PICA flow-related aneurysms and posterior fossa AVM: rare association and challenging management: case presentation and review of literature

The association of an infratentorial arteriovenous malformations (AVMs) with a PICA aneurysm is very rare and the presence of associated aneurysms was an independent predictive factor of poor outcome at follow-up for posterior fossa AVMs (pfAVMs). We report the case of a 57-year-old female patient admitted to our institution with a challenging management of a pfAVM associated with multiple flow-related aneurysms of the PICA. A 57-year-old patient with no medical past history was admitted to our emergency department with a sudden onset headache and severe neck stiffness. A cerebral CT Scan showed a cerebellar hematoma. Digital subtraction angiography demonstrates a right paramedian supero-posterior infratentorial AVM located at the posterosuperior part of the right cerebellar hemisphere with a small compact nidus supplied by branches of the right PICA and the right superior cerebellar artery. Venous drainage being toward the torcular. The AVM is associated with 3 flow-related aneurysms. We opted for surgical treatment of the 2 high-flow aneurysms on the distal branch of the right PICA. Patient was then sent for radiosurgery for the AVM. We opted for observation of the left small aneurysm. Microsurgery for PICA aneurysms is particularly well suited because exposure through a far-lateral craniotomy is excellent. Endovascular embolization can be used to occlude the aneurysm as well as treat the AVM at the same time in certain circumstances. Clipping or coiling the aneurysm should be discussed in a multidisciplinary meeting.