A case of a small unruptured aneurysm that enlarged, thrombosed and recanalized over a short time

Abstract

We report a case of a small aneurysm arising from the anterior communicating artery (ACOM) that rapidly enlarged with repeated thrombosis and recanalization over a short time. A 64-year-old woman presented with a minor headache. Magnetic resonance imaging (MRI) showed a 3 mm diameter aneurysm arising from the ACOM, and there was stenosis of the end of the left internal carotid artery and the moyamoya arteries in the left hemisphere. The aneurysm was not visualized by contrast-enhanced three- dimensional (3D) computed tomography angiography (CTA) after 20 days；however, conventional angiography showed the neck of the aneurysm on day 21. The disappearance and recanalization of the aneurysm neck was confirmed on repeated examination. Since there was a high risk of aneurysm rupture, microsurgical clipping of the aneurysm neck was performed on day 36. Intraoperative examination of the aneurysm revealed a thin wall, with the majority of dome thrombosed. Immediate treatment should be recommended for an aneurysm that shows thrombosis, recanalization and enlargement over a short time because of a high risk of rupture. In addition, we speculate that unilateral moyamoya disease is partially associated with the occurrence and growth of the aneurysm.