An Unusual Case of a Thrombosed Giant Distal PICA Aneurysm Simulating a Large Cavernous Angioma

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.

Giant aneurysms of the distal posterior inferior cerebellar artery - systematic review

BACKGROUND

Posterior inferior cerebellar artery (PICA) aneurysms are uncommon and are typically found at the origin or proximal segments of the vessel. Giant aneurysms are uncommon and present unique treatment challenges. Giant distal PICA aneurysms are exceedingly rare and have traditionally been managed via open surgical approaches.

METHODS

A total of 207 studies were assessed, identifying 26 cases of giant distal PICA aneurysms from 26 separate publications. One additional case is described followed by a review of presentation, anatomical characteristics, treatment and outcome.

RESULTS

Presentation was due to local mass effect in 19 (70%), hydrocephalus in 4 (15%) and acute haemorrhage in 5 (19%). All reported cases were partially (86%) or completely (14%) thrombosed. The telovelotonsillar segment was involved in 18/24 (75%) cases. Two cases (7%) were associated with an arteriovenous malformation. Twenty-two (81%) were managed surgically and 5 (19%) managed endovascularly. Outcome was good in 22 (85%) and poor in one (4%).

CONCLUSIONS

Giant distal PICA aneurysms can be managed effectively through a variety of open surgical and endovascular techniques.

A pediatric case of completely thrombosed giant cavernous carotid aneurysm with ipsilateral ICA occlusion mimicking an intra-axial cystic lesion: a case report and review of the literature

INTRODUCTION

There have been a few cases where completely thrombosed cavernous carotid artery (CCA) aneurysms have resembled neoplasms based on neuroimaging data, but no reports have been documented in children.

CASE REPORT

We describe an unusual pediatric case of a huge cavernous sinus mass mimicking a cystic neoplasm with peripheral rim enhancement on magnetic resonance imaging (MRI), where the surgery and subsequent histopathological investigation revealed that this mass was a completely thrombosed giant aneurysm of the CCA. The patient showed postoperatively no new neurological deficits and discharged a week later after surgery.

CONCLUSIONS

In this case report, we describe a pediatric case of a completely thrombosed giant CCA aneurysm with ipsilateral internal carotid artery (ICA) occlusion, which imitates an intra-axial cystic lesion on MRI.

Giant Posterior Inferior Cerebellar Artery Aneurysm Mimicking a Brainstem Tumor

Aneurysms from the vertebrobasilar system are rare, accounting for only 5%-10% of all intracranial aneurysms. The most common sites in which these lesions occur are the bifurcation of the basilar artery and the origin of the posterior inferior cerebellar artery (PICA). When the aneurysms present in the distal portion of the PICA, they represent from 0.5% to 6%. These aneurysms are called giant when they exceed 25 mm in diameter. We present a case of a 49-year-old male who presented with acute obstructive hydrocephalus, which required ventriculoperitoneal shunting and left hemispheric cerebellar syndrome. The magnetic resonance imaging study revealed an occupative mass located in the fourth ventricle, and diagnostic angiography showed a partially thrombosed giant saccular aneurysm in the posterior inferior cerebellar artery. He underwent surgical management via a lateral suboccipital approach. The aneurysm was remodeled and clipped successfully without complications, with an uneventful postoperative course.

Although rare, PICA aneurysms should always be considered when posterior fossa syndrome occurs, including brainstem and cranial nerve compression symptoms. It can easily be misdiagnosed as a neoplastic lesion, especially when the aneurysm reaches big or giant size. Therefore, complete diagnostic studies, such as cerebral angiography, must be performed. Surgical clipping must be offered as the first line of treatment. It provides occlusion of the aneurysm and relieves compressive symptoms.

Ring enhanced aneurysm due to vasa vasorum of aneurysm wall mimicking a metastatic brain tumor

Background

A spherical intracranial mass can be occasionally misdiagnosed due to the lack of typical radiographic features. Completely thrombosed intracranial aneurysms (CTIA) are uncommon, but a possible differential diagnosis must be considered to guarantee the best surgical approach for these lesions.

Case Description

Here, we report an extremely rare case of a right frontal mass mimicking a brain tumor, in which the surgery unveiled a CTIA of the right middle cerebral artery (MCA). A 56-year-old woman presented with right hemiparesis and mild headache. Magnetic resonance imaging (MRI) revealed a right frontal mass with peripheral edema. The lesion enhanced on initial and follow-up MRI of the brain. Subsequent vascular studies and metastatic workup were negative. A temporal craniotomy with neuronavigation (Brain Lab AG, Germany) was performed and an intraoperative diagnosis of a thrombosed aneurysm along the branch of the MCA was established. The aneurysm was successfully trapped and resected. The patient did not exhibit any postoperative neurological deficits.

Conclusion

This is the rare report of a ring enhanced completely thrombosed aneurysm due to vasa vasorum which is misdiagnosed as metastatic brain tumor. In case of an intracranial ring enhanced mass with signs of intralesional hemorrhage and peripheral edema, CTIA should be considered as a possible differential diagnosis.

