Intracranial arachnoid cysts: Current concepts and treatment alternatives

Cognition in children with arachnoid cysts - A five-year follow-up after microneurosurgical fenestration

BACKGROUND AND PURPOSE

In recent years there has been a re-evaluation regarding the clinical implications of temporal lobe arachnoid cysts (temporal arachnoid cysts) in children. These cysts have often been considered asymptomatic, or if symptomatic, only causing focal neurological symptoms or signs of increased intracranial pressure. However, several studies have more recently reported on cognitive symptoms improving after surgery. This study aimed to evaluate if reported cognitive improvement after surgery of temporal arachnoid cysts were stable after five years.

METHOD

Ten consecutive children (m = 14.65; range 12.1-19.415 were assessed cognitively five years after micro-neurosurgical fenestration of a temporal arachnoid cyst. Results were compared to results from their pre- and post-surgical evaluations. Evaluations included the Wechsler-scales, Boston Naming Test (BNT), Rey Auditory Verbal Learning Test (RAVLT), verbal fluency test (FAS) and Rey Complex Figure Test (RCFT).

RESULTS

The analysis revealed significant postsurgical improvement compared to baseline on the Wechsler-scales measures of general intelligence (FSIQ), verbal abilities (VCI) and processing speed (PSI). Mean differences after surgery were 8.3 for FSIQ, (p = 0.026), 8.5 for VI (p =  < .01) and 9.9 for PSI (p = 0.03). There were no significant differences in mean test results when comparing postsurgical scores with scores five years after surgery, indicating long-term stability of improvements.

CONCLUSION

The results indicate that affected cognitive functions in children with temporal arachnoid cysts improve after surgery and that the improvements remain stable five years later. The improvements and long term stability were also consistent with the experience of both parents and children. The findings provide a strong argument for neurosurgical fenestration of temporal arachnoid cysts in children.

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.

Global trends and decision-making in the management of arachnoid cysts

OBJECTIVE

In pediatric patients, middle cranial fossa (MCF) arachnoid cysts are often discovered incidentally on imaging in asymptomatic patients during workup for other indications. This study aims to describe current management gestalt and threshold for surgical intervention by surveying an international cohort of neurosurgeons.

METHODS

A web-based survey was circulated via email list of attendants of the 2019 Canadian Pediatric Neurosurgery Study Group (CPNSG) and International Society of Pediatric Neurosurgery (ISPN) mailing list. The survey consisted of 8 clinical scenarios involving patients with MCF arachnoid cysts. Demographic variables of respondents and their decisions regarding management for each scenario were analyzed using R computing software.

RESULTS

A total of 107 respondents were included. Cysts in asymptomatic patients (92%), younger age at diagnosis (81%), and presence of a mild learning delay were predominantly managed non-surgically (80.7 ± 9.4%). Patients with cyst enlargement, headaches, new seizures, or hemorrhage were divided between non-surgical (55.8 ± 3.3%) and surgical (44.2 ± 2.9%) management. Patients with contralateral hemiparesis were treated predominantly surgically (67%). For both Galassi I and II, papilledema was favored as the primary indication for surgical intervention in 54% of patients. Those inclined to surgery (n = 17) were more likely to practice and train outside North America compared to those not pro-surgical (adjusted P = 0.092).

CONCLUSION

Incidental MCF arachnoid cysts in asymptomatic patients and younger age of diagnosis are predominantly managed non-surgically. Mild learning delay was not considered an indication to intervene. In contrast, radiological progression, hemorrhagic evolution, or non-focal neurological deficits lead to uncertainty in management, while focal neurological deficits and papilledema with MCF cysts were favored to be intervened surgically. Among the provider level factors, only location of training and practice trended towards a pro-surgery approach.

Evaluation of surgical treatment strategies and outcome for cerebral arachnoid cysts in children and adults

OBJECTIVE

The best treatment strategies for cerebral arachnoid cysts (CAC) are still up for debate. In this study, we present CAC management, outcome data, and risk factors for recurrence after surgical treatment, focusing on microscopic/endoscopic approaches as compared to minimally invasive stereotactic procedures in children and adults.

METHODS

In our single-institution retrospective database, we identified all patients treated surgically for newly diagnosed CAC between 2000 and 2022. Microscopic/endoscopic surgery (ME) aimed for safe cyst wall fenestration. Stereotactic implantation of an internal shunt catheter (STX) to drain CAC into the ventricles and/or cisterns was used as an alternative procedure in patients aged ≥ 3 years. Treatment decisions in favor of ME vs. STX were made by interdisciplinary consensus. The primary study endpoint was time to CAC recurrence (TTR). Secondary endpoints were outcome metrics including clinical symptoms and MR-morphological analyses. Data analysis included subdivision of the total cohort into three distinct age groups (AG1, < 6 years; AG2, 6-18 years; AG3, ≥ 18 years).

RESULTS

Sixty-two patients (median age 26.5 years, range 0-82 years) were analyzed. AG1 included 15, AG2 10, and AG3 37 patients, respectively. The main presenting symptoms were headache and vertigo. In AG1 hygromas, an increase in head circumference and thinning of cranial calvaria were most frequent. Thirty-five patients underwent ME and 27 STX, respectively; frequency did not differ between AGs. There were two (22.2%) periprocedural venous complications in infants (4- and 10-month-old) during an attempt at prepontine fenestration of a complex CAC, one with fatal outcome in a 10-month-old boy. Other complications included postoperative bleeding (2, 22.2%), CSF leaks (4, 44.4%), and meningitis (1, 11.1%). Overall, clinical improvement and significant volume reduction (p = 0.008) were seen in all other patients; this did not differ between AGs. Median follow-up for all patients was 25.4 months (range, 3.1-87.1 months). Recurrent cysts were seen in 16.1%, independent of surgical procedure used (p = 0.7). In cases of recurrence, TTR was 7.9 ± 12.7 months. Preoperative ventricular expansion (p = 0.03), paresis (p = 0.008), and age under 6 years (p = 0.03) were significant risk factors for CAC recurrence in multivariate analysis.

