature review

Ruptured basilar artery perforator aneurysm (BAPA) is a rare cause of subarachnoid hemorrhage (SAH) and is difficult to diagnose.

A 60-year-old male was rushed to our hospital due to severe headache. Computed tomography (CT) showed diffuse SAH, and 3-dimensional CT angiography (CTA) showed a saccular aneurysm in the left anterior cerebral artery (ACA), which was treated with clipping. However, intraoperative findings showed little SAH around the aneurysm and neither a rupture point nor a white thrombus on the aneurysm. Postoperative CT showed a marked decrease in SAH in the prepontine cistern, and digital subtraction angiography (DSA) showed disappearance of the ACA aneurysm and no other lesions. SAH in the prepontine cistern re-increased on CT on the 6th postoperative day, when CTA failed to show the cause. On the 12th postoperative day, CT showed further increased SAH in the prepontine cistern, and DSA revealed a BAPA. Stent-assisted coil embolization was planned at the chronic phase, but the patient went into cardiac arrest the next day, presumably due to a third re-rupture of the BAPA.

The coexistence of a ruptured BAPA and an unruptured saccular aneurysm is extremely challenging in terms of both diagnosis and treatment strategy.