Prevalence and natural history of arachnoid cysts in adults

Structural deviations of the posterior fossa and the cerebellum and their cognitive links in a neurodevelopmental deletion syndrome

High-impact genetic variants associated with neurodevelopmental disorders provide biologically-defined entry points for mechanistic investigation. The 3q29 deletion (3q29Del) is one such variant, conferring a 40-100-fold increased risk for schizophrenia, as well as high risk for autism and intellectual disability. However, the mechanisms leading to neurodevelopmental disability remain largely unknown. Here, we report the first in vivo quantitative neuroimaging study in individuals with 3q29Del (N = 24) and neurotypical controls (N = 1608) using structural MRI. Given prior radiology reports of posterior fossa abnormalities in 3q29Del, we focused our investigation on the cerebellum and its tissue-types and lobules. Additionally, we compared the prevalence of cystic/cyst-like malformations of the posterior fossa between 3q29Del and controls and examined the association between neuroanatomical findings and quantitative traits to probe gene-brain-behavior relationships. 3q29Del participants had smaller cerebellar cortex volumes than controls, before and after correction for intracranial volume (ICV). An anterior-posterior gradient emerged in finer grained lobule-based and voxel-wise analyses. 3q29Del participants also had larger cerebellar white matter volumes than controls following ICV-correction and displayed elevated rates of posterior fossa arachnoid cysts and mega cisterna magna findings independent of cerebellar volume. Cerebellar white matter and subregional gray matter volumes were associated with visual-perception and visual-motor integration skills as well as IQ, while cystic/cyst-like malformations yielded no behavioral link. In summary, we find that abnormal development of cerebellar structures may represent neuroimaging-based biomarkers of cognitive and sensorimotor function in 3q29Del, adding to the growing evidence identifying cerebellar pathology as an intersection point between syndromic and idiopathic forms of neurodevelopmental disabilities.

Unraveling Facial Nerve Palsy: A Case Series Highlighting Diagnostic and Therapeutic Challenges

Facial nerve palsy (FNP) may arise from multiple etiological reasons, including anatomical anomalies, circulatory complications, and infectious agents. This case series underscores the importance of a comprehensive diagnostic approach to identify the precise etiology, including structural abnormalities, vascular anomalies, or infectious illnesses. Here, we present three distinct occurrences of FNP, emphasizing the varied diagnostic difficulties and therapeutic strategies. It includes an arachnoid cyst, which when occurring at the cerebellopontine angle can affect multiple cranial nerves, specifically the seventh and eighth cranial nerve, a neurovascular compression syndrome, where the anterior inferior cerebellar artery loops around the facial nerve. Most often, this scenario causes hemifacial spasms, which in our scenario manifests as FNP. Lyme disease is a tick-borne disease that affects multiple cranial nerves, specifically the facial nerve. Effective management necessitates a focused treatment strategy that tackles the symptoms and the underlying disease. Advanced imaging techniques, serological tests, and a tailored treatment approach are essential for effective diagnosis, can have significant implications for patient well-being, and necessitate a thorough evaluation to identify underlying causes. This case series illustrates the diverse etiologies of FNP, emphasizing the need for comprehensive diagnostic strategies and targeted treatments. As clinicians encounter FNPs more often, this case series can help physicians understand facial palsy better. Continuous research and clinical awareness are vital for improving patient outcomes in cases of FNP.

Insular operculum disconnection and herniation into the parapharyngeal space due to a fetal Galassi Type III arachnoid cyst: a case report

Arachnoid cysts (ACs) are frequently encountered as incidental findings in the brain, with most cases being asymptomatic and not requiring intervention. However, severe brain malformations caused by ACs are rare. In this study, we describe the case of an 8-day-old female infant with a left mandibular mass that was diagnosed as an insular operculum, which has become disconnected and herniated into the parapharyngeal space through an incompletely ossified greater wing of the sphenoid, caused by a fetal Galassi Type III AC. The newborn also exhibited left hearing impairment, which did not improve at the 6-month follow-up after the cyst peritoneal shunt. This report highlights that ACs that manifest during the early fetal period may protrude from the cranial cavity through an unossified skull, potentially affecting the development of brain tissues.

Early clinico-radiological outcomes following neuroendoscopic cysto-cisternostomy for middle cranial fossa arachnoid cysts: a prospective cohort study with illustrative cases

BACKGROUND

The dysmorphogenetic arachnoid cysts' pathomechanism is most favoured, and about 50% occur as middle cranial fossa cysts (MCFAC). Still being rare, management options are yet evolving. We described the clinico-radiological features, management and early outcomes of participants with MCFAC in our service.

METHODS

This prospective cohort study involved 29 pediatric participants recruited (from electronic health records, using ICD G93.0 D016080 for arachnoid cysts) between 01/01/2023 and 31/06/2023, following informed consent according to the ethical approval. All participants had neuro-imaging confirmed MCFAC. Baseline and follow-up data were retrieved and analyzed using summary (mean, standard deviation) and inferential (ANOVA, t-test) statistics.

RESULTS

They were averagely aged 6.2 ± 4.48 years and were mostly males (89.7%). 24.1% were asymptomatic. The commonest symptoms (n = 38) were headaches (23.7%), developmental delays (15.8%), eye complaints (15.8%) and cephalomegaly (7.9%). They were predominantly left-sided (89.7%). Galassi (G) 3 lesions were less (24.1%), with G2 and G1 lesions evenly sharing the rest. The average cyst volume was 58.4 ± 80.83cm3; there were significant differences (F = 4.682; p = 0.018) between the average volumes for G1 (14.4 ± 22.42cm3), G2 (61.7 ± 89.92cm3) and G3 (122.5 ± 94.37cm3) lesions. 44.8% of the participants had rigid-endoscopic cysto-cisternotomy (all between the ICA and oculomotor nerve into the interpeduncular cistern, using ventriculostomy forceps); including all G3, 50% of G2 and no G1 (had serial clinico-radiological observation) lesion. The average pre- (117.42cm3) and post-operative (53.48cm3) cyst volumes showed significant (t = - 2.797, p = 0.021) reductions.

CONCLUSION

Middle cranial fossa arachnoid cysts occur predominantly amongst males, in middle childhood and left-sided. The treatment-related patient series are largely symptomatic, unlike the largely asymptomatic, screening-related series. Higher Galassi grade lesions presented with progressively, significantly larger cyst volumes and higher likelihoods of surgery. The average post-operative cyst volume at follow-up averagely showed almost 60% reduction from the pre-operative. All participants reported clinical remission.