CONCLUSIONS

In patients suffering from CAC, both ME and STX can improve clinical symptoms at low procedural risk, with equal extent of CAC volume reduction. However, in infants and young children, CAC are more often associated with severe clinical symptoms, stereotactic procedures have limited use, and microsurgery in the posterior fossa may bear the risk of severe venous bleeding.

Improvement in Hearing Loss Following Posterior Fossa Arachnoid Cyst Fenestration: A Case Study

Arachnoid cysts are abnormal intradural collections of cerebrospinal fluid. For posterior fossa arachnoid cysts (PFACs), symptoms vary greatly, often relating to cranial nerve impingement and/or hydrocephalus. Literature on long-term symptomatic and radiographic follow-up of PFACs is lacking. This case study describes a 32-year-old man who presented with headaches and left-sided hearing loss and was found to have a large left-sided cerebellopontine angle arachnoid cyst with syrinx and ventriculomegaly. After PFAC fenestration and excision, his headaches resolved and his hearing markedly improved. At the one-year postoperative evaluation, symptom improvement persisted, and MRI demonstrated a stable decreased cyst and near-complete resolution of his syrinx.

Arachnoid cyst presenting as a neurosurgical emergency: a case report

Introduction

Arachnoid cysts are intra-arachnoid lesions filled with cerebrospinal fluid. They account for ~1% of all intracranial mass lesions and are non-neoplastic collections of cerebrospinal fluid within an anomalous arachnoid enclosure.

Case presentation

The authors report a 35-year-old Arabian male who presented to the ER with a history of sudden loss of consciousness, anisocoria, and right hemiparesis. Contrast tomography showed a large frontoparietotemporal cyst (7.7×5.8×5.4) with uncal herniation and a midline shift of 12 mm. An emergency left FTP craniotomy with an excision of the cyst was performed.

Discussion

Arachnoid cysts can be categorized as primary or secondary, arising congenitally or due to factors like trauma, infection, or neoplasia. It can rupture, leading to internal bleeding, causing symptoms such as headaches, seizures, and neurological decline. Rapid diagnosis is vital, with cranial computed tomography scans preferred for emergencies. Treatment options include surgical intervention like craniotomy, fenestration, or cyst peritoneal shunts. For uncal herniation, surgery can be successful and results depends on the amount of herniation.

Conclusion

Although benign, the arachnoid cysts led to uncal herniation when they become 'tension' cysts. A high level of suspicion is crucial for early recognition of the condition. Timely intervention has shown positive recovery outcomes.

An arachnoid cyst rupture complicated with subdural hygroma in a middle-aged woman: a case report and review of the literature

Background

Arachnoid cysts (ACs) account for about 1% of all intracranial mass lesions. The Sylvian fissure is the most common site of ACs which are usually asymptomatic. Traumatic rupture of arachnoid cysts complicated with subdural hygroma is a relatively rare entity in adults especially in females. There is no consensus on their management and each case could add to previous experiences leading to more uniform therapeutic measurements. This case encompasses a combination of watchful strategy, limited surgery and ultimately successful cyst fenestration which highlights a good outcome without complications by adopting a stepwise procedure.

Case presentation

Here, the case of a 51-year-old Persian woman being presented with a 2-month history of a localized headache which had begun 4 days after a minor head trauma. Early brain computed tomography (CT) obtained in another center at 4th day of post-injury which misinterpreted as an old infarct. Repeated CT in our center revealed a large AC of Sylvian fissure complicated with subdural hygroma. Initially a conservative management pursued but due to worsening of the symptoms, a burr-hole craniotomy performed for hygroma evacuation that subsequently followed by cyst fenestration about 1-month later.

Conclusion

Previous awareness about radiographic characteristics of ACs as well as employing appropriate imaging modality are necessary for correct and timely diagnosis of symptomatic patients after minor head trauma because incidentally found ACs might be the underpinning causes of symptoms. Also, following a multistage therapeutic process along with the involvement of patients in decision-making are of paramount importance.

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.

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.

A rare case of pediatric ptosis: Coexistence of giant intracranial arachnoid cyst and facial asymmetry

BACKGROUND

Intracranial arachnoid cysts are cystic congenital malformations, filled with cerebrospinal fluid (CSF) originating from the arachnoid membrane. Generally, giant arachnoid cysts present with symptoms related to increased intracranial pressure, hydrocephalus or cognitive disorders, endocrinological problems, growth retardation, seizures, headache, and nonspecific symptoms such as dizziness. They can be detected by imaging when they become symptomatic or incidentally in childhood and adulthood. Our case was referred to our clinic because of ptosis and facial asymmetry found on examination. Subsequently, a intracranial giant arachnoid cyst was found incidentally on cranial computed tomography (CT).

CASE

In an 18-month-old male infant admitted with ptosis, left frontal bulging and a dystopic globe with ptosis of the left upper lid were noted. The left half of the facial region and the left nostril also appeared to be asymmetrically elongated downward relative to the right. Fundus examination revealed an optic disc coloboma in the left eye. On general physical examination, he was unable to walk. A giant fronto-temporo-parietal arachnoid cyst with the cerebral parenchyma shifted 2cm to the right of the midline was observed on cranial CT. After a cysto-peritoneal shunt was performed, the physical appearance of our patient returned to normal.

CONCLUSION

Ptosis cases accompanied by abnormalities such as optic disc coloboma and facial asymmetry should be evaluated for possible midline defects and intracranial pathologies prior to eyelid surgery.

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.

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.

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.

