Partially thrombosed middle cerebral artery-lenticulostriate artery aneurysm with native radiological examinations suggesting proximal lenticulostriate artery aneurysm: A case report
- Department of Neurosurgery, National Hospital Organization Beppu Medical Center, Beppu, Oita, Japan
- Department of Neurosurgery, Oita Prefectural Hospital, Oita, Japan
- Department of Neurosurgery, Nakatsu Neurosurgical Hospital, Nakatsu, Oita, Japan
- Department of Neurosurgery, Oita University Faculty of Medicine, Hasama, Oita, Japan.
Mitsuhiro Anan, M.D., Ph.D, Department of Neurosurgery, National Hospital Organization Beppu Medical Center, Beppu, Oita, Japan.
DOI:10.25259/SNI_597_2021Copyright: © 2021 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Mitsuhiro Anan1, Yasuyuki Nagai2, Takeshi Matsuda1, Kazuya Morimoto3, Minoru Fujiki4. Partially thrombosed middle cerebral artery-lenticulostriate artery aneurysm with native radiological examinations suggesting proximal lenticulostriate artery aneurysm: A case report. 03-Aug-2021;12:389
How to cite this URL: Mitsuhiro Anan1, Yasuyuki Nagai2, Takeshi Matsuda1, Kazuya Morimoto3, Minoru Fujiki4. Partially thrombosed middle cerebral artery-lenticulostriate artery aneurysm with native radiological examinations suggesting proximal lenticulostriate artery aneurysm: A case report. 03-Aug-2021;12:389. Available from: https://surgicalneurologyint.com/surgicalint-articles/11014/
Background: Preservation of the lenticulostriate artery (LSA) is crucial. LSAs usually cannot be spared with LSA aneurysms, when surgical clipping/excision or endovascular embolization of the LSA itself is performed. On the other hand, the LSA should be separated and preserved for proximal middle cerebral artery (M1)-LSA aneurysms.
Case Description: We report a case of M1-LSA aneurysm with native radiological examinations suggesting LSA aneurysm. The highlight of this unusual case was that during surgery, the aneurysm orifice was almost covered with thrombus and blood flow in an aneurysm that appeared separate from M1. Partial thrombectomy-clip reconstruction was performed, and M1 and LSAs were well preserved.
Conclusion: Even with currently developed radiological modalities, thrombosed intracranial aneurysms may be misdiagnosed, depending on intraluminal flow conditions. Intraoperative findings from craniotomy sometimes contribute to a better understanding of the pathophysiology and decisions on appropriate treatment strategy.
Keywords: Intracranial aneurysm, Lenticulostriate artery aneurysm, Middle cerebral artery aneurysm, Thrombosed intracranial aneurysm
Preservation of the lenticulostriate artery (LSA) is crucial to the treatment of intracranial lesions such as intracranial aneurysms and tumors. LSAs usually cannot be spared with LSA aneurysms, when surgical clipping/excision or endovascular embolization of the LSA itself is performed to cure LSA aneurysms.[
History and examination
A 23-year-old woman presented with a 1-day history of the right hemiparesis before admission to our clinic. She was otherwise neurologically intact with normal mental status, sensation, reflexes, and coordination. No hematological or electrolyte abnormalities, underlying pathologies such as vasculitis, or autoimmune diseases such as systemic lupus erythematosus were identified.
Initial magnetic resonance imaging (MRI) and computed tomography (CT) of the head demonstrated acute infarction of the left basal ganglia, but no subarachnoid hemorrhage [
Preoperative radiological examinations. (a) Initial axial-view diffusion-weighted magnetic resonance imaging (MRI) shows acute stroke within the territory of the lenticulostriate artery. (b and c) Initial axial-view computed tomography (CT) shows a high-density spot (b), and axial-view T1-weighted MRI shows a high-intensity spot at the base of the anterior perforated substance (c). (d and e) Initial multiplanar reconstruction MR angiography (slab: 15.0 mm thickness) (d) and CT angiography (e) on coronal view show an aneurysm separate from the proximal middle cerebral artery. (f) Digital subtraction angiography at the 2-week follow-up shows the aneurysm has grown.
