Rupture of De Novo Middle Cerebral Artery Aneurysm 8 Years After the Clipping of Ruptured M1 Middle Cerebral Artery Aneurysm

Abstract

BACKGROUND Development and rupture of a de novo intracranial aneurysm is rare. Little is known regarding its etiology and the appropriate timing of follow-up angiograms after surgical clipping or coiling. CASE REPORT We present a case report of a 39-year-old male smoker with history of hypertension who developed a de novo aneurysm 8 years after surgical clipping of an aneurysm in the middle cerebral artery in the same segment. He presented with neck rigidity and drowsiness. Laboratory analysis did not show blood dyscrasia. Brain computerized tomography showed right temporal lobe hematoma and 4-vessel angiogram demonstrated de novo aneurysm in the same segment of the M1 middle cerebral artery, which was confirmed by intraoperative microsurgical findings. We review the literature on such cases and discuss the pathophysiology, diagnosis, and treatment of this condition. De novo aneurysm, although rare, can develop within days to as long as 10 years after surgical clipping or coiling. CONCLUSIONS This rare case of de novo aneurysm supports follow-up imaging of patients after initial surgical clipping for up to 10 years.

Figure 1.

(A, B) Preoperative angiogram after contrast injection of the right carotid artery, confirming the presence of a sacular aneurysm of the middle cerebral artery in segment M1. (C, D) Preoperative computed tomography angiogram confirming the presence of a right sacular aneurysm of the middle cerebral artery segment M1.

Figure 2.

(A–D) Postoperative angiogram of the right internal carotid artery 1 week after surgical clipping. A clip was placed on the previous M1 right middle cerebral artery aneurysm (white arrows).

Figure 3.

(A–D) Brain computed tomography with contrast 8 years after surgery showing a right temporal lobe hematoma, extending from the Sylvian fissure medially, posteriorly, and superiorly with a mild mass effect. (E, F) Selected angio-gram of the right internal carotid artery showing a multilobulated brain aneurysm in the M1 segment at the side opposite the previous clip. (G, H) Follow-up angiogram 1 week after microsurgical clipping; no residual brain aneurysms were observed.

Figure 4.

Intraoperative microsurgical view of the second surgery (A) showing an atheroma in middle cerebral artery close to the neck of the aneurysm, neck of the de novo aneurysm (NA); (B) showing the atheroma and lobulated sac of the aneurysm. (C) Old aneurismal clip (OC), new aneurismal clip (NC), atheroma (A), sacular aneurysm after clipping (SA). (D) Aneurysm sac (CS) cauterized after clipping and the cavity (C) of the temporal lobe hematoma after evacuation.