Characteristic and management of pediatric arachnoid cysts: A case series

Background/Aim: Arachnoid cysts (ACs) are the collection of fluid, which is similar in composition to cerebrospinal fluid, within the congenitally duplicated arachnoid membrane. ACs are clinically silent lesions, but sometimes they can manifest themselves with headache, convulsion, focal neurological deficits, cognitive decline, torticollis, and macrocephaly. Although the appropriate surgical approach is less clear, there is a consensus on the need for surgical treatment in symptomatic ACs. This study aims to reveal the advantages and disadvantages of cystoperitoneal shunt and microsurgical fenestration techniques. Methods: One hundred ninety-one consecutive patients from 1 month to 15 years old with AC were evaluated for suitability. Sixteen patients who underwent surgery were included in the study. Medical records of the patients with AC managed at our institutions were retrospectively collected and analyzed. Sixteen of 191 patients underwent surgical treatment via craniotomy for microsurgical cyst fenestration (CF) and cysto-peritoneal shunting (CS). CF was performed with partial cyst wall excision in all patients. Results: Seizure was the most common presentation in the patients, followed by headache and trauma, respectively. In our series the most common indications of the surgery were increased intracranial pressure (IICP). CF was performed in nine patients, and CS was performed in seven as the primary treatment. CS-related complications, such as infection (n = 2), dysfunction (n = 2) and intraabdominal abscess (n = 1) were the most commonly observed complications. No infections were observed after CF, but subdural hematoma was observed in one child. Conclusions: Although the most common symptoms in cases with arachnoid cysts are headache, rare symptoms, such as torticollis, may exist. Due to this, clinicians should reveal the cyst-complaint relationship first. Given the increased complications of CS, in addition to shunt independency and being free from shunt-related complications, the microsurgical CF with wide excision of the membranes seems to be the more preferable surgical option.

Acetazolamide to treat symptomatic ruptured arachnoid cysts: illustrative cases

BACKGROUND

Arachnoid cysts are benign, often asymptomatic intracranial mass lesions that, when ruptured, may cause seizures, raised intracranial pressure, hemorrhage, and/or loss of consciousness. There is no widely agreed upon treatment, and there is debate as to whether a nonoperative or surgical approach is the best course of action. The carbonic anhydrase inhibitor acetazolamide may be an effective nonoperative approach in treating ruptured arachnoid cysts.

OBSERVATIONS

The Pediatric Neurosurgery Clinical Database at BC Children’s Hospital from 2000 to 2020 was queried, and four pediatric patients who were treated with acetazolamide after presentation with a ruptured middle cranial fossa arachnoid cyst were identified. All patients showed some degree of symptom improvement. Three of the patients showed complete reabsorption of their subdural collections in the ensuing 6 months. One patient had an inadequate response to acetazolamide and required surgical management.

LESSONS

Acetazolamide is a safe and reasonable primary treatment option in pediatric patients with ruptured middle cranial fossa arachnoid cysts, and it may help avoid the need for surgery.

Impaired visual acuity as an only symptom of shunt malfunction, long time after initial cyst-peritoneal shunting for arachnoid cyst: A case report

Background:

Long-term outcomes after surgical treatment of arachnoid cysts (ACs) have not been reported adequately. Impaired visual acuity is not a common symptom of shunt dependency syndrome due to cyst-peritoneal (CP) shunt malfunction for ACs. We report a case of CP shunt malfunction, who presented only impaired visual acuity as a symptom, long after the initial surgical treatment.

Case Description:

A 16-year-old boy was surgically treated for the left frontal AC with CP shunting at 2 years of age. Extension of the peritoneal shunt catheter was performed at 15 years of age. A year later, he started experiencing impairment of visual acuity without headaches, which worsened to bilateral light perception. The presence of bilateral optic atrophy was confirmed. The AC in the left frontal lobe had enlarged very slightly, with shortening of the intracystic catheter, and the cerebrospinal fluid pressure was elevated to 30 cmH2O. He was treated with lumboperitoneal shunting. The visual acuity showed limited improvement.

Conclusion:

The possibility of CP shunt malfunction and shunt dependency syndrome should be considered, even if the patient presented only impaired visual acuity and no significant changes in the size of the ACs are observed.

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) and Precocious Puberty With a Third Ventricle Arachnoid Cyst

Arachnoid cyst (AC) is a rare defect of the central nervous system that accounts for 1% of all intracranial lesions, of which only 1% of reported cases are located in the third ventricle. Endocrine manifestations associated with AC include precocious puberty, growth hormone deficiency, and hypothalamic dysfunction. We report a child who presented with a visual field defect, hyponatremia, and precocious puberty related to a third ventricle AC. Hyponatremia as a complication of AC is rare. A literature review revealed two case reports of Syndrome of inappropriate antidiuretic hormone secretion (SIADH) associated with suprasellar AC. The pathophysiology of SIADH in AC is not well understood. Hyponatremia may worsen following endoscopic fenestration of the AC secondary to changes in intracranial pressure. In conclusion, hyponatremia with AC should be recognized during the preoperative and postoperative periods and may require treatment with hypertonic saline in addition to fluid restriction.

A rare association between a dermoid cyst and arachnoid cyst of the cerebellopontine angle: a case report

Supratentorial arachnoid cysts are usually asymptomatic and may be discovered by chance at autopsy; however, infratentorial arachnoid cysts, which correspond to liquid forms enclosed by an arachnoid sheet but whose pathogenesis is unknown, might cause symptoms. They don't need to be treated if they're asymptomatic and were discovered by chance. A variety of neurological symptoms can be present depending on their localization. Intracranial dermoid cysts are uncommon tumours that develop from ectopic epithelial cells in the brain. They are benign, slow-growing, and rarely rupture. The association between the two diseases is extremely rare and when it is present may suggest the existence of a common factor. We present a unique case of a young girl who developed headache and ataxia as a result of an intracranial infratentorial dermoid cyst and an arachnoid cyst of the cerebellopontine angle. Complete removal of the dermoid cyst and drainage of the cyst leads to a full recovery. Dermoid and arachnoid cyst are two pathologies with a possible common embryogenic factor, early surgery can give a better outcome in the long term.

