Obstructive hydrocephalus due to a giant aneurysm of the internal carotid bifurcation.

A rare case of obstructive hydrocephalus associated with a giant aneurysm of the internal carotid artery is presented. The giant aneurysm, which was located in the prepontine cistern, was initially thought to be of basilar artery origin. Cerebral computed angiotomography had the most diagnostic value in disclosing the partially thrombosed giant aneurysm and its relationship with the surrounding arteries. After undergoing a ventriculoperitoneal shunt operation, the patient's clinical symptoms markedly improved.