Prevalence and natural history of arachnoid cysts in children

Intracranial arachnoid cysts: Pediatric neurosurgery update

Background:

With the greater worldwide availability of neuroimaging, more intracranial arachnoid cysts (IACs) are being found in all age groups. A subset of these lesions become symptomatic and requires neurosurgical management. The clinical presentations of IACs vary from asymptomatic to extremely symptomatic. Here, we reviewed the clinical presentation and treatment considerations for pediatric IACs.

Case Description:

Here, we presented three cases of IAC, focusing on different clinical and treatment considerations.

Conclusion:

IACs can be challenging to manage. There is no Class I Evidence to guide how these should be treated. We suggest clinical decision-making framework as to how to treat IACs based on our understanding of the natural history, risks/benefits of treatments, and outcomes in the future, require better patient selection for the surgical management of IACs will be warranted.

Is arachnoid cyst a static disease? A case report and literature review

INTRODUCTION

The increasing use of intracranial imaging has led to more frequent diagnoses of arachnoid cysts (ACs). Although ACs are a frequent finding on neuroimaging in children, the prevalence and natural history of these cysts are not well defined. Most ACs may persist and remain asymptomatic throughout life and not require treatment. However, there have been some case reports of ACs that have become larger or smaller over time and, in rare cases, have even spontaneously resolved. It is the authors' practice to recommend serial neuroimaging in patients with asymptomatic sylvian ACs and not offer surgery to patients without symptoms, even in those with a relatively large cyst.

CASE REPORT

The present article describes a case involving a 6-year-old boy with a large, asymptomatic AC in the left Sylvian fissure involving the temporo-frontal region, which resolved spontaneously during the 2-year follow-up period after initial diagnosis without any surgical intervention. Currently, at the 7-year follow-up, the patient has remained neurologically intact, attends school, and is symptom-free.

CONCLUSION

Clinicians should be mindful of the possibility of spontaneous regression when encountering patients with asymptomatic and/or incidentally diagnosed sylvian ACs.

Intracerebral hematoma after endoscopic fenestration of an arachnoid cyst: A case report

RATIONALE

An intracranial arachnoid cyst is a relatively common congenital benign lesion. A small number of patients present with neurological symptoms. Endoscopic fenestration has become a common treatment for arachnoid cysts in recent years, but intracerebral hematoma after surgery is rarely reported.

PATIENT CONCERNS

A 60-year-old woman with an arachnoid cyst in the left parietal and occipital lobes showed obvious progressive neurological deficits. She had weakness in her right limbs for 2 years and a sudden convulsion in her left limbs.

DIAGNOSIS

An arachnoid cyst in the left parietal and occipital lobes was detected on magnetic resonance imaging.

INTERVENTION

Endoscopic fenestration was performed for the cyst. However, she developed an intracerebral hematoma after surgery, which was detected by computed tomography. Due to the exacerbation of the patient's condition in the early stage after surgery, reoperation was performed to remove the hematoma.

OUTCOMES

The patient was finally cured with no serious neurological deficits.

LESSONS

The rare complication of intracerebral hematoma after surgery for an arachnoid cyst can lead to a rapid deterioration in the patient's condition. More-adequate preoperative examination and neuronavigation should be conducted during surgery. Appropriate enlargement of the bone hole may help protect against this complication. Moreover, prompt reoperation for the intracerebral hematoma may improve the prognosis.

Retroclival Arachnoid Cysts: Case Series, Literature Review, and New Classification Proposal

BACKGROUND

The retroclival region is among the rarest locations for an arachnoid cyst (AC), with only a few reported cases. No accepted classification system is available for these rare cysts. Such a classification system would solve the nomenclature problem and could result in easier and more systematic management. We reviewed and analyzed data from databases and reported studies of retroclival ACs (RACs) and have proposed a classification system.

METHODS

A retrospective review of RACs was conducted in Marmara and Adiyaman University Hospitals, Turkey. Cysts in the prepontine and/or premedullary cisterns that spared the chiasmatic cistern were included. Additionally, the reported data were searched for relevant studies on cysts. The findings were analyzed to establish a clear nomenclature and classification system, and the clinical presentations, treatment strategies, and surgical approaches were reviewed.

