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Updated: Feb 16, 2026
A Murine Model of Carotid Aneurysm Formation
Published on: September 9, 2025
Evolution into moyamoya disease in an infant with internal carotid artery aneurysms
Ryosuke Tanaka1, Satoru Takahashi1, Satomi Okano1
1Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan.
Introduction:
Moyamoya disease (MMD) is characterized by progressive stenosis and occlusion in the terminal portion of both internal carotid arteries (ICAs) and the formation of an abnormal vascular network. Because of the fragile structure of the collateral vessels, MMD is frequently accompanied by intracranial aneurysms that are mainly located within the abnormal basal network or the circle of Willis. However, the association between MMD and aneurysms of the ICAs has never been reported previously.
Case Report:
A 1-month-old infant presented with a decreased level of consciousness and arterial infarction in the right frontal and temporal lobes. Brain computed tomography angiography results showed aneurysms in both ICAs and occlusions of the distal part of the aneurysms without moyamoya collateral vessels. Aspirin therapy was initiated, and his clinical status stabilized. At 12 months of age, collateral networks of small vessels were found in the distal part of both ICAs, and MMD had evolved. At 24 months of age, he remains on aspirin therapy, and no further ischemic events have occurred.
Conclusions:
This is the first report of MMD in which ICA aneurysms and occlusions developed bilaterally in early infancy without moyamoya collateral vessels. Our case indicates that angiogenesis at the base of the brain may occur following extracellular matrix remodeling at the terminal portion of the ICAs.
Insights
This case report details the first instance of Moyamoya disease (MMD) with bilateral internal carotid artery (ICA) aneurysms and occlusions in infancy. The findings suggest a link between ICA remodeling and brain angiogenesis in early MMD development.
Area of Science:
- Neurology
- Vascular Biology
- Pediatric Neurology
Background:
- Moyamoya disease (MMD) involves progressive stenosis of internal carotid arteries (ICAs) and abnormal collateral vessel formation.
- MMD is often associated with intracranial aneurysms, typically in the circle of Willis or basal network.
- Aneurysms directly involving the ICAs in MMD have not been previously reported.
Observation:
- A 1-month-old infant presented with stroke and bilateral ICA aneurysms with occlusions, but initially lacked moyamoya collateral vessels.
- Aspirin therapy stabilized the infant's condition, preventing further ischemic events.
- By 12 months of age, collateral vessel networks characteristic of MMD had developed.
Findings:
- This is the first reported case of MMD presenting with bilateral ICA aneurysms and occlusions in early infancy.
- The initial absence of moyamoya collateral vessels highlights a distinct early disease manifestation.
- The development of MMD suggests a potential sequence involving ICA remodeling and subsequent angiogenesis.
Implications:
- This case expands the understanding of MMD's initial presentation and potential vascular pathologies.
- It suggests that extracellular matrix remodeling in the ICAs may precede or trigger the development of moyamoya vessels.
- Further research into the early pathogenesis of MMD, particularly the role of ICA aneurysms, is warranted.
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