Giant partially thrombosed 4th ventricular posterior inferior cerebellar artery aneurysm; microsurgical management

A 42-year-old woman presented with a 3-month history of progressive occipital headache, vomiting, walking difficulty, and repeated fall. She had no history of sudden and severe headache. She had positive cerebellar signs, predominantly on the right side. Computerized tomography (CT) scan, CT angiogram, and magnetic resonance image (MRI) of the brain showed suspected partially thrombosed giant 4th ventricular posterior inferior cerebellar artery aneurysm. Patient developed severe hypersensitivity reaction during both CT scan and MRI after contrast injection. Though needed, digital subtraction angiogram (DSA) of cerebral vessels was not done. The aneurysm was managed by microsurgical clipping of the aneurysm neck and partial excision of thrombosed aneurysm. Here, we report the details of management of these difficult giant aneurysm without DSA.