Arachnoid Cyst in Middle Cranial Fossa With Intraorbital Cyst (Orbital Meningocele)

Intracranial arachnoid cysts are extra-axial non-enhancing cerebrospinal fluid (CSF) density lesions. These are usually incidental findings on radiological investigations. Usually, the patients with arachnoid cysts are asymptomatic until the cyst grows large while symptomatic patients present with headaches, seizures, and focal neurological deficits. The adjacent calvarial bone may show remodeling and scalloping. Magnetic resonance imaging (MRI) stands superior in soft-tissue contrast and multiplanar imaging in excluding other lesions from the arachnoid cyst. Arachnoid cysts follow CSF signals in all pulse sequences with no gadolinium enhancement. Intraorbital extension of the intracranial arachnoid cyst (intraorbital meningocele) is rarely reported in the literature and occurs through the small bony defect. We report a case of a 20-year-old male presenting with proptosis who was detected to have an arachnoid cyst in the middle cranial fossa with intraorbital extension through a small bony defect in the lateral wall of orbit with the resultant orbital cyst.

[Endoscopic fenestration of arachnoid cyst of posterior cranial fossa through third ventriculostomy]

Arachnoid cysts (AC) are spaces with cerebrospinal fluid covered with arachnoid membrane. Most cysts are supratentorial and only 10-12% of ACs are found in posterior cranial fossa. This disease is usually diagnosed in childhood. In adults, ACs make up 1.4% of all focal lesions. ACs of posterior cranial fossa are often localized behind the cerebellum or in cerebellopontine angle. Most patients with cysts do not have permanent symptoms and should be followed-up. Surgery is indicated for cysts complicated by focal and hydrocephalic-hypertension symptoms. Microsurgical or endoscopic procedures are used. Surgical approach is determined by the closest location of cyst to brain surface. The authors report non-standard surgical approach for giant AC of posterior cranial fossa complicated by obstructive hydrocephalus, intracranial hypertension and visual function impairment. Endoscopic third ventriculostomy was followed by AC fenestration through ventriculostomy. Symptoms disappeared within 6 months after surgery.

Imaging of Sella and Parasellar Region

The sellar and parasellar region is complex, with a unique meningeal, neural, vascular, and bony anatomy. Understanding the imaging anatomy is critical for accurate imaging interpretation. resonance (MR) imaging is the primary modality for pituitary imaging, whereas computed tomography may be used when MR imaging is contraindicated, and provides complementary bony anatomic information. This article reviews embryology and anatomy of the sellar and parasellar region. Imaging appearances of pituitary adenomas, Rathke cleft cysts, meningiomas, craniopharyngiomas, arachnoid cysts, vascular disorders, infectious abnormalities, and pituitary apoplexy are discussed and illustrated.

The health-related quality of life in children with arachnoid cysts. Clinical predictors and parent-child perspectives

BACKGROUND

In clinical practice, arachnoid cysts are usually detected by coincidence and are frequently considered as clinically mute. Even though an AC does not usually result in serious symptoms, the diagnosis itself can have a significant impact on the patients and their families, especially in terms of psychological functioning and quality of life.

METHODS

Participants were 22 pairs of children diagnosed with AC and their parents. We analysed patients' medical records and assessed them using the Stanford Binet Intelligence Scale ed. 5th. Additionally, both children and parents filled in the Polish version of the PedsQL™ 4.0 generic core module.

RESULTS

The HRQOL is not related to objective predictors such as radiological predictors and SB 5 results. However, there is a correlation between the HRQOL, and symptoms given in the interview. Secondly, parents assess the HRQOL of their children worse compared to the children's own ratings. Lastly, children with AC assess the HRQOL in a way that is similar to the assessment done by healthy children in the original study describing PedsQL™, whereas parents assess children's HRQOL in a way rather similar to the assessment done by parents of patients.

CONCLUSIONS

The results show the impact of the disease's image and understanding on the HRQOL. Basing on our results we conclude the important role of psychological support for patients with AC. We furthermore conclude that parents of children with AC assess the HRQOL of children worse compared to the children's own ratings.

Surgical fenestration might not be the best option for very young patients with middle fossa arachnoid cysts

PURPOSE

Surgical fenestration is widely accepted as a primary treatment for middle fossa arachnoid cysts (MFACs) in pediatric patients. However, postoperative subdural effusion and/or hydrocephalus always affect treatment outcomes. In this study, we presented our experience of treating MFACs with surgical fenestration in pediatric patients and analyzed the cases complicated by postoperative subdural effusion and/or hydrocephalus, to give insight into the clinical characteristics predisposing the complications.

METHODS

We retrospectively analyzed 21 pediatric cases with MFACs treated by surgical fenestration suffering postoperative subdural effusion and/or hydrocephalus in our department from November 2011 to April 2019. We reviewed the clinical characteristics and treatment outcomes.

RESULTS

A total of 21 patients, among a total of 53 pediatric patients with MFACs treated by surgical fenestration, developed subdural effusion and/or hydrocephalus postoperatively. The mean age at the time of the initial surgery was 49 months. A total of 75% (6/8) of the patients under 2 years old and 13.3% (6/45) of the older patient group sustaining postoperative subdural effusion and/or hydrocephalus required further surgeries, respectively (Fisher's exact test, p = 0.001). Notably, among the 21 cases with postoperative subdural effusion and/or hydrocephalus, all the 6 patients under 2 years old needed additional surgeries, while of the other 15 older patients, only 40% (6/15) needed further surgical interventions (Fisher's exact test, p = 0.019).

CONCLUSION

The immature CSF absorption in MFAC patients younger than 2 years old might predispose them to the relatively serious postoperative subdural effusion and/or hydrocephalus. For very young patients with giant MFACs, surgical fenestration might not be the best option.