Distal middle cerebral artery dissection with concurrent completely thrombosed aneurysm manifesting as cerebral ischemia. A case report and review of the literature

We report the case of a 70-year-old woman who presented with an acute ischemic stroke involving the left frontal operculum secondary to an M2 dissection and a concomitant completely thrombosed aneurysm of the left distal middle cerebral artery. Initial imaging work-up was inconclusive due to the lack of typical radiographic features and only repeated imaging studies pointed towards the presence of an arterial dissection combined with a completely thrombosed aneurysm. The aneurysm was partially clipped and wrapped with excellent clinical result at 1-year follow-up. The clinical, imaging and therapeutic challenges of this rare entity are discussed.

Completely Thrombosed Distal Middle Cerebral Artery Aneurysm Mimicking a Cavernous Angioma: Case Report and Review of the Literature

BACKGROUND

Distal middle cerebral artery (MCA) aneurysms originate from branches of MCA distal to its main bifurcation or the peripheral branches. Distal MCA aneurysms are uncommon compared with saccular aneurysms, which develop along the proximal trunks of MCA. However, thrombotic aneurysms, characterized by organized intraluminal thrombus and solid mass, are frequently in the large and giant size range, whereas complete thrombosis of non-giant MCA aneurysms is very rare.

CASE PRESENTATION

We present the clinical case of a 53 years-old woman with a completely thrombosed medium distal MCA aneurysm mimicking a cavernous angioma. She came to our emergency department after the onset of tinnitus and persistent headache. Magnetic resonance imaging performed subsequently showed a nodular mass surrounded by edema located in the temporal lobe with a homogeneous peripheral contrast enhancement. Furthermore, angiography showed regular flow in the MCA and confirmed the diagnosis of cavernous angioma. The patient underwent surgery, and the lesion was found to be a thrombosed aneurysm originating from the distal temporal branch of the left MCA (M2 segment).

CONCLUSIONS

To our knowledge, this is the first report of a thrombosed distal medium MCA aneurysm that mimicked a cavernous angioma. The completely thrombosed aneurysm can be confused with intracranial lesions or cavernous malformations, which can have similar radiographic features without angiographic anomalies, so it is mandatory to consider the possibility of a thrombosed aneurysm for a correct differential diagnosis.

A completely thrombosed, nongiant middle cerebral artery aneurysm mimicking an intra-axial neoplasm

Background:

Few reports exist regarding thrombosed aneurysms where the initial work up was concerning for a neoplasm. To date, no published reports exist regarding a nongiant thrombosed middle cerebral artery aneurysm, where the primary workup and treatment plan was directed toward a preliminary diagnosis of intra-axial neoplasm.

Case Description:

We report a 43-year-old female who presented with a generalized tonic-clonic seizure attributed to a lesion along the right superior temporal gyrus. The lesion enhanced on initial magnetic resonance imaging (MRI) of the brain, as well as on follow-up MRI. Subsequent vascular studies and metastatic work up were negative. A craniotomy with image guidance was performed and an intraoperative diagnosis was made of a thrombosed aneurysm along a branch of the middle cerebral artery. The aneurysm was trapped and resected as there was no significant flow from the branch as seen on the prior cerebral angiogram. The patient had an uneventful postoperative course.

Conclusion:

Completely thrombosed, nongiant aneurysms can mimic an intra-axial neoplasm. Typical imaging features for thrombosed aneurysms may be missed, especially if the aneurysms are small, where imaging characteristics of the intraluminal contents is more difficult to appreciate. Although imaging may be consistent with a neoplastic lesion, there should be suspicion for a potential underlying aneurysm.

Giant aneurysm of distal posterior inferior cerebellar artery: a case report and review of the literature

INTRODUCTION

Aneurysms in the vertebrobasilar system are rare and in the distal segment of the posterior inferior cerebellar artery they are even less frequent. Giant aneurysms are also rare in the posterior cranial fossa. Giant aneurysms of the distal posterior inferior cerebellar artery generally can have mainly compressive effects on the adjacent structures and they can be mistaken for tumors.

CASE PRESENTATION

We report the case of a 74-year-old Italian woman who presented with a complaint of dizziness. Her dizziness was found to be a result of aneurysmal dilatation arising from the distal segment of the right posterior inferior cerebellar artery. A mid-line suboccipital craniotomy was performed, and the aneurysm was clipped without post-operative deficits and with improvement in the patient's dizziness. In our present report, we also review the literature and discuss our case with regard to the clinical and radiological features and surgical procedure performed.

CONCLUSION

To the best of our knowledge, few cases of this type of aneurysm have been described in the literature. Our patient had a good outcome after surgical treatment.

Thrombosed large distal posterior inferior cerebellar artery aneurysm mimicking an infratentorial ependymoma

Large or giant intracranial aneurysms can simulate brain tumors clinically and radiologically by virtue of their progressive mass effect. Unlike aneurysms from alternative locations, those arising from the distal posterior inferior cerebellar artery (PICA) are uncommon. We report a patient who experienced progressive hemiparesis with magnetic resonance imaging findings suggestive of an infratentorial ependymoma. Intraoperatively, a thrombosed large aneurysm of the distal PICA was unexpectedly encountered. The aneurysm was clipped and the patient did not develop any permanent neurological deficit. This case illustrates the radiological nuances of large aneurysms and infratentorial ependymomas. Three-dimensional contrast-enhanced magnetic resonance angiography can be falsely negative and the importance of the "target" sign is emphasized. One should be cognizant of this possible diagnosis for patients with midline fourth ventricular lesions in order to reduce surgical risk.