Quadrigeminal arachnoid cyst: Factors affecting outcomes and complications in a large series of cases

Arachnoid cysts constitute approximately 1 % of intracranial mass lesions, with quadrigeminal cistern arachnoid cysts being 5-18 % of those. This study presents a series of 31 cases of quadrigeminal cistern arachnoid cysts, constituting the most extensive series reported to date.

A retrospective analysis was conducted on 31 patients diagnosed with quadrigeminal cistern arachnoid cysts, focusing on clinical presentation, demographics, treatment approaches, and outcomes. Patient ages ranged from 6 m to 45 years, with a mean age of 29. The cysts were classified into three subtypes based on MRI findings, and all patients underwent surgical intervention.

Of the 31 patients, 7 had Type 1 cysts, 12 had Type 2 cysts, and 12 had Type 3 cysts. For patients with Type 1 cysts, endoscopic third ventriculostomy with cyst fenestration was done in 6 cases, with craniotomy in 1 one case. In those with Type 2 cysts, Shunt was done in 3 cases: craniotomy with cyst wall excision in 4, ETV alone in 3, and cyst fenestration in 2. For Type 3 cysts, 11 patients underwent endoscopic fenestration to the subarachnoid space or ventricles, combined with endoscopic third ventriculostomy, and craniotomy was done in one case. All three shunts, one craniotomy, and 2 ETV with fenestration needed revision surgery due to symptoms(6/31 cases). Three cases had an intraventricular haemorrhage, with 2 cases needing external drainage. Four of the six revision cases showed no reduction in cyst size on MRI after the first surgery.

Quadrigeminal plate arachnoid cysts typically present with symptoms and necessitate surgical treatment. Our findings show that Type 2 and 3 cysts are the most common. Shunts are NOT indicated as the first procedure, as they have poor results. Endoscopic fenestration with ETV remains the procedure of choice, while ETV alone may suffice in most cases. Bleeding and infection reduce success rates.