Results of Surgical Treatment in Patients with Intracranial Arachnoid Cyst During Last 5 Years in a Referral Center in a Developing Country: Shiraz, Iran

OBJECTIVE

To report the outcome of surgical intervention in patients diagnosed with arachnoid cyst (AC) during the last 5 years in Namazi Hospital, a tertiary center in Southern Iran.

METHODS

Hospitalization records of patients who had undergone surgical treatment of symptomatic intracranial AC in our center were surveyed retrospectively. Radiologic imaging was extracted from the picture archiving and communication system and analyzed. Postoperative evaluation of patients was conducted in neurosurgery clinic during their routine follow-up.

RESULTS

Twenty-nine patients (11 female, 18 male) with an age range of 13 days to 35 years were enrolled in this study. Most (62%) of all ACs were in the temporal area, 12% in the suprasellar region, 6% in the quadrigeminal region, 6% in the cerebellopontine angle, and 3% in the anterior frontal area. Twenty-six endoscopic intervention, 2 microsurgical resection, and 1 cystoperitoneal shunt were performed. All of the patients showed complete resolution or improvement in symptoms. Eighty-nine percent of patients also showed reduction in the cyst size. Ten patients had transient postoperative complications, which were resolved at the time of follow-up.

CONCLUSIONS

Diagnosis and appropriate surgical treatment of AC can alleviate the symptoms in patients who fulfill the criteria for surgery. Neuroendoscopy can provide a satisfactory result in symptomatic patients, whilst having less invasiveness and long-term complications. Reoperation should also be considered in situations where medical therapy fails to manage the complications.

Objective improvement in adults with cerebellopontine angle arachnoid cysts after surgical treatment

BACKGROUND

Intracranial arachnoid cysts are extra-axial benign lesions mainly found in the middle cerebral fossa. Rare case series report various cranial nerve dysfunctions associated with cerebellopontine angle (CPA) cysts and there is no consensus with regard to their surgical management; some reports claiming that subjective improvement in adults with intracranial arachnoid cysts cannot justify surgical treatment.

METHODS

This retrospective study included all 12 consecutive adult patients treated by microsurgical fenestration for symptomatic CPA arachnoid cysts between 2010 and 2019 and using a retrosigmoid approach. Demographic, clinical, surgical, and radiological data were collected from medical files.

RESULTS

The main symptoms were audiovestibular in 9 patients (75%) complaining of dizziness and 6 patients (50%) with hearing loss. In addition, 3 patients (25%) reported tinnitus, 3 patients (25%) presented vasovagal syncope, and 1 patient (8.3%) reported facial pain. Surgery improved 5 patients (83%) with pre-operative hearing loss, 7 patients (78%) reporting dizziness, and all patients with vasovagal syncope. All of the patients recovered from at least one symptom. No recurrence was observed with a mean follow-up of 5.5 years.

CONCLUSION

Although most arachnoid cysts are asymptomatic, the CPA location may lead to cranial nerve impairments. Microsurgical fenestration seems to be a simple, safe, and effective technique.

Paediatric arachnoid cysts: Surgical outcomes from a Singapore children's hospital

Arachnoid cysts (AC) are reported to have a prevalence of up to 2.6% in children. Most AC remain indolent, but others may expand or rupture to cause life-threatening symptoms of raised intracranial pressure. Currently, there are 2 controversial topics with regards to the management of ACs: the indications for surgery and the choice of surgical procedure. We therein report our institution's neurosurgical experience for symptomatic AC over a 22-year period and corroborate our results with published literature. This is a single institution, retrospective study conducted at KK Women's and Children's Hospital from 01 January 1998 to 31 December 2019. A total of 38 patients with ACs that required surgery were recruited. The 3 most common anatomical locations were in the middle cranial fossa (40.5%), posterior fossa (24.3%) and interhemispheric (13.5%). Typical clinical presentations included symptoms of raised intracranial pressure (34.2%), obstructive hydrocephalus (28.9%) and AC rupture (21.1%). Surgical approaches included 17 craniotomy-based procedures, 7 endoscopic fenestrations, 11 cystoperitoneal shunts, 2 burrhole drainage operations and 1 excision of spinal AC. Thirteen patients (34.2%) underwent either another operation due to the lack of resolution of their AC-related symptoms or secondary to complications directly related to their initial surgery. Average length of followup from time of first operation was 84.1 months. Overall, our results demonstrate similarities in epidemiology, clinical presentation and surgical experience, in comparison to larger cohort studies. We advocate collaborative efforts to better understanding of the pathophysiology of paediatric ACs, particularly for deciding between the various surgical treatment modalities.

Giant Arachnoid Cyst Associated with an Orbital Meningocele: A Case Report and Cystoperitoneal Shunt Management

INTRODUCTION

Intracranial arachnoid cysts (ACs) are space-occupying lesions that typically remain stable in size and clinically silent over time.

CASE REPORT

We describe an unusual pediatric case of enlarged AC impressive by its compressive phenomena. An 11-month-old girl presented with remarkable macrocephaly associated with a cystic orbital tumor. CT scan and MRI studies revealed a large intracranial ACs extending in the orbit with an orbital meningocele (OM). The intracranial cyst did communicate with the orbital one into a bony defect in the right inner region of the orbital roof and represses the globe outward. A cystoperitoneal shunting procedure was performed to remove the mass effect as soon as possible and facilitate normal development.

DISCUSSION/CONCLUSION

Cysts in infants younger than 1 year of age are remarkably different from those in older children and adults in terms of cyst localization and enlargement. Classically described complications result from compression of adjacent structures and include focal neurologic involvement, headaches and seizures and developmental deficits, or macrocephaly in younger children. There are few cases of ACs with ophthalmic manifestations reported in the literature. The paucity of literature prompted us to analyze the case. To the best of our knowledge, an AC accompanying OM has not been reported. The pathogenesis and management of the case will be discussed.

