- Department of Neurosurgery, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
- Department of Neurosurgery, Fukui Prefectural Hospital, Fukui, Japan
- Department of Neurosurgery, Fujita Health University School of Medicine, Nagoya, Japan
- Department of Neurosurgery, Asanogawa General Hospital, Kanazawa, Japan
- Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, Yokohama, Japan
Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, Yokohama, Japan
DOI:10.4103/2152-7806.143722Copyright: © 2014 Kinoshita M. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Kinoshita M, Kida S, Hasegawa M, Yamashita J, Nomura M. Pathological examination of a ruptured fusiform aneurysm of the middle cerebral artery. Surg Neurol Int 30-Oct-2014;5:
How to cite this URL: Kinoshita M, Kida S, Hasegawa M, Yamashita J, Nomura M. Pathological examination of a ruptured fusiform aneurysm of the middle cerebral artery. Surg Neurol Int 30-Oct-2014;5:. Available from: http://sni.wpengine.com/surgicalint_articles/pathological-examination-ruptured-fusiform-aneurysm-middle-cerebral-artery/
Background:Little is known about the pathogenesis and clinical course of fusiform compared with saccular aneurysms. The case of a ruptured fusiform aneurysm accompanied by dissection at the M2 portion of the middle cerebral artery (MCA) is reported, along with pathological findings.
Case Description:A 41-year-old female presenting with subarachnoid hemorrhage was revealed to have a ruptured fusiform aneurysm at the M2 portion of the right MCA on angiography. She was treated with superficial temporal artery-MCA anastomosis and trapping of the aneurysm. The aneurysm consisted of a whitish fusiform dilatation with a thickened wall of the MCA and two red protrusions on it. Pathological examinations revealed disruption and fragmentation of the internal elastic lamina and intimal thickening in the fusiform lesion. There were two aneurysmal protrusions on the main fusiform dilatation. In one protruded lesion, a dissection of the intima was observed.
Conclusion:We propose that a dissection and saccular aneurysm additionally developed on the wall of a preexisting segmental ectasia of the MCA in our case. In this report, we discuss the etiology of fusiform aneurysms of the MCA.
Keywords: Dissecting aneurysm, fusiform aneurysm, internal elastic lamina, intimal thickening, middle cerebral artery
Fusiform aneurysms of the middle cerebral artery (MCA) have different pathological features, hemodynamics, and natural histories than saccular aneurysms.[
A 41-year-old female suddenly developed headache and nausea. She visited a local physician, and was referred to one of our hospitals. On admission, neither consciousness disturbance nor neurological deficit was observed. Her past history included scoliosis since birth; however, other diseases such as infection or connective tissue disease were not noted. A routine blood examination was not remarkable. Further, the examination of antigens and antibodies for infectious diseases also revealed no abnormality. Computed tomography (CT) demonstrated SAH [
(a) CT showing SAH dominantly on the right side. (b) 3D-CTA showing a dilatation of M2 of the right MCA. Two small notches can be seen on the main lesion (arrows). (c) MRI 4 months before SAH showing an abnormality on the right M2 portion (arrow). (d) MRI on admission showing a dilatation of M2 (arrow)
She underwent surgery on the 45th day after onset. Right fronto-temporal craniotomy and superficial temporal artery (STA)-MCA anastomosis were performed. Then, the lesion was trapped and resected. The lesion consisted of a dilated arterial trunk with a whitish, thickened wall and two protrusions with red walls on the main lesion [
Microphotographs of samples stained with Elastica van Gieson stain (a, c, e) and immunostained with anti-α-smooth muscle actin antibody (b, d). Cross-section of large (a, b) and small (c, d) protrusions, and a dilated arterial trunk between the two protrusions (e) are presented. Figures (a, c, e) demonstrating disruption of the internal elastic lamina (arrows) and intimal thickening (asterisk). The cross-section at the site of the large protrusion (b) showing that the lesion has an intimal flap (arrowheads) without the existence of smooth muscle cells positive for anti-α-smooth muscle actin. The small protrusion (d) has no intimal flap ×40
Fusiform aneurysms, including dissections in the anterior circulation, are rare compared with those in the vertebrobasilar system.[
In our case, MRI 4 months prior to the episode already showed the lesion with an irregular wall. It was reported that, if a dissecting aneurysm is suspected, serial radiological examinations should be conducted, because the radiological characteristics of lesion might change dynamically over a short period of time.[
The macroscopic features of our case were very unique. The lesion had a dilated arterial trunk and two small protrusions on it. The main lesion of the MCA trunk was whitish, and the cross-section of the sample showed a thickened wall structure and narrowed cavity. In contrast, the two protruded portions were reddish in appearance. There was no connection between the two protrusions. The size of the protrusions observed on 3D-CTA was much smaller than the total size of those observed macroscopically. These findings indicated that these two protrusions contained a thrombus.
Mizutani et al.[
The majority of disrupted internal elastic laminae may be covered with local intimal thickening and may not develop into aneurysms.[
Pathological examination revealed that our case might be a segmental ectasia of the MCA accompanied with newly developed dissecting and saccular aneurysms. Even a simple ectasia of the arterial trunk might have the potential to develop a dissecting or saccular aneurysm. Therefore, for such cases, serial radiological examinations and close observation are necessary.
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