Arachnoid cysts and epilepsy: seizures and epileptogenesis

Arachnoid cysts are sacs within the arachnoid membrane, filled with cerebrospinal fluid, and overwhelmingly asymptomatic; however, they can also lead to neurological symptoms such as epilepsy. The dependence of AC on epilepsy has been a subject of controversy because of studies with mixed results on whether AC contributes to seizure activity. This is a narrative review for the synthesis of available present research on the pathophysiological mechanisms of epilepsy, clinical presentation, and treatment options in patients with epilepsy and ACs. Some find no impactful association between ACs and seizures, while others point out the probable role of ACs in Epileptogenesis. Endoscopic fenestration and similar surgical interventions were found quite effective at reducing the frequency of seizures for selected patients, although not all of them achieve complete seizure control. Such a decision needs to be tailored on the basis of considerations such as localization and size of cysts and general health conditions. Future research should investigate the genetic and molecular basis of ACs and, based on large prospective long-term studies, define the AC-epilepsy relationship and refine treatment strategies in affected individuals.

Arachnoid Cysts in Athletes with Sports-Related Concussion: A Case Series and Literature Review

BACKGROUND

Arachnoid cysts (AC) are associated with a risk of rupture or haemorrhage following head impact and pose a potential predisposing factor for significant complications of sport-related concussion. Despite a recognised association between ACs and intracranial haemorrhage/cyst rupture, the risk profile of participating in contact sports with AC is not well defined. We report a retrospective case series of players presenting to the Birmingham Sports Concussion Clinic between 2017 and 2023 and underwent MRI head, with a comprehensive review of the prior literature.

RESULTS

432 athletes underwent MRI of which 11 were identified to have AC (middle fossa n = 8; posterior fossa n = 2, intraventricular n = 1). Average maximal diameter was 4.1 ± 1.2 cm. 64% had a protracted recovery (≥ 3 months). 9% experienced an AC specific complication (cyst rupture, complete neurological recovery, maximal diameter 6.5 cm, Galassi II, 4 previous concussions). 91% of patients (mean maximal diameter 3.9 ± 1.0 cm) experienced no complications despite multiple previous accumulated sports-related concussions (mean 3.3, range 1-9). Case studies from the literature are summarised (n = 63), with 98% reporting complications, none of which resulted in adverse or unfavourable neurological outcomes. Across prospective and retrospective cohort studies, 1.5% had a structural injury, and (where outcome was reported) all had a favourable outcome.

CONCLUSIONS

AC is an incidental finding in athletes, with the majority in our cohort having sustained serial concussions without AC complication. The single complication within this cohort occurred in the largest AC, and AC size is proposed as a tentative factor associated with increased risk of contact sports participation. Complications of AC appear to be a rare occurrence. This case series and review has not identified evidence to suggest that participation in sports with AC is of significant risk, though individualised assessment and discussion of the potential risks of contact sports participation should be offered.

An Unusual Case of an Intradiploic Arachnoid Cyst of the Orbit

This study reported a case of an arachnoid cyst of the sphenoid bone causing orbital signs and symptoms in a 58-year-old man with progressive proptosis and nonspecific discomfort in the OS. Orbital MRI showed a 3-cm homogeneous cyst within the left greater wing of the sphenoid bone. To the best of our knowledge, this is the first report of an intradiploic arachnoid cyst in the sphenoid bone with atypical radiological features, causing clinical symptoms, and managed through an eyelid approach, achieving a complete resolution with no complications.

Concomitant spontaneous subdural and intracystic hematoma in arachnoid cyst: a case report and review of the literature

BACKGROUND

Intracystic hematoma in arachnoid cyst are a very rare pathology that commonly occurs after head trauma, while spontaneous intracystic hematomas in arachnoid cyst associated with subdural hematoma is extremely rare. Currently there are 33 patients of spontaneous intracystic hematomas in arachnoid cyst reported in the literature. In this case report we present an adult patient with concomitant chronic subdural hematoma with intracystic hematoma in arachnoid cyst.

CASE PRESENTATION

A 19-year-old Egyptian Arabian female patient presented to the outpatient clinic complaining of severe headache of 1-month duration that was progressive in nature. Provisionally, it was thought that it might be an arachnoid cyst with associated chronic subdural hematoma along with intracystic hematoma. Decision to proceed with craniotomy and cyst evacuation was made.

CONCLUSION

Concomitant intracystic hematoma in arachnoid cyst along with subdural hematoma is a serious condition that might be life-threatening if not well managed.

Middle fossa arachnoid cyst fenestration for ruptured cysts associated with subdural collections: paediatric neurosurgery tertiary unit experience

INTRODUCTION

Arachnoid cysts are commonly encountered benign cystic structures and often come to attention as incidental findings following cranial imaging. Surgical intervention rates vary in different studies; however, rupture of cyst and subdural collection with mass effect are some of the indications for surgical intervention. In this study, we aimed to evaluate our operated cohort of middle fossa arachnoid cysts to determine the rate of traumatic subdural collection in this cohort and further assess outcomes.

METHODS

A retrospective review of all consecutive operated middle cranial fossa arachnoid cysts was carried out for the period 2010 to 2024. Demographics including age, sex, Galassi type, surgical technique for fenestration, preceding history of trauma, presence of papilloedema, and complications following surgery were extracted. Indication for surgery included papilloedema and headaches or increasing head circumference or rupture and subdural collections. Arachnoid cysts managed with CSF diversion as primary surgery were excluded.

RESULTS

Over the study period, 21 fenestrations of the arachnoid cysts were carried out in 19 patients with mean age of 7 years and M:F ratio of 2.2:1 (laterality: 9 right-sided and 10 left-sided). These included seven Galassi 2 and twelve Galassi 3 arachnoid cysts. At presentation, 10 had papilloedema, 5 with no papilloedema, and 4 with no available ophthalmological assessment. Fenestration of cyst included 12 microscopic, 6 endoscopic, and 3 combined approaches. Of the operated cohort, 8 were due to rupture of arachnoid cyst and subdural collections causing mass effect. Of 8 cases of ruptured arachnoid cyst with subdural collections, 75% had clear history of preceding head injury in the context of accidental or sports-related injuries. Two patients required redo-fenestration (10.5%), 1 patient required temporary lumbar drain (5.2%), and 2 patients required cysto-peritoneal shunts (10.5%).

CONCLUSION

Rupture of arachnoid cysts and subdural collections although rare can be associated with head injury in majority of cases. All operated cases belonged to grade 2 and 3 Galassi.

Long term clinical and radiological outcomes following surgical treatment of symptomatic cranial arachnoid cyst: A population based consecutive cohort study

OBJECTIVE

Symptomatic intracranial arachnoid cysts are treated mainly through surgical resection, endoscopic fenestration, or by implanting cystoperitoneal (CP) shunt. However, the use of a specific technique remains controversial. The purpose of this study is to discuss these surgical modalities in symptomatic patients with intracranial arachnoid cysts (ACs) and investigate which has better outcomes and less complications by comparing variable preoperative and postoperative parameters.

