Spontaneous thrombosis of giant intracranial aneurysm and posterior cerebral artery followed by also spontaneous recanalization

Spontaneous thrombosis of a large unruptured intracranial aneurysm causing ischemic stroke due to occlusion of the parent artery: A case report and literature review

Spontaneous thrombosis of an unruptured large or giant saccular intracranial aneurysm is a well-known phenomenon and can cause ischemic stroke (IS), which is a rare event. The possible pathogenic mechanisms of IS include distal embolic occlusion secondary to migration of the intra-aneurysmal thrombus, occlusion of the parent artery lumen caused by the retrograde extension of the aneurysmal thrombosis, external compression of the parent artery due to the increased aneurysmal mass effect. Among these, IS due to simultaneous thromboses of the aneurysm and its parent artery is extremely rare, with only a few cases reported in the literature. Herein, we present a case of a 18-year-old woman who suffered an acute IS, attribute to spontaneous complete thrombosis of an unruptured large saccular aneurysm of the right middle cerebral artery with occlusion of the parent artery, and we review the literature simultaneously.

Parent Artery Chronical Occlusion after Endovascular Treatment of a Unruptured "True" Posterior Communicating Artery Aneurysm

A case of a patient with a true large unruptured posterior communicating artery (PCoA) aneurysm in a distal segment of PCoA, who was treated by interventional therapy via an ipsilateral occlusion of the internal carotid artery (ICA), is reported. Although the treatment went very well and the patient recovered very well, angiography 6 months after the operation showed that left PCoA had occluded and the aneurysm disappeared. The temporary recanalization of occluded ophthalmic segment of ICA can be a pathway for interventional therapy. Mechanism and preventive measures for spontaneous occlusion of the PCoA harboring an aneurysm still needs further study.

Spontaneous Thrombosis of a Giant Cavernous Internal Carotid Artery Aneurysm and Parent Vessel Occlusion in a Patient With Bilateral Cavernous Internal Carotid Artery Aneurysms

Spontaneous thrombosis of giant aneurysms is a well-reported phenomenon. However, reports of complete occlusion of the aneurysm and parent vessel are scarce. Here, we describe the case of a patient with spontaneous thrombosis of a giant cavernous internal carotid artery (ICA) aneurysm and occlusion of the ICA. A 59-year-old female initially presented with frequent headaches and was otherwise completely neurologically intact. Magnetic resonance angiography (MRA) demonstrated a giant, partially thrombosed right cavernous ICA aneurysm. She was also found to have a contralateral left-sided intracavernous aneurysm. Cerebral angiogram revealed a giant, partially thrombosed right cavernous segment ICA aneurysm measuring 27.1 x 32.4 mm with slow, turbulent flow within the lesion. The patient was started on aspirin 325 mg and a dexamethasone taper with plans for follow-up flow diversion for treatment of the right cavernous ICA aneurysm. The patient presented three months later with worsening headaches, and on examination was found to have anisocoria (right > left) with a nonreactive right pupil as well as cranial nerve III/IV palsies, and facial edema. There was no evidence of intracranial hemorrhage or ischemia seen on head computed tomography (HCT). The diagnostic cerebral angiogram demonstrated complete occlusion of the right ICA at the carotid bifurcation with no filling of the giant right cavernous ICA aneurysm and a stable left cavernous ICA aneurysm. Although the exact mechanism of simultaneous thrombosis of the aneurysm and its parent artery remains unclear, it is likely due to stagnant flow. The presence of cranial nerve palsies was most likely secondary to acute edema of the lesion after thrombus formation. There was no evidence of ischemic symptoms due to collateral flow across a patent anterior communicating artery.

Spontaneous thrombosis of a giant cavernous-carotid aneurysm with simultaneous ipsilateral complete parent artery occlusion: a rare phenomenon and review of the literature

Cavernous-carotid artery (CCA) aneurysms represent about 3-5% of all intracranial aneurysms. Spontaneous thrombosis of a CCA aneurysm with simultaneous occlusion of its parent vessel is an extremely rare phenomenon with few reported cases in the literature offering different management strategies. A 54-year-old Asian female presented with a one day-history of painless left eye conjunctival injection, proptosis, and features of cavernous sinus syndrome (cranial nerve III, IV, V1, V2, and VI palsies). Imaging revealed a giant thrombosed CCA aneurysm measuring 3.6cmx3.4cm with complete thrombosis of the left cervical internal carotid artery (ICA) and adequate collaterals from the anterior and posterior communicating artery and branches of the left external carotid artery. Management was conservative with antiplatelet therapy and close clinical-radiological follow-ups. The outcome was satisfactory. Data in the literature on this condition is limited due to its exceedingly rare occurrence. The majority of patients do well via a conservative approach and surgery is rarely indicated. For clinically stable patients, especially those with adequate collateral circulation and tolerance to Balloon Test Occlusion, we advocate for a conservative approach and initiation of anti-platelet therapy to treat these patients. Emphasis is needed on close serial clinical-radiological surveillance in these cases to monitor the propagation of the thrombus as well as the development of new and/or enlarging pre-existing aneurysms in the contralateral ICA circulation.

A complete thrombotic large aneurysm at the nonbranching segment of the distal anterior cerebral artery mimicking a cavernous malformation: illustrative case

BACKGROUND

Thrombotic aneurysms at the nonbranching segment of the distal anterior cerebral artery (ACA) are extremely rare and difficult to differentiate from cavernous malformations by radiographic features alone.

