Multiple intracranial aneurysms of inflammatory origin with subarachnoid hemorrhage.

A 46-year-old Japanese woman with a long-standing history of bronchial asthma died of subarachnoid hemorrhage with intraventricular spread, during medication by a large dose of corticosteroids. On postmortem examination, eighteen isolated arterial aneurysms were found around the circle of Willis, one aneurysm of the right middle cerebral artery being ruptured. Most of the aneurysms were fusiform or cylindrical in shape, with circumferential dilatation of the arteries. A tendency for peripheral involvement was noted in the distribution of the aneurysms. Histological examination revealed various degrees and stages of inflammatory degradation of the walls of the aneurysms. An inflammatory origin of these aneurysms seemed highly likely.