Intracranial perianeurysmal cysts: case series and review of the literature

Abstract

BackgroundIntracranial perianeurysmal cysts are a rare finding associated with cerebral aneurysms. Patients may present with symptoms secondary to mass effect from perianeurysmal cysts requiring drainage. These lesions can masquerade as neoplasms if dedicated vascular imaging is not performed, leading to misdiagnosis.MethodA retrospective search of our database was done for intracranial aneurysms that have been treated between 1998 and 2020. A literature search was then performed on PubMed and Google Scholar with the search terms ‘aneurysm’, ‘intracranial/intracerebral’, ‘cyst’, and ‘perianeurysmal cyst’. Patient demographics, aneurysms and cysts characteristics were then summarized as a table and in the discussion.ResultsThree cases where intracranial aneurysm had associated perianeurysmal cysts were found in our database. Combined with the available literature a total of 19 cases of perianeurysmal cysts have thus far been reported since this entity was first described in 2002. A significant number of perianeurysmal cysts (5/19) required intervention. In 5/19 cases the patient presented with a perianeurysmal cyst without a history of subarachnoid hemorrhage. Of the 10 cases where aneurysm follow-up was reported there were 5 cases where there was aneurysm recurrence necessitating re-treatment.ConclusionSignificant variability exists in the patient demographics, aneurysm and cyst characteristics of perianeurysmal cysts. This suggests that there is no single unified etiology and pathogenesis. These lesions are a rare finding and at present do not appear to carry diagnostic or prognostic significance. Management of perianeurysmal cysts is case-dependent and intervention should be considered when treating the related aneurysm, especially in patients with secondary symptoms.

Perianeurysmal cyst formation in the brainstem after coil embolization: illustrative case

“… 3 However, the frequency of hydrocephalus was high, in the range of 15.2% to 18.7%. 1 Perianeurysmal edema and aseptic meningitis are rare but have also been reported in cases of hydrogel-coated coils in other reports. 4–6 Perianeurysmal edema and hydrocephalus were also reported after the use of bare platinum coils; 7 therefore, it is not considered to be due to the hydrogel itself.…”

“…The mechanism of perianeurysmal cyst formation is not well known because only 19 cases of perianeurysmal cyst formation after endovascular coil embolization have been reported. 1 …”

“…The mechanism of perianeurysmal cysts has been reported to be related to previous hemorrhage, ischemic encephalomalacia, inflammation associated with thrombus formation and cytokines, and angiogenic factors. 1 , 12–16 Based on these considerations, perianeurysmal edema and perianeurysmal cysts have similar mechanisms and may be related phenomena.…”

“…Cyst formation in the perianeurysmal brain tissue after endovascular coil embolization is a rare complication and is termed a “perianeurysmal cyst.” Only 19 cases of perianeurysmal cyst have been reported. 1 We present a case of symptomatic perianeurysmal cyst in the brainstem that developed 6 years after endovascular coil embolization for a ruptured left vertebral artery–posterior inferior cerebellar artery (VA-PICA) aneurysm.…”

Symptomatic perianeursymal cyst development 20 years after endovascular treatment of a ruptured giant aneurysm: Case report and updated review

“…2)3)7)8)11) [15][16][17] This is an update to a recent review demonstrating that the majority (n=14/19) of perianeurysmal cysts were diagnosed simultaneously with an associated aneurysm rather than following treatment. 12) 25.9% (n=7/27) of patients had prior aneurysm rupture; all were treated endovascularly. Of those who underwent endovascular intervention (n=15), the majority (n=11) experienced aneurysm residual or recurrence requiring more than one treatment.…”