Intracavernous de Novo Aneurysms without Prior Manipulation of the Harboring Vessel: Report of Two Cases

Intracavernous aneurysms of the cranial base, though less frequent than intradural intracranial aneurysms, can pose considerable therapeutic problems. To date, little is known concerning their spontaneous development and eventual growth kinetics. We report the observation of two de novo aneurysms without prior therapeutic manipulation of the vessels. In our first case, the 33-year-old woman had suffered from an intracerebral hemorrhage at the age of 22. At this time, neurosurgical evacuation was performed, neither angiographically nor histologically was an underlying vascular malformation disclosed. During follow-up observation 11 years later, a cavernous aneurysm of the right internal carotid artery was detected, together with an arteriovenous malformation of the left pericallosal artery next to the former hemorrhage. In the second case, the 49-year-old woman had undergone magnetic resonance imaging (MRI) for headache, revealing two intracavernous aneurysms of the right internal carotid artery. During follow-up, 7 years later, angiography disclosed a de-novo aneurysm of the left internal carotid artery, and an enlargement of the more distal right-sided aneurysm. Most cases of de novo aneurysm formation are described intradurally and after manipulation of the harboring vessel. In the patients presented here, therapeutically induced hemodynamic changes or vessel wall manipulations are not involved, pointing to a cerebrovascular predilection, that—in combination with a set of risk factors—leads to the development of cavernous aneurysms.