Basal rupture of saccular aneurysm. A pathological case report.

In a case of subarachnoid hemorrhage, the arteries of the circle of Willis were left undisturbed and undissected at postmortem examination. A block of frontal lobe tissue with the attached vessels was serially sectioned disclosing in its entirety a saccular aneurysm that had ruptured at the base rather than the dome. The histology of the hemostatic process was clearly depicted.