METHODS

An analysis of thirty-nine symptomatic patients who underwent intracranial arachnoid cyst surgery in the department of neurosurgery between 2009 and 2023 was performed. Patients were retrospectively compared based on age group, gender, anatomical location, laterality, type of intervention, clinical and volumetric changes, postoperative complications and outcome.

RESULTS

Of the 39 patients, 20 patients (51.28 %) received CP shunt. Eleven patients (28.2 %) underwent endoscopic fenestration, and 8 patients (20.5 %) had surgical resection. The age at the time of first operation ranged from 1 month to 59.9 years (mean age: 16.8 years), and the pediatric patients were 25 (64.1 %). The most common initial symptom was headache which was observed in 19 patients (48.7 %), followed by seizure in 12 patients (30.8 %), vomiting in 11 patients (28.2 %), visual dysfunction in 8 patients (20.5 %), drowsiness in 8 patients (20.5 %), visual symptoms in 8 patients (20.5 %), cognitive impairment in 4 patients (10.3 %), focal neurological deficits in 3 patients (7.7 %), and cranial nerve involvement in 1 patient (2.6 %). 24 patients (61.5 %) showed improvement while in 15 patients (38.5 %) the symptoms persisted or worsened. Postoperatively, patients were followed up for an average of one year. The highest improvement rate was noted in endoscopic fenestration with 9 improved patients (81.8 %), followed by surgical resection with 5 symptom-free patients (62.5 %). The worst outcomes were seen in cystoperitoneal shunt with only half of the patients were relieved (50 %). Complications developed in 2 patients (25 %) who underwent surgical resection, 5 patients (45.5 %) who had endoscopic fenestration, and 13 patients (65 %) who had cystoperitoneal shunting.

CONCLUSION

Endoscopic fenestration has the highest improvement rate, the lowest serious complications along with being the least invasive technique. These features make it the optimal modality in treatment of ACs. Surgical resection or cystoperitoneal shunt can be considered as secondary techniques when patients report unchanged or worsening symptoms.

Not Dandy Walker variant: a review of prominent retrocerebellar CSF space in children

The prominent retrocerebellar cerebrospinal fluid (CSF) space can be frequently encountered on paediatric neuroimaging studies. In cases involving abnormal vermian development where imaging does not align with the established criteria of Dandy-Walker malformation (DWM), the term "Dandy-Walker variant or continuum" has been historically employed to describe the aberrant posterior fossa development. Instead, the emphasis is on a more elaborate description of the findings in the posterior fossa. Moreover, combining the findings in the supratentorial brain can occasionally predict certain neurogenetic disorders that mimic Dandy-Walker phenotype. The present review demonstrates and differentiates the imaging features of various entities that result in an enlarged retrocerebellar CSF space, such as inferior vermian hypoplasia (IVH) and several neurogenetic conditions.

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.

Large intradiploic arachnoid cyst of the skull in child-a case report and new terminology proposition

We present a rare finding of the arachnoid matter invaginating into the base of middle cranial fossa and creating an abnormal space. Presented entity was incidentally found in head CT scan of 12-year-old male. Based on the radiological characteristics in CT scans and MR images, the diagnosis of intradiploic arachnoid cyst (AC) was suggested. After surgical intervention and histopathological analysis of the specimen, the diagnosis was confirmed. We assume this is the first description of large intrasphenoid AC without any traumatic or iatrogenic cause. The literature provides many different terms for the phenomenon. We are proposing the term intradiploic arachnoid diverticulum as the more accurate for capturing the essence of the phenomenon. It provides clear differentiation of the entities from classical arachnoid cysts since they are of different anatomical localization (intradural vs. extradural) and etiopathogenesis. Management with arachnoid diverticulum is not yet established, but observation with serial imaging studies should be recommended as primary management in case of asymptomatic cyst. When cyst is symptomatic, surgical treatment may be required.

Positive outcome after endoscopic treatment of a symptomatic convexity arachnoid cyst in an elderly

Cerebral convexity arachnoid cysts (ACs) only represent around 10-14% of the cysts. Symptomatic ACs in the elderly are rare. We present a 66-year-old woman with headache and a focal epileptic seizure. Imaging revealed a left parietal AC. Conservative management chosen but the patient's neurological condition worsened, and an endoscopic fenestration was then performed. Postoperatively, her symptoms completely resolved and MRI image showed significant shrinkage of the AC.

Posterior fossa microcystic meningioma mimicking an arachnoid cyst

Microcystic meningioma is an uncommon subtype of World Health Organization grade 1 meningiomas often associated with a shorter progression-free survival. Diagnosis through imaging alone can often be challenging due to atypical characteristics, especially when found in unexpected locations. Here, we present a 55-year-old woman who was diagnosed, based on imaging, with a posterior fossa arachnoid cyst 5 years prior after complaints of headaches and gait imbalance. After surgical resection of the "arachnoid cyst," the diagnosis of microcystic meningioma was made. This case report emphasizes the clinical importance and challenges associated with diagnosing microcystic meningiomas.

Effect of continuous drainage of cranial arachnoid cysts into the ventricular system by stereotactic placed catheters

Background: Surgical treatment of intracranial arachnoid cysts (iACs) is challenging. Microsurgical resection, endoscopic fenestration and cysto-peritoneal shunting are the most frequently used methods, each implying their own drawbacks. Stereotactic-guided cysto-ventricular drainage has been described as an alternative method. Here we describe our experience with this technique and how we conducted volumetric measurements to evaluate the effect of permanent drainage.Methods: Standardized stereotactic planning was performed. The planned trajectory included both the iAC and the ventricle system. The catheter was shortened to the defined length and was further fenestrated along its planned course through the iAC to allow drainage into the ventricular system. Clinical and radiological control was performed on outpatient basis after a mean follow-up of 2 (1-3) months. The overall mean follow-up was 32 months (6-59). The measurement of the cyst volume was conducted by the ABC/2-method.Results: Six patients with symptomatic arachnoid cysts (4 f, 2 m) were treated between 2010 and 2016. The overall postoperative reduction in cyst volume at the first follow-up was 36.04% (at the long-term follow-up: 38.57%). Decrease of the midline-shift was achieved in all cases and averaged 57.83% (long term: 81.88%). Clinical improvement of related symptoms could be achieved in all patients (4 patients were symptom free, two patients had alleviated symptoms). There was no case of over-drainage. The catheter had to be removed after 6 months in one case due to infection.Conclusions: We demonstrate successful symptom control and volume reduction in a small series of iACs by continuous drainage into the CSF-system through stereotactic placed catheters. This method may facilitate a self-regulated egress of entrapped cyst fluid in symptomatic patients without risk of over-drainage. A literature survey of the success rate and the complications of this approach is provided. It is concluded that this minimally- invasive method may be an alternative to established fenestration techniques especially for patients with arachnoid cysts that aren't directly adjacent to a cisternal or ventricular CSF space.

