A ruptured intracranial aneurysm with underlying cervicocranial fibromuscular dysplasia

Abstract

A 66-year-old woman experienced sudden headache and loss of consciousness for about 10 minutes. After regaining consciousness, she complained of severe pain in her neck and head. On physical examination, she had a stiff neck and bilateral Babinski’s sign. An axial unenhanced computed tomography (CT) scan (Panel A-1) showed extensive subarachnoid hemorrhage, including blood in the basal cisterns and fourth ventricle (arrows). Intraventricular hemorrhage is a classic presentation of the rupture of an anterior communicating artery aneurysm. A maximum intensity projection axial CT angiographic image (Panel A-2) indeed showed an aneurysm of the anterior communicating artery (arrowhead), with a maximum diameter of approximately 4 mm. Interestingly, sagittal (Panel B-1) and coronal (Panel B-2) slab maximum intensity projection CT angiographic images showed that the right extracranial internal carotid artery had a typical ‘string-of-beads’ appearance at the level of the second and third cervical vertebrae (arrows), which is pathognomonic of fibromuscular dysplasia (FMD) of the medial type.1,2 A magnified three-dimensional reconstructed CT angiographic image of the right extracranial internal carotid artery (Panel B-3) confirmed these findings. FMD is a segmental, non-atherosclerotic, noninflammatory disease of unknown cause, and most commonly affects the renal and cervicocranial arteries. It is most often encountered in the fifth decade of life and occurs predominantly in women.1,2 Cervicocranial FMD is often asymptomatic and an incidental finding on imaging or at autopsy.1,2 The condition is also associated with arterial dissection, arteriovenous fistulas, and, importantly, intracranial aneurysms.1,2 Compared to adults without any risk factors in whom intracranial aneurysms are found in Images in vascular medicine