The cerebral infarction of the left basal ganglia was not aggravated on repeat CT or MRI, and neurological symptoms resolved within 2 weeks. However, DSA revealed filling of 7.8 mm of the fusiform aneurysm near the left M1 segment, with the body of the aneurysm separate from M1 [
Left pterional craniotomy was performed. Intraoperatively, the orifice of the aneurysm was identified not on the proximal LSA but on M1. The aneurysm was brown in color and was diagnosed as a thrombotic aneurysm [
Intraoperative microscope views. (a-f) A left frontotemporal approach shows the thrombosed aneurysm (asterisk) and perforators (triangle) of the left proximal middle cerebral artery (M1) (a), some small lenticulostriate artery (LSAs) and arteries supplying the surrounding brain (arrows) adherent to the surface of the aneurysm (b), collapsed M1 after neck clipping with fenestrated clip without thrombectomy (c), thrombectomy of the aneurysm with trapping of M1 (d), collapsed small LSA adherent to the aneurysm (arrow) (e), and preserved M1 and LSA (triangle) flow after thrombectomy-clip reconstruction with indocyanine green videoangiography (f). Fr, frontal lobe; Tm, temporal lobe.
Postoperatively, right hemiparesis re-aggravated, and a small new infarction was detected on MRI in the basal ganglia beside the previous infarction [
Postoperative imaging. (a) Diffusion-weighted magnetic resonance imaging shows new infarction (arrow) beside the previous infarction (double arrow). (b and c) Digital subtraction angiography (DSA) and 3D-DSA (c) show no filling of the aneurysm and preservation of M1 and the perforators (triangle).
LSA aneurysms causing cerebral ischemia are exceedingly rare. Lama et al. presented 42 cases of LSA aneurysm, including one case of their own, identified in a review of the literature since 1960,[
The key strategy for LSA aneurysms and for M1-LSA aneurysms is quite different. In general, preserving the LSA is impossible because the LSA is the parent artery of the LSA aneurysm. Surgical clipping/excision of the LSA itself has been allowed and performed, and endovascular embolization of the LSA has recently been increasing.[
Lawton et al. classified their 68 thrombotic aneurysms into six types by organized intraluminal thrombus and solid mass.[
At present, although recently developed radiological modalities are often quite useful and worthwhile to diagnose conditions of thrombosed intracerebral aneurysms, craniotomy can help reveal the truth. Darkwah Oppong et al. reported a ruptured, masked aneurysm subsequent to thrombosis of the associated vessel, and intraoperative findings were useful for deciding the treatment strategy.[
Partially thrombosed aneurysm may be misdiagnosed depending on intraluminal flow conditions. This report reminds us that intraoperative exploration by craniotomy may contribute to a better understanding of the pathophysiology and selection of an appropriate treatment strategy.
1. Chaohui L, Chuan H, Hongqi Z. Embolization of ruptured distal lenticulostriate artery aneurysms. World Neurosurg. 2018. 118: e147-54
2. Darkwah Oppong M, Jabbarli R, Radbruch A, Sure U, Dammann P. Blind date with an aneurysm: Acute M1 middle cerebral artery thrombus with native computed tomography scan suggesting aneurysm rupture. World Neurosurg. 2019. 132: 103-5
3. Elsharkawy A, Lehečka M, Niemelä M, Billon-Grand R, Lehto H, Kivisaari R. A new, more accurate classification of middle cerebral artery aneurysms: Computed tomography angiographic study of 1,009 consecutive cases with 1,309 middle cerebral artery aneurysms. Neurosurgery. 2013. 73: 94-102
4. Lama S, Dolati P, Sutherland GR. Controversy in the management of lenticulostriate artery dissecting aneurysm: A case report and review of the literature. World Neurosurg. 2014. 81: 441.e1-7
5. Lawton MT, Quiñones-Hinojosa A, Chang EF, Yu T. Thrombotic intracranial aneurysms: Classification scheme and management strategies in 68 patients. Neurosurgery. 2005. 56: 441-54