Intracranial arachnoid cyst in pregnancy: case report, literature review and evaluation of neuraxial anaesthesia risk

Choosing the type of intrapartum anaesthesia for pregnant women with intracranial arachnoid cysts can be challenging due to a lack of research. We report the intrapartum anaesthetic management of a 25-year-old woman with a known 10 cm arachnoid cyst. By means of a literature review and discussion of safety surrounding neuraxial techniques, this report will help to inform obstetric anaesthesia practice. Overall, in the absence of raised intracranial pressure, neuraxial analgesia and anaesthesia during the intrapartum period appears to be a safe option.

Purely Endoscopic Treatment for Arachnoid Cysts

Arachnoid cysts are benign, mostly congenital lesions that are asymptomatic in most patients. In some cases, due to their location or sheer size, they produce a mass effect or hydrocephalic obstruction of the cerebrospinal fluid (CSF) flow and thus might warrant surgical treatment. The goal of the surgery is usually to reduce pressure inside the cysts, to reduce the mass effect, or to restore the CSF pathway. Surgical treatment options are resection, fenestration, or shunting of the cyst. Over the past decades, treatment under sheer endoscopic control either through a tube or via craniotomy of arachnoid cysts has been studied thoroughly and replaced open microsurgical cyst surgery in the opinion of many neurosurgeons. Endoscopic treatment has proven to be a safe and feasible technique for both patients and surgeons. In the following chapter, the authors describe their indications for surgery and pre- and postoperative workup, where precautions should be taken, and discuss the different possibilities and techniques of endoscopic cyst fenestration. The aim is to give detailed instructions and present cases for ventriculocystostomy, cystocisternostomy, ventriculocystocisternostomy, and cystoventriculostomy and point out specifics deemed to be important to avoid complications and to ensure the best possible outcome for each patient.

Symptomatic, Drug-Resistant Narcolepsy Remission After Fenestration of an Arachnoid Cyst - A Case Report

Objective

The pathogenesis of different narcolepsy phenotypes remains unclear. In rare cases, narcolepsy can be attributable to secondary brain pathologies affecting the midbrain. These cases may elucidate the pathological background and the treatment of narcolepsy, but are often limited by poor objective symptom characterization and effects of therapeutic intervention, especially by modern diagnostic standards.

Methods

A young adult presented with excessive daytime sleepiness (EDS) that was refractory to classic narcolepsy medication. Diagnosis of narcolepsy was made based on the pathologically shortened sleep latencies in polysomnography and Multiple Sleep Latency Test (MSLT), together with confirmed sleep-onset REM-sleep (SOREM). Preserved hypocretin levels in cerebrospinal fluid, together with the absence of cataplectic events confirmed the diagnosis of narcolepsy type II. MRI revealed a large arachnoid cyst with compression of the midbrain.

Results

Six months after fenestration of the cyst, the patient's EDS had vastly improved. No further SOREM was observed, and polysomnographic and MSLT sleep latencies normalized. No further drug treatment was required.

Conclusion

Symptomatic narcolepsy due to space-occupying lesions in the mesencephalon comprises a unique curative treatment option. Here, surgical intervention offers an effective curative therapeutic approach. However, differential diagnosis of symptomatic narcolepsy requires special consideration.

Sports Participation and Sports-Related Neurologic Injuries in Pediatric Patients With Arachnoid Cysts

BACKGROUND

Currently, there is no consensus recommendation regarding the safety of sports participation for pediatric patients with arachnoid cysts (ACs).

OBJECTIVE

To prospectively survey patients with ACs to define the risk of sports-associated neurologic injury in untreated and treated patients.

METHODS

A prospectively administered survey was given to all patients diagnosed with an AC who presented to a single pediatric neurosurgery clinic between December 2010 and December 2021. Data were recorded on demographic information, imaging characteristics, treatment, sports participation, and presence of sports-related neurologic injury. The type and date of surgery for the AC were noted if surgery was performed.

RESULTS

Of the 303 patients with completed surveys, 189 patients participated in sports, and 94 patients had prospective data available. There was no significant difference in cyst location or Galassi score between patients who did and did not participate in contact vs noncontact sports and those who did and did not experience a concussion. A cumulative total of 2700.5 seasons of sports were played (2499.7 in untreated and 200.8 in treated patients). There were 44 sports-related concussions among 34 patients: 43 in untreated patients and 1 in a treated patient. For all participants, the concussion rate was 16.3 per 1000 seasons of all sports and 14.8 per 1000 seasons of contact sports. The concussion rate after AC treatment was 4.9 per 1000 seasons of all sports. Three patients experienced sports-related AC rupture or hemorrhage, none of which required surgery or resulted in lasting neurologic symptoms or deficits.

CONCLUSION

The rates of sports-related concussion and cyst rupture in patients with AC in both treated and untreated populations were low. We advocate for a generally permissive posture toward sports participation in this population.

Follicular carcinoma of the thyroid presenting as metastasis in the wall of an arachnoid cyst

The brain is an uncommon site for metastases of differentiated thyroid carcinoma with the most common location being cerebral hemispheres, followed by cerebellum and pituitary gland. Metastasis in the wall of an arachnoid cyst is exceedingly rare with single case report available in the published literature. Arachnoid cyst metastasis from an extraneuraxial malignancy has not been published until. We present a unique case of thyroid carcinoma metastasizing to the wall of an intracranial arachnoid cyst and the most interesting fact is that it was the first clinical manifestation of her malignancy.

Growing and symptomatic intracranial arachnoid cyst in an elderly patient: a case report and literature review

We report an elderly patient with a symptomatic and growing arachnoid cyst. Physician should be cautious in counseling asymptomatic arachnoid cyst patients, regardless of their age, and inform them of the possibility, although rare, of growth and symptom development even in their late life.

Intracranial arachnoid cysts

PURPOSE

The purpose of this review article is to outline the natural history, pathogenesis, anatomic considerations and surgical decision-making in caring for patients with intracranial arachnoid cysts.

METHODS

A review of the literature for intracranial arachnoid cysts was performed using Embase, PubMed, and Web of Science databases, including review of the bibliographies of eligible articles and the author's own experience.

