Pseudoaneurysm Formation at the Rupture Site of a Middle Cerebral Artery Aneurysm -Case Report-

Abstract

A 42-year-old man suffered subarachnoid hemorrhage manifesting as sudden severe headache one month before admission. On admission, his headache had subsided and he had no neurological deficits. Cerebral angiography demonstrated an aneurysm originating from the bifurcation of the right middle cerebral artery. The aneurysm was irregular, with a snowman-like shape. Neck clipping of the aneurysm was carried out through a right pterional approach. Intraoperatively, a red, pulsating sac mimicking a blood clot (the snowman's``head'') was located over the yellowish, thick-walled portion of the aneurysm. Exploration around the aneurysm detached the red sac from the thick-walled portion of the aneurysm. There was a small tear in the apex of the thick-walled aneurysm sac. A Sugita clip was applied to the neck of the true aneurysm. The postoperative course was uneventful and he was discharged one month later without neurological deficits. Histological examination of the red-colored sac showed the features of pseudoaneurysm. The red sac may have been a pseudoaneurysm covering the rupture site of the true aneurysm.

“Real time” Angiographic Evidence of “Pseudoaneurysm” Formation After Aneurysm Rebleeding

“…At the time of surgery for ruptured intracranial aneurysms, it is common to find a partially or completely thrombosed outpouching of the aneurysm sac corresponding to the site of rupture covered with a fresh clot. Pseudoaneurysms may occur at the rupture site of true aneurysms as consequence of aneurysm's wall tear and reorganization of the clot present on the rupture site [1]. Characteristically, true aneurysms associated to pseudoaneurysm formation may appear irregularly shaped, as in our case, suggesting the presence of a thrombus in the site of rupture [2,3].…”

Acute phase endovascular intervention on a pseudoaneurysm formed due to rupture of an anterior communicating artery aneurysm

“…Intracranial pseudoaneurysm formation due to a ruptured non-traumatic saccular aneurysm is an extremely rare condition,1–3 with characteristic angiographic findings referred to as ‘ghost aneurysm’ or ‘snowman’s head’ 1 2. At present, no detailed information about the treatment of this condition is available.…”

“…At present, no detailed information about the treatment of this condition is available. Clipping was reported to be effective and better for removing massive hematomas than endovascular coil embolization 1 2. On the other hand, endovascular coil embolization in the acute phase carries a high risk of repeated aneurysm rupture due to the fragile pseudoaneurysmal blood clot 3…”

Provocative tests and parent artery occlusion in the endovascular treatment of distal middle cerebral artery pseudoaneurysms

“…1,2 In this series, there were some angiographic clues to foresee or atleast suspect the existence of PA of the dMCA. Once the diagnosis of intracranial PA is confirmed, definitive treatment should be performed.…”

“…1,2 To provide information for clinical diagnosis and therapy of this disease, we analysed 13 patients with PA of the dMCA who underwent endovascular treatment.…”