A large interhemispheric glioependymal cyst associated with partial defect of the corpus callosum in an elderly man

Interhemispheric cysts are congenital, and usually present symptoms during childhood. However, they are occasionally detected in adults. These cystic lesions are sometimes associated with defects of the corpus callosum. Although defects of the corpus callosum by themselves do not present clinical symptoms, they are often accompanied by other brain malformations. A man in his late 60s was found dead at the scene of a fire. At autopsy, his brain weighed 1223 g and had a large interhemispheric cyst, measuring 5.5 × 4.5 × 4.0 cm in size. The cyst contained clear fluid but was not connected to the ventricular system. On slices of the cerebrum, the corpus callosum did not connect the right and left cerebral hemispheres, and the right lateral ventricle was dilated. By the existence of the cyst, compressed by the cyst, the hemispheres were displaced on either side. Histologically, the cerebral parenchyma around the cyst was slightly edematous but structurally normal. Immunohistochemically, both glial fibrillary acidic protein and podoplanin were expressed in the cystic components. Thus, the cystic lesion was diagnosed as a glioependymal cyst. In this case, because the cyst was located at the interhemispheric space between the right and left frontal lobes, the individual experienced no obvious symptoms, despite its large size. The individual's brain malformations included the partial defect of the corpus callosum and the cyst. The dilation of the right lateral ventricle was considered to result from the location of the cyst. Under the influence of the cyst, the third ventricle was displaced downward, and one or both of the interventricular foramen were obstructed. The decedent had burns over his whole body. Burns to the epiglottis and soot in the airway were also observed. Volatile hydrocarbons, such as benzene and styrene, were detected in the blood. The percentage of carboxyhemoglobin levels in a total of hemoglobin levels were 19-25%. Therefore, the individual's cause of death was established as death by fire.

Bilateral Retrocerebellar Arachnoid Cysts Presenting as Peripheral Vertigo: Case Report and Literature Review

Bilateral retrocerebellar arachnoid cysts are exceedingly rare. We report a case of a 38-year-old woman, who presented with progressive vertigo and was found to have bilateral retrocerebellar arachnoid cysts. The patient’s clinical presentation was most consistent with benign positional peripheral vertigo, while the cysts were thought to be incidental findings. We review the literature on bilateral retrocerebellar arachnoid cysts and discuss their management.

Prenatal diagnosis of arachnoid cysts: a case series and systematic review

INTRODUCTION

Primary cysts are believed to arise from the splitting of the arachnoid membrane during prenatal development and can be diagnosed in utero. Prenatal diagnosis is uncommon; therefore, the evidence base for counselling expectant mothers is limited. The purpose of this article is to present a case series and review the current literature on prenatally diagnosed arachnoid cysts.

METHOD

A keyword search of hospital electronic records was performed for all patients with a prenatally diagnosed arachnoid cyst at a tertiary neurosurgical centre. Case notes were reviewed for all patients diagnosed between 2005 and 2017. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to structure a systematic review of all English language articles published up to May 2018.

RESULTS

A total of eight eligible patients were identified from our own records and 123 from the literature. Sixty-eight per cent of patients had a normal outcome. Sixty-three per cent of patients underwent surgical intervention which was not associated with abnormal outcome. The diagnosis of syndromic/genetic diagnosis (p < 0.001) and the presence of other intra-cranial anatomical abnormalities (p = 0.05) were significant predictors of abnormal outcome.

CONCLUSION

The pathogenesis and prognosis of a prenatal arachnoid cyst diagnosis remain unclear. These results suggest favourable outcomes from simple cysts without associated abnormalities and expectant mothers should be counselled accordingly. A wider prospective review is required to better established evidence-based practice.

Sporadic Meningioangiomatosis Presenting as a Middle Cranial Fossa Arachnoid Cyst

BACKGROUND

Meningioangiomatosis is an extremely rare meningovascular disease of the central nervous system that is characterized by the proliferation of leptomeninges, cortical vessels, and perivascular spindled cells. Although it is a benign, neoplastic disorder that carries a good prognosis after surgical excision, initial diagnosis may be challenging as radiologic findings are often variable and nonspecific.

CASE DESCRIPTION

In this report, we describe an unusual presentation of meningioangiomatosis presenting as a symptomatic middle cranial fossa arachnoid cyst.

CONCLUSIONS

In view of the unexpected diagnosis and infrequency of this condition, the case is discussed in collaboration with current literature and management strategies.

Disappearance of Arachnoid Cyst after Burrhole Trephination: Case Series

We report 3 cases of arachnoid cysts (ACs) that completely disappeared after burr hole drainage, without cyst fenestration into the subarachnoid space or cystoperitoneal shunt. The first patient was a 21-year-old female with an AC of the right cerebral convexity, found incidentally. After endoscopic AC fenestration was performed, the patient complained of persistent headache. Two-month postoperative brain imaging revealed reaccumulated AC and associated multi-stage subdural hematoma. Burr hole drainage was performed to resolve the chronic subdural hematoma (CSDH). Three months later, brain computed tomography showed that the CSDH and the AC had disappeared. The second patient was an 11-year-old male who had a history of trauma 1 month prior to presentation at the clinic. Brain magnetic resonance imaging revealed an AC in the left sylvian fissure with CSDH. We performed burr hole drainage to treat the CSDH first. Subsequently, the AC as well as the CSDH disappeared. The third case was an AC of the right parietal convexity, found incidentally. Only burr hole drainage was performed, following which, the AC disappeared. This case series shows that an AC can disappear naturally after rupture into the subdural space by trauma or the burr hole procedure.

Intraparenchymal supratentorial arachnoid cyst: a case report

Background

Intracranial arachnoid cysts are collections of cerebrospinal fluid within the arachnoid membrane and subarachnoid space of the cisterns and major cerebral fissures that account for about 1% of all intracranial lesions. Expansion of the cyst and compression on surrounding structures may became symptomatic, which reflects its size and anatomic distribution.