RESULTS

Among those reviewed, 59 relevant original articles were included as well as illustrative cases from the authors own experience.

CONCLUSIONS

Arachnoid cysts are congenital lesions characterized by split arachnoid membrane, thick collagen in the cyst wall, absent traversing trabecular processes within the cyst, and hyperplastic arachnoid cells in the cyst wall. The underlying etiology is not entirely known, and they occur in greater proportion in males and in greater incidence with various genetic conditions including Down syndrome, mucopolysaccharidosis, schizencephaly, neurofibromatosis, autosomal dominant polycystic kidney disease (ADPKD), acrocallosal syndrome, and Aicardi syndrome. Most intracranial arachnoid cysts are incidentally found and occur in the middle cranial fossa, with the remaining occurring in the cerebellopontine angle, suprasellar cistern, quadrigeminal cistern, convexity, and posterior fossa/cisterna magna. The current article outlines the natural history, prevalence, demographic factors, and treatment decisions in managing patients with intracranial arachnoid cysts.

A quadrigeminal arachnoid cyst as a cause of neurological symptoms in an 11-month-old Brussels Griffon - A case study

An intracranial arachnoid cyst (IAC) is a rare developmental disorder that is consistent with cerebrospinal fluid accumulation between the brain and the arachnoid membrane. A quadrigeminal cyst is a specific type of cyst that is identified based on its localization. To the best of our knowledge, this is the first study to report on this type of pathology in a Brussels Griffon. This case study describes an 11-month-old female Brussels Griffon with symptoms of reluctance to lower the head and eat from a bowl placed on the ground, combined with episodes of vocalization. The patient was subsequently diagnosed with a quadrigeminal cyst during a low-field magnetic resonance imaging (MRI) exam, and she tested positive for toxoplasmosis in the blood test. Arachnoid cysts are often described as incidental findings, but the characteristics of neurological symptoms in the presented patient suggest that the cyst was clinically significant. The currently known options of pharmacological and surgical treatment give some hope for symptomatic patients, although their definitive success rate is not yet fully known.

Importance of Ophthalmological Evaluation in the Conservative Management of Increased Intracranial Pressure from a Ruptured Arachnoid Cyst

Arachnoid cysts (ACs) are cerebrospinal fluid collections between the two layers of the normal arachnoid membrane. Although they are often asymptomatic with a stationary course, eventual complications may occur. Herein, we report the case of a 9-year-old boy who developed bilateral papilloedema secondary to spontaneous rupture of an AC in the left middle cranial fossa. Although the papilloedema worsened during follow-up, his visual field remained bilaterally stable, supporting the expectant management and obviating the potential morbidity associated with neurosurgical intervention. This case report highlights the importance of a multidisciplinary approach to patients with secondary intracranial hypertension, including serial ophthalmological examinations, which provide a useful guide to surgical decision-making.

Intracranial arachnoid cysts: What is the appropriate surgical technique? A retrospective comparative study with 61 pediatric patients

Objective

Symptomatic intracranial arachnoid cysts (ACs) should be treated either through microsurgical (MS) or endoscopic surgical (ES) fenestration. Implantation of cysto-peritoneal shunt (CPS) system is another treatment option with decreasing indication. In our study, we compared the complication and revision rates between the three operative techniques in pediatric patients.

Methods

We included patients below 18 years with symptomatic intracranial ACs operated between 2004 and 2021. Initial symptoms, location, complication rate, clinical and radiological improvement, postoperative events and revision rate were compared retrospectively.

Results

Sixty-one patients; 33 (54.1%) MS operated (mean age 7.6 years), 18 (29.5%) ES operated (mean age 6.2 years) and 10 (16.4%) with CPS (mean age 3.0 years) were collected. The most common initial symptom was headache in 45.9%. 20 (32.8%) postoperative events were documented. The highest revision rate (60%) was seen in the CPS group compared to 33.3% in MS group and 16.7% in ES group. 31 patients harbored perisylvian ACs, 89% remained event-free after ES, 71% after MS and 20% after CPS. Clinical improvement immediately after surgery was observed in 58 patients (96.9% in MS, 88.9% in ES and 100% in CPS). A radiological volume reduction could be proven postoperative in 51 patients (78.8% MS, 88.9% ES and 90% CPS).

Conclusion

Endoscopic fenestration of AC is a safe and efficient technique which is being widely used nowadays with the highest event free survival compared to microsurgical fenestration especially in perisylvian arachnoid cysts. CPS shows on long terms the highest revision rate but carries the least surgical risks.

Imaging of congenital and developmental cystic lesions of the brain: a narrative review

INTRODUCTION

Congenital and developmental intracranial cysts represent a large heterogenous group with varied presentations and etiologies. They can range from normal variants to pathologic lesions often associated with known congenital syndromes or acquired insults. While some are incidentally found, others are symptomatic or may become symptomatic over time. The preferred type of neuroimaging for timely diagnosis helps determine appropriate management and treatment, if indicated.

AREAS COVERED

In this narrative review article, authors present a comprehensive description of developmental cystic lesions. Imaging descriptions are provided for each type of cystic lesion as well as several representative images.

EXPERT OPINION

As advanced neuroimaging techniques become more ubiquitous in clinical use, more light may be shed on the natural history of certain intracranial cystic lesions throughout the lifespan. This includes prenatal imaging for early identification and prognostication to surveillance imaging into advanced age to ascertain associations of certain cystic lesions with age-related cognitive dysfunction.

Computerized Tomography Texture Analysis in the Differential Diagnosis of Intracranial Epidermoid and Arachnoid Cysts

PURPOSE

This study evaluated the differences between arachnoid and epidermoid cysts in computerized tomography (CT) texture analysis (TA).

MATERIAL AND METHODS

The study included 12 patients with intracranial epidermoid cysts and 26 patients with intracranial arachnoid cysts who were diagnosed with diffusion-weighted magnetic resonance imaging (DW-MRI) and who had undergone an unenhanced CT examination before treatment. The LIFEx application software was used to obtain texture features. Eighty-two texture features from 38 lesions were automatically calculated for each lesion. The Shapiro-Wilk test was used to test the normality of the scores, and the Mann-Whitney U Test was used to test the difference between the groups. Receiver operating characteristic (ROC) curves and multivariate logistic regression modeling examined the parameters' diagnostic performances.

