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

Abstract

BACKGROUND Perianeurysmal cysts in the brainstem after endovascular coil embolization are rare, and their underlying mechanism remains unclear. The authors reported a case of a postcoiling perianeurysmal cyst that developed 6 years after endovascular coil embolization for a ruptured aneurysm and reviewed the related literature. OBSERVATIONS A 77-year-old woman had a history of subarachnoid hemorrhage 6 years earlier. The ruptured large left vertebral artery–posterior inferior cerebellar artery aneurysm was treated with endovascular coil embolization. Two years later, the aneurysm regrew and perianeurysmal brainstem edema was detected on magnetic resonance imaging (MRI); stent-assisted coil embolization combined with low-flow bypass was performed. Follow-up MRI showed that the perianeurysmal edema gradually transformed into a perianeurysmal cyst over the next 3 years. Finally, the perianeurysmal cyst caused gait disturbance with ataxia, and the patient received cyst puncture. After surgery, the symptom was immediately improved. LESSONS The authors reported, for the first time, postcoiling of perianeurysmal cyst formation treated by cyst puncture. If perianeurysmal edema is detected after endovascular coil embolization, especially for large aneurysms, it is necessary to consider progression to cyst formation and follow up over time. In addition, cyst puncture is effective, depending on the symptoms and the lesion.

Neuroendoscopic cyst fenestration for delayed enlargement of perianeurysmal cyst formation through long-term follow-up after endovascular treatment: A case report and review of literature

“…Moreover, in recent reports of perianeurysmal cysts after endovascular treatment, increasing reactive inflammation of the aneurysmal wall and increasing brain compliance after endovascular treatment lead to cystic encephalomalacia due to direct pressure and pulsatile from the postcoil embolization aneurysm to the adjacent brain tissue are also suggestive mechanisms. [2,8,10] Furthermore, a previous report has suggested an association between cyst formation and hydrogel-coated coils. [1] It is noteworthy that in cases of perianeurysmal cysts following endovascular treatment of aneurysms, most postendovascular cerebral aneurysms recur, requiring additional treatment.…”

“…Notably, ten patients had a history of endovascular treatment for cerebral aneurysms before being diagnosed with perianeurysmal cysts, as in the present case. [1,5,6,10,[12][13][14]18] In addition, nine of these cases showed aneurysm recurrence after endovascular treatment at the time of cyst appearance or during the disease. is suggests that the development of perianeurysmal cysts may be influenced by the endovascular treatment of the aneurysm itself or by changes within the aneurysm, such as thrombosis and recurrence after treatment.…”

“…[19] Perianeurysmal cyst formation associated with ruptured or unruptured cerebral aneurysms is extremely rare, with only 22 cases reported in the literature [Table 1]. [1][2][3][6][7][8][10][11][12][13][14][18][19][20] Most cases occurred in the elderly average 61.3 years and were slightly more common in men (male: female, 14:8). Most cases were associated with aneurysms in the anterior circulation (internal carotid artery, five cases; middle cerebral artery, five cases; and Acom A, five cases); however, they also occurred in the posterior circulation (posterior cerebral artery, three cases; basilar artery, two cases; and vertebral artery-posterior inferior cerebellar artery, one case).…”

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

“…Three cases describe fenestration into a ventricle either endoscopically or via craniotomy; only one case required a further fenestration [ 6 , 10 , 13 ]. A less invasive option is chronic drainage via cysto-peritoneal shunt or Ommaya, although the risk of shunt occlusion is not trivial given the typically highly proteinaceous cyst fluid; Friedman et al report (asymptomatic) cyst recurrence despite shunting [ 4 , 9 ]. The second treatment strategy involves reduction in cyst fluid production, which may be accomplished by irradiation or gentle cyst wall coagulation as performed in the current case [ 6 ].…”

“…Nearly half of the perianeurysmal cysts were diagnosed following endovascular aneurysm treatment (n=13/28) [ 1 , 4 - 6 , 9 , 10 , 12 - 14 , 18 , 19 ]. Notably, the remainder of were diagnosed concurrently with an associated aneurysm (n=15/28); none were diagnosed post-clipping [ 2 , 3 , 7 , 8 , 11 , 15 - 17 ].…”