Case presentation

Here, we present a very rare case of patient with supratentorial intraparenchymal arachnoid cyst placed in the left frontal lobe without any communication with the subarachnoid space and ventricle and presented with clinical symptoms. The patient underwent fenestration of the lesion and was clinically improved.

Conclusions

Although the etiology and the enlargement mechanism of arachnoid cysts remain unclear, both conservative and surgical treatments are optional. According to size, anatomical location, neuroimaging, and clinical symptoms, an arachnoid cyst should be included in the differential diagnosis of primary intracerebral cysts.

When the brain looks imperfect: An example of neuroplasticity as seen in a patient with arachnoid cysts - a case study

Objective: This study presents a case of a teenager (J.J.) prenatally diagnosed with large arachnoid cysts which did not allow parts of his brain to develop correctly. It aims to establish whether the congenital malformation affected the boy's cognitive development.Method: In order to assess his cognitive development, the authors analyzed J.J.'s medical history, interviewed him and his parents and conducted neuropsychological examination.Results: Despite major parts of his brain undeveloped, the boy achieved average to outstanding scores in all tests.Conclusions: The scores achieved by J.J. suggest that normal development of cognitive abilities is possible even for a person whose central nervous system differs structurally from what is expected in a healthy subject.

Management of Neonatal Facial Paralysis due to Cerebellopontine Angle Arachnoid Cyst: A Case Report

Arachnoid cysts are benign, cerebrospinal fluid-filled collections that can be located in the brain or spinal cord. Arachnoid cysts form approximately 1% of all intracranial lesions. They are accepted as arachnoid developmental anomaly and arise from membrane splitting or duplication. Generally, lesion growth causes symptoms because of mass effect or obstruction. Arachnoid cyst growing mechanisms are a largely controversial issue. We report the case of a neonatal female patient who presented with congenital facial paralysis. Magnetic resonance imaging showed a right cerebellopontine angle arachnoid cyst causing severe mass effect on the brain stem. Cyst fenestration and cystocisternal shunt was performed through retrosigmoid suboccipital craniotomy.

Glimpse into Pathophysiology of Sellar Arachnoid Cysts

BACKGROUND

Sellar arachnoid cysts are a rare occurrence but may impinge on vital parasellar anatomy and thus are often symptomatic. The etiology of sellar arachnoid cysts is contentious, fueled by heterogeneity in cyst wall structure and contents between cases. The "ball-valve" mechanism is 1 of 2 predominant theories describing their formation, which contends that an aperture in the diaphragm allows cerebrospinal fluid to enter the cyst, propelled by pulsatile flow, but its egress is obscured by the pituitary during the ebb of the pressure wave.

CASE DESCRIPTION

Here we present a case of a 51-year-old female with a symptomatic sellar arachnoid cyst. She underwent an endoscopic transsphenoidal fenestration which alleviated her symptoms.

CONCLUSIONS

Intraoperative video evidence during arachnoid cyst fenestration supports the "ball-valve" theory of sellar arachnoid cyst development.

Neuroendoscopic treatment of multiple intracranial arachnoid cysts: a case report

Background

Multiple arachnoid cysts are very rare within the central nervous system. The cysts will sometimes increase in size with age, lead to the mass effect or cerebrospinal fluid (CSF) flow obstruction, and cause some symptoms, which requires the surgery intervention.

Case presentation

A 35-year-old female was admitted to our hospital with some symptoms related to hydrocephalus for 1 month. Brain magnetic resonance imaging (MRI) revealed well-marginated cystic lesions with CSF signal intensity in the ventricular and cisternal systems, bilateral temporal lobes, and left occipital lobe. Cine phase-contrast MRI showed the aqueduct of sylvius was blocked by the cyst in the quadrigeminal cistern. We employed endoscopic ventriculocystostomy and septostomy to create the communication of the cyst with ventricular and cistern system. As a result, the patient's symptoms were relieved.

Conclusions

Endoscopic management can be an effective way for treating intracranial multiple arachnoid cysts, which is the first report of this kind. We hope that this report could help improve the management of intracranial arachnoid cysts with the neuroendoscopic technology.

Rare Case of Convexity Meningioma Growing into Arachnoid Cyst

BACKGROUND

Meningioma growing into an arachnoid cyst is an extremely rare event. Only 3 cases are reported in the literature. In 2 of them, an operative procedure in or near the arachnoid cyst preceded tumor growth.

CASE DESCRIPTION

We report a case of a patient requiring marsupialization of an arachnoid cyst of the middle cranial fossa. On follow-up, 3 years postoperatively he showed no signs of recurrence or tumor growth. One year later, the fourth year after surgery on the cyst, he presented with large tumor growth into the former cyst's cavity. Pathologic workup after resection revealed an atypical meningioma (World Health Organization grade II).

CONCLUSIONS

We discuss the possible pathogenesis in light of the scarce published literature, as well as the differential diagnosis of this rapidly growing tumor.

Rare case of a rapidly enlarging symptomatic arachnoid cyst of the posterior fossa in an infant: A case report and review of the literature

Background:

Intracranial arachnoid cysts are space-occupying lesions that typically remain stable or decrease in size over time. Cysts in infants younger than 1 year of age are remarkably different from those in older children and adults in terms of cyst localization and enlargement. Arachnoid cysts of the posterior fossa (PFACs) are very rare in infants and do not typically grow or present with clinical symptoms, such that surgical treatment is generally considered to be unnecessary. Here, we describe an extremely rare case of an infant with a rapidly enlarging symptomatic PFAC that was successfully treated with surgery.

