Giant aneurysm of the distal portion of the posterior inferior cerebellar artery.

The authors report a case of a giant aneurysm of the distal portion of the posterior inferior cerebellar artery presenting the classical picture of a tumor of the posterior fossa. CT scan of a giant aneurysm reveals the clear margin and high density area of aneurysm wall, and the homogeneous and high density area of the organized thrombus in a cavity of the aneurysm.