Intrameatal thrombosed anterior inferior cerebellar artery aneurysm mimicking a vestibular schwannoma

Abstract

Aneurysms of the anterior inferior cerebellar artery (AICA) are a rare entity. Purely intrameatal aneurysms are even rarer. The authors report an intrameatal thrombosed AICA aneurysm mimicking a vestibular schwannoma that was treated by resection and end-to-end anastomosis. This 22-year-old man presented with acute hearing loss, vertigo, and moderate facial palsy. Magnetic resonance imaging showed an atypical intrameatal lesion with dilation of the internal auditory canal. Microsurgical inspection via a retrosigmoid approach and drilling of the posterior wall of the internal auditory canal revealed a thrombosed AICA aneurysm. The aneurysm was excised, and an end-to-end suture was performed to restore AICA continuity. Intraoperative indocyanine green videoangiography as well as postoperative digital substraction angiography showed a good revascularization. Intrameatal AICA aneurysms may present with symptoms similar to vestibular schwannomas. End-to-end reanastomosis after aneurysm resection is a treatment option when clipping is impossible.

Partially thrombosed giant aneurysm arising from a distal anterior inferior cerebellar artery–posterior inferior cerebellar artery variant: A case report

“…Most infratentorial mass lesions presenting with hearing impairment involve brain tumors, such as a vestibular schwannoma. This case highlights hearing difficulty as a manifestation of an intracranial thrombosed aneurysm at the CPA [1]. A giant thrombosed intracranial aneurysm should be considered in the differential diagnoses of CPA lesions.…”

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

“…Magnetic Resonance may demonstrate a lumen with heterogeneous signal on T1- and T2-weighted images, “onion skin” appearance on noncontrast T1 weighted images, a flow void sign, thrombus non-enhancement or rim enhancement along the thrombus margin [12 , 13] . Eleven similar cases have been reported in the literature ( Table 1 ) and were commonly mistaken for neoplasms on initial imaging work up with the final diagnosis commonly established during surgery [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] . Only 3 aneurysms affected the middle cerebral artery.…”

Thrombosed Large Middle Cerebral Artery Aneurysm Mimicking an Intra-Axial Brain Tumor: Case Report and Review of Literature

“…It is the result of hematogenous spread from a primary focus in the lung [ 12 ]. In clinical field, it is not so rare to misdiagnosed thrombosed aneurysm as a brain tumor, however, thrombosed aneurysms mimicking intracranial neoplasm have been reported only in 4 cases previously ( Table 1 ) [ 13 , 14 , 15 , 16 ]. It might be because it seems not so valuable to report.…”

“…But, in this case, it seemed valuable to share, because as mentioned above, it was not so big as giant aneurysms and the location of aneurysm was lenticulostriate artery which is rare. Among the other reported cases, the aneurysms of 2 cases [ 13 , 16 ] were included in a category of giant aneurysm and the aneurysms of 3 cases [ 13 , 14 , 16 ] were located in posterior circulation. Every patient of the reported cases was managed successfully by controlling the parent arteries and totally removing the thrombosed aneurysm, and the outcomes were excellent.…”

“…There were no efficient imaging tools to differentiate between these thrombosed aneurysms and intracranial neoplasms. Conventional angiography and diffusion restriction MRI were not sufficient for differential diagnosis [ 13 , 14 , 15 , 16 ]. In our case, both studies were not done because of poor financial status of the patient.…”