RESULTS

The median age of the patients was 53 years (range: 19-88 years). Eighty-two texture parameters were evaluated in the first order: gray-level co-occurrence matrix (GLCM), gray-level run length matrix (GLRLM), neighbor gray-tone difference matrix (NGTDM), and gray-level size zone matrix (GLSZM) groups. There was a statistically significant difference between the arachnoid cyst and the epidermoid cyst in the variables of compacity, compactness 1, compactness 2, sphericity, asphericity, sum average, coarseness, and low gray-level zone (p<0.05). According to the multiple logistic regression model, it was determined that the sum average in the GLCM group (B=-0.11; p=0.015), coarseness (B= 869.5; p=0.044) in the NGTDM group, and morphological sphericity (B=24.18; p=0.047) were the radiomics variables that increased the probability of epidermoid diagnosis. According to the classification table of the model, the sensitivity rate was found to be 83%, and the specificity rate was found to be 96%. Therefore, the probability of accurate model classification was 92%.

CONCLUSION

CT TA is a method that can be applied with high diagnostic accuracy in the differential diagnosis of intracranial epidermoid and arachnoid cysts, especially in patients who cannot undergo an MRI examination.

Spontaneous resorption of a convexity arachnoid cyst associated with intracystic hemorrhage and subdural hematoma: A case report

Background

Intracranial arachnoid cysts (ACs) are developmental anomalies usually filled with cerebrospinal fluid (CSF), rarely resolving throughout life. Here, we present a case of an AC with intracystic hemorrhage and subdural hematoma (SDH) that developed after a minor head injury before gradually disappearing. Neuroimaging demonstrated specific changes from hematoma formation to AC disappearance over time. The mechanisms of this condition are discussed based on imaging data.

Case Description

An 18-year-old man was admitted to our hospital with a head injury caused by a traffic accident. On arrival, he was conscious with a mild headache. Computed tomography (CT) revealed no intracranial hemorrhages or skull fractures but an AC was seen in the left convexity. One month later, follow-up CT scans showed an intracystic hemorrhage. Subsequently, an SDH appeared then both the intracystic hemorrhage and SDH gradually shrank, with the AC disappearing spontaneously. The AC was considered to have disappeared, along with the spontaneous SDH resorption.

Conclusion

We present a rare case where neuroimaging demonstrated spontaneous resorption of an AC combined with intracystic hemorrhage and SDH over time, which may provide new insights into the nature of adult ACs.

Redo Aortic Surgery in a Patient with a Large Arachnoid Cyst and Myelodysplasia

A 70-year-old man was referred for redo root and ascending aortic surgery. Preoperative investigations depicted a large arachnoid cyst occupying the left frontotemporal region and myelodysplasia with persistent thrombocytopenia. We describe successful operative management of this patient in the context of such rare intracranial pathology.

Familial and syndromic forms of arachnoid cyst implicate genetic factors in disease pathogenesis

Arachnoid cysts (ACs) are the most common space-occupying lesions in the human brain and present significant challenges for clinical management. While most cases of ACs are sporadic, nearly 40 familial forms have been reported. Moreover, ACs are seen with increased frequency in multiple Mendelian syndromes, including Chudley-McCullough syndrome, acrocallosal syndrome, and autosomal recessive primary ciliary dyskinesia. These findings suggest that genetic factors contribute to AC pathogenesis. However, traditional linkage and segregation approaches have been limited in their ability to identify causative genes for ACs because the disease is genetically heterogeneous and often presents asymptomatically and sporadically. Here, we comprehensively review theories of AC pathogenesis, the genetic evidence for AC formation, and discuss a different approach to AC genomics that could help elucidate this perplexing lesion and shed light on the associated neurodevelopmental phenotypes seen in a significant subset of these patients.

Arachnoid Cyst: A Sudden Deterioration

Arachnoid cysts are relatively rare and usually asymptomatic. It can only be diagnosed through radiological imaging modalities. Some patients may develop symptoms such as seizures, headache, dizziness, or psychiatric symptoms. We present a case of a 25-year-old male, previously healthy, who presented with sudden, repetitive episodes of seizure without regaining his consciousness. Computed tomography (CT) head scan showed a large cystic lesion that showed a rightward midline shift. Treatment was done surgically via endoscopic fenestration, and the patient remained symptom-free for one year. Most arachnoid cysts tend to remain asymptomatic throughout a patient's life span, allowing them to lead everyday normal lives; however, when these symptoms surface, they tend to be of a sudden nature requiring urgent surgical intervention. Our report follows the case of a young patient whose symptoms appear suddenly with triggers that led to status epilepticus. Our patient continued to suffer from multiple seizure attacks despite being on multiple anti-convulsive medications, and his symptoms eventually subsided via surgical intervention.

Multiomic analyses implicate a neurodevelopmental program in the pathogenesis of cerebral arachnoid cysts

Cerebral arachnoid cysts (ACs) are one of the most common and poorly understood types of developmental brain lesion. To begin to elucidate AC pathogenesis, we performed an integrated analysis of 617 patient-parent (trio) exomes, 152,898 human brain and mouse meningeal single-cell RNA sequencing transcriptomes and natural language processing data of patient medical records. We found that damaging de novo variants (DNVs) were highly enriched in patients with ACs compared with healthy individuals (P = 1.57 × 10^-33). Seven genes harbored an exome-wide significant DNV burden. AC-associated genes were enriched for chromatin modifiers and converged in midgestational transcription networks essential for neural and meningeal development. Unsupervised clustering of patient phenotypes identified four AC subtypes and clinical severity correlated with the presence of a damaging DNV. These data provide insights into the coordinated regulation of brain and meningeal development and implicate epigenomic dysregulation due to DNVs in AC pathogenesis. Our results provide a preliminary indication that, in the appropriate clinical context, ACs may be considered radiographic harbingers of neurodevelopmental pathology warranting genetic testing and neurobehavioral follow-up. These data highlight the utility of a systems-level, multiomics approach to elucidate sporadic structural brain disease.

Intracranial cysts: incidental or neurodevelopmental?

OBJECTIVES

Intracranial cysts are fluid-filled sacs within the brain. There is a diversity of intracranial cysts with different incidences in addition to the growing awareness about comorbidities and the consequences. The present study aimed to evaluate cystic findings in children who were admitted to the department of pediatric neurology.

METHODS

Children who were admitted to the Clinic of Pediatric Neurology and who had an MRI between 2016 and 2021 were evaluated. The MRI examination was performed with the pediatric epilepsy protocol. Children with primary intracranial cysts were enrolled in the study. Demographic and clinical findings were evaluated from the hospital's database and patients' files.

RESULTS

Among the 78 patients, 36 (46.2%) were male and 42 (53.8%) were female. The mean age was 7 ± 5.4 years. The most frequent presenting complaint was a seizure (47.4%). Approximately one-quarter (28.2%) had mental and/or motor retardation. Nine (11.5%) of the children had a neuropsychiatric diagnosis. Most of the cysts were located at the midline (41%) with the majority located extra-axial (71.8%) and supratentorial (78.2%). Arachnoid cysts were observed most frequently with a percentage of 64.1%, followed by pineal cysts (15.4%). The history of seizure, epilepsy, presence of mental retardation, and neuropsychiatric problems were evaluated according to the population ratios based on z approximation in which significantly higher rates were observed among cases with intracranial cysts.

