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

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.

Clinical Importance of the Posterior Inferior Cerebellar Artery: A Review of the Literature

The posterior inferior cerebellar artery (PICA), with its unique anatomical complexity, is of great clinical importance and involved in many diseases including aneurysm, ischemic stroke, neurovascular compression syndrome (NVCS), arteriovenous malformation (AVM), and brain tumor. However, a comprehensive systematic review of the importance of the PICA is currently lacking. In this study, we perform a literature review of PICA by searching all the associated papers in the PUBMED database hoping to provide a better understanding of the artery. The PICA has tortuous and variable course and territory, divided into 5 segments. Various aneurysms involving PICA were not uncommon, of which the treatment is challenging. The PICA infarct typically manifests lateral medullary syndrome (LMS) and is more likely to cause mass effects. The PICA frequently compresses the medulla and the cranial nerves resulting in various neurovascular compression syndromes (NVCS). Arteriovenous malformation (AVM) fed by PICA are associated with aneurysm and dissection which have high risk of rupture and worse outcome. PICA injured by head trauma can cause fatal SAH. VA terminating in PICA probably cause Bow hunter's syndrome (BHS). The PICA supplies many brain tumors and can be used in intracerebellar chemotherapy. The PICA can be exposed and injured during surgeries especially in telovelar approach, and it also plays an important role in bypass surgeries, hinting the surgical importance of PICA. In conclusion, PICA is very important in clinical practice.

Clinical Importance of the Posterior Inferior Cerebellar Artery: A Review of the Literature

The posterior inferior cerebellar artery (PICA), with its unique anatomical complexity, is of great clinical importance and involved in many diseases including aneurysm, ischemic stroke, neurovascular compression syndrome (NVCS), arteriovenous malformation (AVM), and brain tumor. However, a comprehensive systematic review of the importance of the PICA is currently lacking. In this study, we perform a literature review of PICA by searching all the associated papers in the PUBMED database hoping to provide a better understanding of the artery. The PICA has tortuous and variable course and territory, divided into 5 segments. Various aneurysms involving PICA were not uncommon, of which the treatment is challenging. The PICA infarct typically manifests lateral medullary syndrome (LMS) and is more likely to cause mass effects. The PICA frequently compresses the medulla and the cranial nerves resulting in various neurovascular compression syndromes (NVCS). Arteriovenous malformation (AVM) fed by PICA are associated with aneurysm and dissection which have high risk of rupture and worse outcome. PICA injured by head trauma can cause fatal SAH. VA terminating in PICA probably cause Bow hunter's syndrome (BHS). The PICA supplies many brain tumors and can be used in intracerebellar chemotherapy. The PICA can be exposed and injured during surgeries especially in telovelar approach, and it also plays an important role in bypass surgeries, hinting the surgical importance of PICA. In conclusion, PICA is very important in clinical practice.

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.

Thrombosed large middle cerebral artery aneurysm mimicking an intra-axial brain tumor: case report and review of literature

This case report presents a fully thrombosed large aneurysm of middle cerebral artery mimicking an intra-axial brain tumor in a 54-year-old male patient. A small mass like lesion was found incidentally in right frontal area. Brain magnetic resonance image showed dark signal intensity on T2-weighted images and peripheral high signal intensity on T1-weighted images with peripheral rim enhancement. We considered intra-axial tumors such as glioma or metastatic tumor as a differential diagnosis. The lesion was approached transcortically, and intraoperatively, the lesion was found to be a large thrombosed aneurysm originating from the lateral lenticulostriate artery of right middle cerebral artery. One vascular clip was applied at the parent artery, and the thrombosed aneurysm was totally removed. There have been many reports of other intracranial lesions wrongly diagnosed as intracranial neoplasms. And thrombosed aneurysms mimicking intracranial neoplasm have been reported in 4 cases previously. According to those case reports, there were no efficient imaging tools to differentiate between these thrombosed aneurysms and intracranial neoplasms. We reviewed those reports and considered about the efficient method to diagnosed accurately before surgery. To sum up, when a patient presents with an intracranial lesion lying on the course of major or distal cerebral arteries, the surgeon should have thrombosed aneurysm in mind as one of the differential diagnosis and be prepared when surgically treating such lesions.

Spontaneous thrombosis in giant aneurysm of the anterior communicating artery complex in pediatric age: five-year follow-up

Intracranial aneurysms are rare in the pediatric population, especially in infancy, representing less than 1% of all aneurysms. In this age group, they are more frequent at the carotid bifurcation and in the posterior circulation, with a greater number of giant aneurysms and spontaneous aneurysm thrombosis when compared with the adults. They are life-threatening, and, therefore, early investigation, characterization of the lesion, and treatment are essential. The appropriate management depends on the child's condition, aneurysm characteristics, and the experience of a multidisciplinary team. Noninvasive and radiation-free imagiological studies play an important role in the diagnosis and follow-up of these young patients. We present the case of a 3-month-old boy with an intracranial hemorrhage secondary to the rupture of a giant aneurysm of the anterior communicating artery complex, with spontaneous thrombosis, which is a rare situation due to its location. A conservative approach was assumed and noninvasive evolutive imagiological studies revealed a reduction in the thrombosed aneurysm size and no signs of recanalization. The child recovered to his baseline neurological condition and has had no rehemorrhage until 5 years of follow-up.