[Case of giant aneurysm of the basilar artery]

The authors report a case of a giant aneurysm of the basilar artery of the brain diagnosed accidentally on autopsy. Slowly progressive syndrome of bulbar involvement began after craniocerebral trauma. Of considerable interest was the misleading result of pneumoencephalography which showed a normal pattern of basal cisterns. In the light of results of positive-contrast ventriculography an inoperable expanding lesion of the anterior part of the brain stem with associated hydrocephalus was diagnosed and symptomatic treatment was started inserting a Pudenz-Heyer valve. Despite normalization of intracranial pressure the patient died. Vertebral angiography would not have permitted the aneurysm to be diagnosed intravitally since its lumen was filled with clots.