CONCLUSION

Intracranial cysts should be taken into consideration for comorbid pathologies, especially in the childhood period. Early evaluation in patients with intracranial cysts for developmental delay and neuropsychiatric problems is important.

Epilepsy-associated open-lip schizencephaly with arachnoid cyst: a rare case report

Background

Schizencephaly is a rare congenital cerebral malformation characterized by clefts in the cerebral cortex. The traction effect and splitting of leptomeninges caused by schizencephaly potentially formed an arachnoid cyst.

Case presentation

We present a case of an 18-year-old male with history of several episodes of complex partial seizure over the last 2 months, with an electroencephalogram signified an epileptic form in the right temporal lobe. Brain magnetic-resonance imaging revealed an arachnoid cyst in the right temporal fossa and a grey matter-lined right temporal cleft consistent with open-lip schizencephaly. To the best of authors’ knowledge, only two previous similar cases have been reported in 1997. Our patient underwent cystoperitoneal shunt and was given double anti-epileptic agents, which successfully resolved and prevented the seizure episode during further follow-up.

Conclusion

New onset of seizure-associated schizencephaly in adult are very rare. In this case, space-occupying lesions effects from the enlarged arachnoid cysts caused seizure, which resolved after the cystoperitoneal shunt and double anti-epileptic agents.

Effect comparison of neuroendoscopic vs. craniotomy in the treatment of adult intracranial arachnoid cyst

Purpose

Intracranial arachnoid cysts are common, accounting for about 1%-2% of intracranial space-occupying lesions. There is controversy over the method of surgical intervention, and in order to provide guidance for surgical decision making, this study compares the efficacy of craniotomy vs. neuroendoscopic surgery in treating arachnoid cysts.

Methods

The adult patients with arachnoid cyst admitted to our department from October 2016 to August 2021 were retrospectively analyzed. Thirteen adult patients were recruited, and divided into two groups: neuroendoscopic group (group A) and craniotomy group (group B). We compared the gender, age, clinical symptoms, preoperative and postoperative cyst sizes, symptom improvement, complications, length of hospital stay, and hospital costs between two groups to analyze the therapeutic effects of these two surgical methods.

Results

The cost of hospitalization in group A was significantly lower than that in group B (47,292.8 vs. 65,151.8 yuan, P < 0.05), and there was no difference in the length of hospital stay between the two groups. The preoperative cysts in group A were significantly larger than those in group B (6.38 vs. 2.97 cm, P < 0.05). In groups A and B, the short-term symptom improvement rates were 100% and 75.0%, respectively. The long-term symptom improvement rates were 77.78% and 75.0% (P > 0.05), respectively.

Conclusion

Both neuroendoscopic and craniotomy have good curative effects for the treatment of intracranial arachnoid cysts. There was no significant difference in the outcomes between the two surgical techniques. The cost of hospitalization can be reduced with neuroendoscopic surgery. Neuroendoscopic treatment is recommended for large intracranial arachnoid cysts, and craniotomy is suitable for small intracranial arachnoid cysts.

Temporal sylvian fissure arachnoid cyst in children: treatment outcome following microsurgical cyst fenestration with special emphasis on cyst reduction and subdural collection

OBJECTIVES

Controversy remains regarding surgical managements of sylvian fissure arachnoid cyst (SFAC). This review presents our experience in the microsurgical fenestration of pediatric patients with SFAC to define surgical indication, and risks and benefits with special emphasis on postoperative subdural fluid collection (SDFC) and cyst size reduction.

METHODS

Thirty-four children with SFAC who underwent microsurgical cyst fenestration at a single institution over a 10-year period were retrospectively reviewed for their clinical presentation, neuroimaging findings, and postsurgical course. The SFACs were classified by a novel grading system based on the degree of arachnoid cyst extension from the sylvian fissure to the insular cistern shown on MR images: grade 0 - little or no prominence of sylvian fissure, grade I - SFAC confined to the sylvian fissure, grade II - SFAC partially extending to the insular cistern, grade III - SFAC extending to the entire insular cistern.

RESULTS

There were 26 males and 8 females. SFAC was present in the left side in 24. Twelve patients presented with cyst rupturing to the subdural space. Cyst grading did not show significant difference compared with rupture status (p > 0.9). All patients underwent microsurgical cyst fenestration. Postoperative SDFC is common but often resolved overtime in two-thirds of the cases with the mean average of 6 months. However, 3 patients had symptomatic postoperative SDFC and needed reoperation shortly after the first operation. Microsurgical cyst fenestrations for SFAC effectively resolved the presenting symptoms and often showed restorations of intracranial structures on follow-up imaging. Cyst resolution or reduction greater than 75% was noted in 61.8% of the patients postoperatively which was noted in a half of the SFAC of children even with age of 11 years or older. During the follow-up, no cyst recurrence or SDFC was noted. Patients with greater surgical reduction of cyst size tended to occur in younger children, and those with lower MR grade.

CONCLUSION

Our results showed a high reduction rate of SFAC and brain re-expansion after microsurgical fenestration together with symptomatic improvements regardless the patient's age. Considering the developing CNS during childhood, reductions of a large space-occupying lesion followed by restorations of the structural integrity of the developing brain are very desirable. However, a multi-center cooperative prospective longitudinal study on long-term comparative data of those treated and untreated of neuro-psychological outcome and cyst rupture incidence is needed.

Surgical indications in pediatric arachnoid cysts

INTRODUCTION

Arachnoid cysts are developmental lesions consisting of CSF collections within the subarachnoid space. There are many theories and hypotheses about their pathogenesis and histopathology and this may also explain the diversities seen in clinical behaviors of these cysts, their natural history and consequently their management where there is a great controversy about selecting patients for surgical intervention. The most common location in pediatrics is the Sylvian or middle cranial fossa and this made it gain more concern and greater debate about its management where its diagnosis is often accidently or associated with nonspecific symptoms.

AIM

Our aim in this article was to review the main surgical indications for pediatric arachnoid cysts in the literature.

CONCLUSION

We concluded that the decision for surgical intervention for pediatric arachnoid cysts is not a simple one and highly debatable and should be taken cautiously especially with sylvian arachnoid cysts that may reach a large size without symptoms. However, there is a consensus that the occurrence of symptoms definitely correlated to the presence of these cysts or their rupture with consequent subdural hematoma or hygroma are indications for surgical intervention. Large cysts in locations compressing CSF pathways causing hydrocephalus are also candidates for surgical fenestration. The surgical gain from prophylactic surgery is questionable particularly when asymptomatic.

