Cerebellar Syndrome Revealing a Giant Postero Inferior Cerebellar Artery Aneurysm: A Case Report and a Review of Literature

Context: Cerebellar syndrome caused by disturbances of balance and coordination is not an uncommon neurological disorder. It has varied etiologies usually caused by tumor processes or suppurative collections. Vascular causes remain very rare, especially when it is a giant aneurysm of PICA representing 1% of intracranial aneurysms. Treating giant PICA aneurysms is a very difficult task for neurosurgeons because the surgical dissection can lead to severe damage due to the intimate relationship of PICA with the brainstem or nerve structures. We report a case of giant PICA aneurysm responsible for cerebellar syndrome successfully treated with surgery. The objective of this work is to draw the attention of practitioners to this unusual cause which can lead to diagnosis wandering and a lack of planning at the time of management. Case report: A 65 years old hypertensive patient was seen for a progressive disturbance of balance and walking disorder, but worsened in the last three months with no notion of fever. On admission, the patient was lucid, oriented in time and space and presented with static and kinetic cerebellar syndrome. Brain CT-scan without and with contrast revealed a tissular mass in the posterior fossa suggesting a tumor process, however, CT angiography showed a giant aneurysm of the PICA after reconstruction. A careful microdissection by a sub-occipital approach was decided. Opening the large cistern made it possible to visualize the aneurysm sack surrounded by a yellowish gliosis. The reclining and microdissection revealed the neck of the aneurysm, which was clipped to exclude the giant aneurysm in block. Postoperative follow-up was simple with progressive improvement in the cerebellar syndrome and walking over three months. Conclusion: Giant aneurysm of the PICA is rare. The localization in the posterior cerebral fossa can be confusing. Microsurgery gives a good result.