OBSERVATIONS

Computed tomography and magnetic resonance imaging of a 30-year-old female patient with a chronic headache complaint revealed a 22-mm frontal lobe mass. The mass showed heterogeneous mixed intensity and hemosiderin deposits on magnetic resonance images. It was not visualized by conventional angiography, indicating that the mass and ACA/other vessels were not connected. The patient was preoperatively diagnosed with a cavernous malformation. However, during resection, the mass surface was white and smooth, different from a cavernous malformation. Although the mass was adherent to the pericallosal artery branch, no luminal continuity was observed. After detachment, the mass was completely resected. Pathological and immunohistochemical findings indicated a vessel wall and interior thrombus. The patient was rediagnosed with a thrombotic aneurysm at the distal ACA nonbranching segment and discharged 10 days postsurgery without neurological deficits.

LESSONS

Because radiographic findings of thrombotic aneurysm and cavernous malformation are similar, mass lesions in contact with major arteries should be differentiated as thrombotic aneurysms, even when the artery lumen appears disconnected from the mass.

Intracranial Aneurysm in Pediatric Population: A Single-Center Experience

PURPOSE

Pediatric intracranial aneurysms (PIA) are rarer and more complex when compared to adult aneurysms. In general, the clinical presentation of PIA is due to a mass effect, but the presenting symptoms can be also related to ischemia, subarachnoid hemorrhage (SAH), or in a combination of different symptoms. This paper aimed to report a single-center experience with clinical and angiographic aspects of brain aneurysm in children.

METHODS

We retrospectively reviewed our prospectively maintained database for patients with intracranial aneurysms in our institution from July 2015 to February 2021. Among these, all patients under 18 years of age submitted to a diagnostic or therapeutic procedure for an intracranial aneurysm were included.

RESULTS

Twelve patients were submitted to diagnostic or therapeutic procedures in our department. Three of them had multiple aneurysms, and in total, 17 intracranial aneurysms were assessed in this study. The most frequent location was in the middle cerebral artery (7 cases/41%). Five out of twelve children (42%) presented SAH due to ruptured aneurysm. Three patients (25%) had symptoms due to the mass effect from large aneurysms, with compression of cranial nerves or brainstem. Aneurysms diameters ranged from 1.5 mm to 34 mm (mean 14.2 mm), with six aneurysms being giant and eight being nonsaccular/fusiform. Twelve aneurysms were submitted to endovascular treatment, with one treatment-related clinical complication and later death.

CONCLUSION

PIAs are rare diseases that can arise from a variety of different underlying pathological mechanisms. The management of these conditions requires a detailed understanding of the pathology and a multidisciplinary approach. Despite the availability of new technologies, parent vessel occlusion remains a valid option for aneurysms in the pediatric population.

Thrombotic Aneurysm of Posterior Inferior Cerebellar Artery

BACKGROUND

Spontaneous thrombosis of an intracranial aneurysm is rare but is common in fusiform or large cystic aneurysms, which result in subarachnoid hemorrhage after rupture. This case reports a 47-year-old woman with subarachnoid hemorrhage who developed spontaneous thrombosis of an aneurysm due to rupture of the posterior inferior cerebellar aneurysm.

CASE DESCRIPTION

The patient was admitted to the hospital with history of sudden headache and vomiting for 3 days. According to early imaging findings, she was initially diagnosed as having a cavernous hemangioma with hemorrhage in the left cerebellum, but according to the intraoperative pictures and postoperative pathologic results, the diagnosis was an aneurysm with thrombosis.

CONCLUSIONS

This case represents a rare but important complication of ruptured intracranial aneurysm, which can be easily misdiagnosed or ignored. It should be given great attention and considered in patients with subarachnoid hemorrhage who are negative for imaging examinations.

Completely Thrombosed Giant Intracranial Aneurysm with Spontaneous Thrombosis of the Parent Artery: Is It Nature's Divine Intervention and a Self-Cure?

BACKGROUND

Although partial thrombosis is common with intracranial aneurysms, complete aneurysmal thrombosis is extremely rare. An even rarer and seldom reported phenomenon is the spontaneous complete occlusion of the parent artery in the presence of a thrombosed aneurysm. Given the unclear natural history of this phenomenon, therapeutic decision making may be rather difficult. Here we report a case of right cavernous carotid artery aneurysm with spontaneous right internal carotid artery (ICA) thrombosis in a 45-year-old man.

CASE DESCRIPTION

Our patient presented almost 1 month after an episode of sudden-onset severe holocranial headache associated with vomiting that had resolved completely within 2 days. He was neurologically intact at the time of presentation. A computed tomography (CT) scan done at the time of ictus showed a rounded hyperdensity with the epicenter at the right parasellar region along with nonvisualization of the ipsilateral ICA on CT angiography. Magnetic resonance imaging (MRI) suggested a diagnosis of a completely thrombosed right cavernous segment ICA aneurysm. Intra-arterial angiography confirmed a complete ipsilateral ICA thrombosis and a good arterial cross-flow from the left side to the bilateral anterior and middle cerebral artery territories. We started the patient on oral aspirin and a close clinicoradiologic follow-up after having decided against any active intervention.

CONCLUSIONS

Spontaneous thrombosis of an intracranial aneurysm and the parent artery is rare, with only a few cases reported in the literature. In the absence of symptoms and adequate collateral circulation, these patients are perhaps best managed conservatively.