Right Trochlear Nerve Palsy as an Uncommon Manifestation of Arachnoid Cyst

The majority of arachnoid cysts are congenital intracranial lesions that develop in the early embryonic stages as a result of a slight irregularity in the cerebrospinal fluid's (CSF) passage through the embryonic mesenchyme. Most of the time, these cysts are asymptomatic all throughout life. Diplopia caused by an arachnoid cyst is extremely rare. We present a rare event of isolated fourth nerve palsy in a 56-year-old woman brought on by an intracranial arachnoid cyst. Her only presenting symptom was vertical diplopia for one week. She denied any history of trauma. Ocular motility revealed limitation of abduction in her right eye. We proceeded with neuroimaging and the magnetic resonance imaging (MRI) confirmed the presence of a well-circumscribed left retro-cerebellar lesion which follows the CSF signal intensity in all sequences causing compression onto the posterior aspect of the left cerebellum, keeping with the diagnosis of an arachnoid cyst. This uncommon pathology tends to be difficult to diagnose and treat.

Ruptured Sylvian arachnoid cysts: an update on a real problem

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.

Understanding intracranial arachnoid cysts: a review of etiology, pathogenesis, and epidemiology

Arachnoid cysts (AC) are one of the common pathologies encountered in pediatric neurosurgical settings. It comes to clinical attention more often incidentally but also more often than previously due to the wide availability of diagnostic imaging. However, the accurate incidence and prevalence remain unknown. There is an ongoing debate on symptomatology, indications of treatment, and best treatment modalities. In this review, we aimed to discuss the current general knowledge about the arachnoid cyst, focusing on the etiology, pathogenesis, and epidemiology. Specific findings related to locations, such as the Sylvian fissure, are also emphasized.

Postnatal Posterior Fossa Arachnoid Cyst: A Developmental Etiology to Be Considered

Intracranial arachnoid cyst is the most common cystic congenital anomaly in the brain. In this study, we discuss a pregnancy that had serial fetal ultrasound scans throughout the pregnancy and a fetal anomaly scan at 24 weeks of gestation that was normal. The child was born healthy with normal development, but 12 months onward the head began to enlarge. The magnetic resonance imaging of the brain showed a large posterior fossa arachnoid cyst with hydrocephalus. We discuss the postulation to explain this pathogenesis of the cyst. This case highlights that not all symptomatic arachnoid cysts are congenital despite the manifestation being as early as infancy.

Nonneoplastic and noninfective cysts of the central nervous system: A histopathological study

Nonneoplastic epithelial cysts involving the central nervous system are diverse and are predominantly developmental in origin. This study represents a surgical series describing the histopathological features of 507 such epithelial cysts with clinical and imaging correlation. Age at surgery ranged from 7 months to 72 years (mean: 33 years) affecting 246 male and 261 female patients. Colloid cyst was the most frequently resected cyst, followed by epidermoid cyst, arachnoid cyst, Rathke cleft cyst, dermoid cyst, neurenteric cyst, Tarlov cyst, and choroid plexus cyst. Diagnosis was based on the location of the cysts and the nature of the lining epithelium. Rathke cleft cyst showed the highest propensity for squamous metaplasia, significant inflammation, and xanthogranulomatous reaction. Ulceration of lining epithelium and calcification were most frequent in dermoid cyst. Radiopathological concordance was maximal for colloid cyst, followed by epidermoid and arachnoid cysts. Epidermoid and dermoid cysts exhibited the highest propensity for local tumor progression, followed by Rathke cleft cyst.

Intracranial drainage versus extracranial shunt in the treatment of intracranial arachnoid cysts: a meta-analysis

OBJECTIVE

To review the literature and analyze the efficacy and safety of two surgery procedures, intracranial drainage and extracranial shunt, for intracranial arachnoid cysts.

METHODS

We searched the online Medlars, PubMed, and Cochrane Central electronic databases and collected studies of patients with intracranial arachnoid cysts treated with two surgical methods.

RESULTS

The meta-analysis results shows that there were not statistically significant in clinical symptoms improvement, cyst reduction, the improvement of epilepsy, epidural hematoma, cerebrospinal fluid leak, and recurrence rate (P > 0.05, with RR values are 0.99, 0.94, 1.00, 0.94, 1.21, and 0.75 respectively). There was statistically significant in the occurrence rate of intracranial infection (P = 0.0004, RR = 0.28). The intracranial drainage group was lower than extracranial shunt group.

CONCLUSION

The results indicated that the efficacy and safety of two surgery procedures are similar in the treatment of intracranial arachnoid cysts, but the intracranial drainage was better than extracranial shunt in reducing the risk of intracranial infection.

Optic nerve ultrasonography in the evaluation of the relationship between arachnoid cyst and headache

AIM

This study is aimed to show the difference between optic nerve sheath diameter (ONSD) values in migraine patients with and without arachnoid cysts from migraine patients and control groups, and to evaluate the relationship with the arachnoid cyst size on magnetic resonance imaging (MRI) and their clinical severity.

METHODS

This cross-sectional study included pediatric patients who were previously diagnosed with migraine and the control group. The patients consist of 3 groups. The first group was 24 patients with arachnoid cysts on brain magnetic resonance imaging (MRI) who met the diagnostic criteria for migraine (group 1); the second group was 20 patients with only headache without arachnoid cysts or other findings on brain magnetic resonance imaging (MRI) (group 2); the third group was completely healthy 20 control group. Demographic data of the patients, the onset of headache time, clinical severity, electroencephalography (EEG) findings, optic nerve sheath diameter (ONSD) measurements by ultrasonography, and the volume of arachnoid cyst on brain MRI were determined and compared.

RESULTS

The optic nerve sheath diameter (ONSD) value was the highest in group 1 and the lowest in the control group (p: 0.001). The clinical severity was statistically different between the groups (p: 0.038). Accordingly, the majority of the clinical severity of group 1 was determined in grades 3 and 4. A weak positive correlation was found between the arachnoid cyst size on MRI and the ONSD measurement (r = 0.410, p = 0.047). The ONSD value statistically significantly increased with clinical severity in group 1 (p: 0.003).

CONCLUSION

The reliability of the optic nerve sheath diameter (ONSD) measurements in determining the increase of the intracranial pressure was shown in previous studies. This is the first study in the literature presenting that the intracranial pressure effects of arachnoid cysts can be demonstrated by ONSD. We have considered that arachnoid cysts detected in headaches can create a compression effect and cause the pain to intensify.