Case Description:

A 4-month-old boy presented with increasing head circumference and a rapidly enlarging arachnoid cyst in the left posterior fossa with ventriculomegaly, which was documented using serial imaging over the preceding 2 months. We performed a microscopic resection of the cyst membrane to remove the mass effect as soon as possible and facilitate normal development. To confirm dural closure and prevent cerebrospinal fluid leakage, we also performed short-term (7 days) percutaneous long-tunneled external ventricle drainage after the surgery. Magnetic resonance imaging over a 4-year follow-up period revealed adequate reduction of the ventricle and cyst. The patient no longer exhibited progressive macrocrania and showed normal development.

Conclusion:

To our knowledge, this is the second successful case of surgical treatment of an enlarging symptomatic PFAC in an infant. Our surgical strategy for the treatment of this rare case can serve as a guide for surgeons in similar future cases.

Endoscopic surgery for intraventricular arachnoid cysts in children: clinical presentation, radiological features, management, and outcomes over a 12-year period

PURPOSE

Less than 0.5% of arachnoid cysts are intraventricular in origin. We review our experience with endoscopic surgery for intraventricular arachnoid cysts in children.

METHODS

This is a retrospective review of children with intraventricular arachnoid cysts who underwent surgery between 2005 and 2016. Clinical notes and imaging were reviewed.

RESULTS

Twenty-nine patients with endoscopically treated intraventricular arachnoid cysts were identified (M/F = 17:12; median age = 1.47 years, range = 7 days-13 years). All had hydrocephalus at presentation, many had symptoms/signs of raised intracranial pressure, and five (17%) were asymptomatic. Cysts were treated with fenestration into the ventricle alone (ventriculocystostomy [VC], n = 14), fenestration into the ventricle and cisternostomy (ventriculocystostomy plus cisternostomy [VC + C], n = 14), or endoscopic third ventriculostomy alone (n = 1). Six (21%) patients experienced transient and/or conservatively managed complications. Further surgery was required in 12 (41%). Revision-free survival was significantly shorter with VC compared to VC + C (log rank p = 0.049), and the majority of VC/VC + C revisions (n = 8 of 11, 73%) were required within 6 months of initial endoscopic surgery. One (3%) patient died during follow-up, from unrelated pathology. After a median follow-up of 67.5 months in survivors (range = 5.5-133.5 months), 24 (83%) cases were clinically and radiologically stable without a shunt in situ.

CONCLUSIONS

Endoscopic fenestration is safe and effective in most intraventricular arachnoid cysts. Additional cisternostomy at the time of cyst fenestration into the ventricle significantly improved revision-free survival in our cohort. Endoscopic surgery should be the first-line therapy when considering intervention for symptomatic intraventricular arachnoid cysts and for asymptomatic cysts increasing in size on serial imaging.

Primary Obstruction of the Foramen of Luschka: Anatomy, Histology, and Clinical Significance

BACKGROUND

The foramen of Luschka is a natural aperture between the fourth ventricle and the subarachnoid space at the cerebellopontine angle. Membranous closure of this foramen is referred to as primary obstruction. Available information about this variant and its role in the development of the cysts of the posterior fossa is contradictory.

METHODS

The macroscopic and histologic features of the obstructed foramina were examined in 61 formalin-fixed human brains (122 foramina). Three rhomboid lips of various sizes with lateral recess were used for comparison. Five postoperative cases of diverticulum of the foramen of Luschka were included in this study, with 1 case presented in detail to illustrate anatomic and histologic findings.

RESULTS

Primary obstruction was present in 11 of 122 cases. In 1 case, an enlarged rigid pouch with a thick wall was found. The wall of the membrane in primary obstruction and the rhomboid lip were composed of an inner ependymal, a middle glial, and an outer leptomeningeal layer.

CONCLUSIONS

The rhomboid lip is a remnant of the roof of the fourth ventricle. Imperforation of the foramen of Luschka results in a pouch in the cerebellopontine angle that contains choroid plexus (Bochdalek's flower basket) and communicates with the fourth ventricle. This pouch has the potential to grow to a diverticulum and cause clinical symptoms. Based on our clinical observations, detailed radiologic and surgical-anatomic criteria were proposed to support the differential diagnosis of a diverticulum of the foramen of Luschka. Treatment strategies were also suggested.

Posterior fossa arachnoid cyst causing torticollis and gastro-oesophageal reflux in an infant

INTRODUCTION

Arachnoid cysts (ACs) account for a small proportion of all intracranial lesions. They are often incidental but can become symptomatic and even cause a threat to life. Symptoms are usually due to direct compression of neural elements and/or raised intracranial pressure.

CASE REPORT

We report the case of an infant with an enlarging posterior fossa arachnoid cyst (PFAC) causing torticollis and gastro-oesophageal reflux (GOR), the combination of which had been previously unreported in this context. Endoscopic fenestration and cyst decompression were followed by complete resolution of the symptoms. We discuss the possible mechanisms of torticollis and GOR in this context.

Intracranial extradural arachnoid cyst in a child

INTRODUCTION

Arachnoid cysts are benign developmental anomalies of arachnoid membrane origin that can occur anywhere along the neuro-axis. They are believed to develop from the splitting or duplication of the arachnoid membrane by CSF that is trapped by a ball-valve mechanism. Intracranial arachnoid cysts have only been described as intradural lesions while spinal arachnoid cysts can be both intradural or extradural.

CASE REPORT

After an extensive literature review, we report the first case of an intracranial, extradural arachnoid cyst in a 5-yearold girl. The child presented with a 2-week history of suspected seizure-like activity and imaging revealed a large midline extradural CSF-containing arachnoid cyst causing severe compression of the superior sagittal sinus and underlying brain. Venous flow through the sagittal sinus was nearly obliterated. Osseous changes and bone growth adjacent to the cyst was also noted on imaging and intraoperatively. She underwent a bifrontal craniotomy and cyst excision with decompression of underlying brain and reestablishment of venous flow through the sagittal sinus.