Aneurysm of the anterior inferior cerebellar artery-posterior inferior cerebellar artery variant: Case report with anatomical description in the cadaver

OBJECTIVE AND IMPORTANCE: The authors report a very rare case of an aneurysm at the distal segment of the anterior inferior cerebellar artery-posterior inferior cerebellar artery (AICA-PICA) variant along with a description of the surgical anatomy of this variation in a cadaveric specimen. CLINICAL PRESENTATION: A 44-year-old woman experienced the sudden onset of severe headache and vomiting. Computed tomographic scanning revealed subarachnoid and intraventricular hemorrhage. Cerebral angiography demonstrated a saccular aneurysm arising from the tonsillomedullary segment of the right PICA and a second aneurysm arising from the cortical segment of the common trunk of an AICA-PICA variation. INTERVENTION: Via bilateral suboccipital craniotomy, both aneurysms were clipped. CONCLUSION: Only two cases of aneurysms arising from an AICA-PICA variation have been reported in the literature and no detailed description of the surgical anatomy of this variation has been carried out in previous publications. To our knowledge, the present report is the first description of a clinical case along with a detailed surgical anatomic study in a cadaver.