Arachnoid cyst of the velum interpositum originating from tela choroidea

Arachnoid cyst in the pediatric patient: What the radiologist needs to know

Arachnoid cysts are the most common incidentally discovered intracranial lesions on imaging and the most common cystic intracranial lesions. They may be developmental or secondary. A relative lack of recent literature and any comprehensive radiological review on arachnoid cysts has led to a general lack of awareness among radiologists of symptomatic or complicated arachnoid cysts. This is particularly concerning in pediatric patients. While arachnoid cysts are asymptomatic in most cases, they can cause clinical symptoms in a minority of cases, especially when they occur in unusual sites. These include intraventricular locations where they may cause hydrocephalus, the basal cisterns where they may compress cranial nerves, the cerebellopontine angle where they have to be differentiated from a number of cystic lesions, the cavum septum pellucidum or cavum velum interpositum, the choroid fissure where they can entrap the temporal horn and compress the hippocampus, the posterior fossa where they need to be differentiated from other posterior fossa cystic lesions, and within the spinal canal where there is a concern for cord or nerve root compression. Larger cysts are more prone to complications such as mass effect, hemorrhage, and rupture. Hemorrhage and rupture often present with acute symptoms. Ruptured cysts lose their characteristic imaging appearance and can mimic several ominous pathologies. It therefore becomes vital to accurately diagnose these cases as complications of pre-existing arachnoid cysts for appropriate management. A detailed review of all diagnostic imaging aspects of arachnoid cysts will help fill in the existing information void on this important entity.

The efficacy of cystoperitoneal shunting for the surgical management of intracranial arachnoid cysts in the elderly: A systematic review of the literature

Background:

Intracranial arachnoid cysts (AC) are benign, cerebrospinal fluid filled spaces within the arachnoid layer of the meninges. Neurosurgical intervention in children and young adults has been extensively studied, but the optimal strategy in the elderly remains unclear. Therefore, we performed a single center retrospective study combined with a systematic review of the literature to compare cystoperitoneal (CP) shunting with other surgical approaches in the elderly cohort.

Methods:

Retrospective neurosurgical database search between January 2005 and December 2018, and systematic review of the literature using PRISMA guidelines were performed. Inclusion criteria: Age 60 years or older, radiological diagnosis of intracranial AC, neurosurgical intervention, and neuroradiological (NOG score)/clinical outcome (COG score). Data from both sources were pooled and statistically analyzed.

Results:

Our literature search yielded 12 studies (34 patients), which were pooled with our institutional data (13 patients). CP shunts (7 patients; 15%), cyst fenestration (28 patients; 60%) and cyst marsupialisation/resection (10 patients; 21%) were the commonest approaches. Average duration of follow-up was 23.6, 26.9, and 9.5 months for each approach, respectively. There was no statistically significant association between choice of surgical intervention and NOG score (P = 0.417), COG score (P = 0.601), or complication rate (P = 0.955). However, CP shunting had the lowest complication rate, with only one patient developing chronic subdural haematoma.

Conclusion:

CP shunting is a safe and effective surgical treatment strategy for ACs in the elderly. It has similar clinical and radiological outcomes but superior risk profile when compared with other approaches. We advocate CP shunting as first line neurosurgical intervention for the management of intracranial ACs in the elderly.

Pediatric intraventricular arachnoid cysts in the body of lateral ventricle: surgical outcome and its embryologic background

PURPOSE

The aim of this study is for the surgical treatment and outcome of the endoscopic fenestration of the arachnoid cyst located in the ventricular body to trigone in the pediatric population. Special concern was paid for the developmental origin of the intraventricular cysts estimated from the postoperative follow-up neuroimagings.

PATIENTS AND METHODS

Between July 2002 and June 2015, we performed endoscopic and partly CT/MRI navigated fenestrations of intraventricular arachnoid cysts located at the body to trigone of the lateral ventricle in ten pediatric patients aged 2 months to 5 years. Based on the long axis of the cyst, we have opted for two surgical approaches: anterior approach via burr hole at Kocher's point and posterior approach via burr hole at the posterior occipital region. Fenestration was performed based on the intraoperative findings, either ventriculocystostomy, ventriculocystoventriculostomy, or ventriculocystocisternostomy.

RESULTS

Intraventricular arachnoid cysts located in the body-trigone region showed a favorable outcome after endoscopic fenestration. All of the cysts shrank postoperatively. Follow-up neuroimagings taken between 6 and 126 months after surgery strongly suggested its relationship with the midline cisterns. Of our ten cases, eight were suggestive for originating from the velum interpositum cistern while two seemed to root from the quadrigeminal cistern.

CONCLUSION

In the present study, we found that endoscopic fenestration of intraventricular arachnoid cysts in the body to trigone is a safe procedure with a satisfactory outcome. In our limited experience, there are two anatomic backgrounds; velum interpositum cistern and quadrigeminal cistern. Differentiation can be possible by neuroimagings, especially those obtained after surgery.

Arachnoid cyst of the cavum velum interpositum in a septuagenarian: radiological features and differential diagnosis

The cavum velum interpositum (CVI) is a thin, triangular-shaped cerebrospinal fluid (CSF)-filled space between the lateral ventricles that lies below the fornices and above the third ventricle. It is a normal variant seen in premature and newborn infants and usually disappears with brain maturation. CVI is rarely seen in adults as a persistent primitive structure. Although moderate cystic dilatation of the CVI may sometimes be observed, a true large cyst is extremely rare with only a handful of reported cases, mostly in children and adolescents. We describe the case of CVI arachnoid cyst diagnosed on imaging in a septuagenarian with the complaint of occasional headaches.