Extracranially located PICA aneurysm presenting with supratentorial IVH: A rare event with diagnostic pitfalls
A 16-year-old female presented with sudden onset severe headache followed by transient loss of consciousness but no neurological deficits. She developed vasospasm on post-ictus day 9 with paraparesis, which improved gradually. Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Magnetic Resonance Angiography (MRA) of the brain performed at a regional center revealed intraventicular hemorrhage (IVH) in the lateral and fourth ventricles but did not reveal any aneurysm or arteriovenous malformation []. The patient was referred to us after one month with severe headache and improving paraparesis. Repeat CT showed non-communicating hydrocephalus, and a four-vessel digital subtraction angiography (DSA) showed extracranially originating right PICA harbouring a 9.5 × 3.6 × 5.2 mm saccular aneurysm directed posteriorly with a neck measuring 2 mm at the level of C1, which was missed on the initial brain MRI; as the aneurysm was extracranial []. In view of the raised intracranial pressure because of the hydrocephalus, the patient underwent a right ventriculo-peritoneal shunt followed by right far lateral sub-occipital craniectomy with C1-C2 right hemi-laminectomy for clipping the extracranially placed PICA aneurysm. The patient recovered without any neurological deficits.