Ruptured Sylvian arachnoid cysts: an update on a real problem

Abstract

Purpose Sylvian arachnoid cysts (SACs) are the most common type of arachnoid cysts and the most prone to undergo a rupture. This event is considered rare but potentially severe. No definite information is available on its occurrence or management. The goal of the present article is to provide an update on the epidemiological, etiological, and clinical aspects and the management of this peculiar clinical condition. Methods A comprehensive review of the English literature of the last 40 years on this topic has been realized. Moreover, a personal series of children investigated and treated in the last 20 years is presented. These patients were managed as follows: (1) treatment of the subdural collection; (2) identification of candidates for surgical treatment of the residual cyst (brain MRI, perfusion brain MRI, prolonged invasive ICP monitoring (selected cases), EEG, neuropsychological tests); (3) surgical treatment of the cyst in the patients with pathological perfusion MRI and/or ICP measurement and/or clear neurophysiological and neuropsychological correlations. Results A total of 446 patients (430 from the literature and 16 from the personal series), mainly children, adolescents, and young adults, have been analyzed leading to the following results: (1) SAC rupture is rare but not negligible (yearly risk of rupture: 0.04%; overall risk up to 10% in children affected by SCAs). Prophylactic surgery in asymptomatic cases is not advisable. (2) The mechanism of rupture is not known but an impact of SAC against the sphenoid wing and/or a direct injury on SAC through a thinned temporal bone, with possible laceration of the cyst wall vessels and/or tear of the bridging veins, can be hypothesized. A head injury is often not reported (may be misdiagnosed). (3) Subdural collection (hygroma > chronic hematoma) is the most common finding followed by intracystic bleeding, extradural hematoma, and other types of bleeding. Signs or symptoms of raised intracranial pressure are the most frequent ones. (4) The complication of the rupture is usually treated in emergency or in the acute period by burr hole or craniotomic evacuation of the subdural collection, although a conservative management is possible in some cases. Following the rupture, the majority of SACs are treated (70%), often at the same time of the complication, but no specific investigations are routinely performed to select candidates. According to our protocol, only 43.7% of SACs needed to be treated. Conclusions The “spontaneous” or posttraumatic rupture of SACs is a rare but potentially significant complication followed by a generally good outcome. The course of the cyst is independent from the outcome of the complication, consequently requiring specific investigations for individuating those lesions interfering with CSF dynamics and/or cerebral blood flow.

Arachnoid Cyst Burst in Presence of Contralateral Nomura IV Subdural Hematoma: After Effects of Traumatic Kickback and Intracranial Pressure

“…The abrupt rupture of the cyst wall contributed on the one hand to fill the subdural space with CSF (hygroma) but also to create a possible communication breach with the arachnoid space that promoted the filling and expansion of the hygroma itself [30]. In view of the proximity of cyst middle wall to the temporal lobe, arachnoid breach could have connected the subdural space with the Silvian cistern, with continuous hygroma replenishment [20]. SDGs are characterized by a fluid content that may be clear, sometimes blood-tinged or xanthochromic, due to the rupture of inflammatory and vascularized membranes (hematohygroma) [8].…”

“…One of the most common hypotheses is the splitting of the arachnoid membrane during embryogenic development of subarachnoid cisterns [8]. Being most asymptomatic the diagnosis is like incidental findings in 25% of cases and the treatment choice is conservative management [16][17][18][19][20]. When symptomatic these can cause headaches, seizures, visual disturbances, gait disturbances, nausea, vomiting, developmental delays (in children) and changes in behaviors.…”

Radiologic Follow-up of Ruptured Arachnoid Cysts With or Without Hemorrhage: Five Case Reports and a Review of the Literature

“…There is no consensus on the optimal treatment of ruptured arachnoid cysts, which depends on the symptom pattern and cyst location. Observation is possible in most patients with no symptoms or mild symptoms because arachnoid cysts associated with subdural or epidural hematomas may also spontaneously resolve [ 7 8 9 12 13 ]. If arachnoid cysts do not resolve spontaneously, burr-hole subdural drainage, craniotomy and cyst fenestration, and endoscopic cyst fenestration are the neurosurgical options [ 9 10 ].…”

Spontaneous rupture of arachnoid cyst

“…Massimi et al . [ 6 ] mentioned up to 106 cases of spontaneous rupture on retrospective analysis in 2022. Structurally, ACs are surrounded by an arachnoid sheet and may be primary (congenital) or secondary (to trauma, meningitis, or surgery).…”

“…The medicolegal aspects of such a scenario may result in medical malpractice or delay in treatment. [ 10 ] The Galassi classification [ 6 ] of MCF ACs was described in 1982 and divides these cysts into three types: (I) Small, spindle-shaped, and limited to the anterior portion of MCF, freely communicating with subarachnoid space (SAS); (II) superior extent along the Sylvian fissure, displacing temporal lobe, communicating with SAS; and (III) large cyst filling the MCF displacing frontal temporal and parietal lobes, often excluded from CSF communication with SAS.…”