Giant peripheral aneurysm of the posterior inferior cerebellar artery treated with excision and end-to-end anastomosis.

A patient with a giant aneurysm arising from the tonsillomedullary segment of the posterior inferior cerebellar artery (PICA) presented with clinical and computed tomography findings suggestive of spontaneous cerebellar hemorrhage. Magnetic resonance imaging led to arteriography and the correct diagnosis. Lack of a clippable neck on the aneurysm and its location proximal to the choroidal point prompted treatment by excision of the aneurysm and end-to-end anastomosis of the PICA. No neurological deficit resulted from the procedure.