RESULTS

We identified 1 adult and 1 pediatric patient, and only the adult had undergone surgery. Additional data searches yielded 14 patients with RACs. The cysts were classified as type 1 if they had extended superiorly beyond the borders of the diencephalic leaf of the Liliequist membrane. If they had not extended, they were classified as type 2. Finally, type 2 cysts that had extended to the anterior spinal cistern were classified as type 3.

CONCLUSIONS

RACs can be more easily and systematically managed using a simple clinical classification system. Together with the previously proposed suprasellar AC classification, our proposed RAC classification should be adequate to classify all ACs in the ventral midline cistern, which could solve the nomenclature problem.

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.

Neurodevelopmental outcomes in children with large temporal arachnoid cysts

OBJECTIVE Management of children with large temporal arachnoid cysts (TACs) remains controversial, with limited data available on their neurodevelopmental outcome. The aim of this study was to examine neurodevelopmental outcomes in children with large TACs. METHODS In this medical center-based cohort study, 25 patients (19 males) who were diagnosed in childhood with large TACs (9 patients [36%] with a Galassi type II and 16 patients [64%] with a Galassi type III TAC) were examined. The mean ± SD age at assessment was 11.1 ± 5.6 years (range 2.7-22 years). Twelve patients (48%) had right-sided, 12 (48%) had left-sided, and 1 (4%) had bilateral cysts. Nine patients (36%) underwent surgery for the cyst. The siblings of 21 patients (84%) served as control participants. Neurodevelopmental function was assessed using the Adaptive Behavior Assessment System (ABAS), Vanderbilt Behavioral Rating Scale (VBRS), and Developmental Coordination Disorder Questionnaire (DCDQ), and quality of life was measured using the treatment-oriented screening questionnaire (TOSQ). The results of all instruments except for TOSQ were compared with those of the sibling control participants. RESULTS The mean ± SD ABAS score of the patients was 93.3 ± 20.09 compared with 98.3 ± 18.04 of the sibling control participants (p = 0.251). Regarding the incidence of poor outcome (ABAS score < 80), there was a trend for more patients with TAC to have poor outcome than the sibling controls (p = 0.058). Patients who underwent surgery scored significantly worse with regard to the VBRS total score compared with those who did not (p = 0.020), but not on ABAS, DCD, or TOSQ. The mean score of the cognitive and psychological items on TOSQ was lower than that for the physical items (p < 0.001). CONCLUSIONS Children with a large TAC performed similarly to their sibling control participants in neurodevelopmental function. However, a subgroup of those with cysts did have an increased risk for poor outcomes in general function. Neurodevelopmental assessment should be part of the management of all patients with TAC.

Management of Arachnoid Cysts: A Comprehensive Review

Arachnoid cysts are non-neoplastic, intracranial cerebrospinal fluid (CSF)-filled spaces lined with arachnoid membranes. Large arachnoid cysts are often symptomatic because they compress surrounding structures; therefore, they must be treated surgically. As several surgical management options exist, we explore the best approach according to each major type of arachnoid cyst: middle cranial fossa cyst, suprasellar cyst, intrahemispheric cyst, and quadrigeminal cyst.

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.

Nontraumatic Subdural Hematoma and Intracystic Hemorrhage Associated with a Middle Fossa Arachnoid Cyst

Intracranial arachnoid cysts (ACs) are relatively common findings that can be seen in up to 2% of patients. They are generally found incidentally with a benign clinical course and can be usually managed by observation. We report an unusual case of a middle fossa AC presenting with spontaneous intracystic hemorrhage along with subdural hematoma (SDH) causing significant mass effect and midline shift requiring surgical treatment. Even though the risk of hemorrhage in patients with AC is very low, the presence of AC is a known risk factor for SDH. Fortunately, the clinical outcome of patients who present with hemorrhage associated with AC is generally favorable with early recognition and prompt surgical treatment. Our case highlights the fact that both intracystic hemorrhage and SDH can occur in association with AC even in the absence of trauma and should be kept in mind when counseling patients with incidental AC about the natural history of these lesions.

Simultaneous bone remodeling and surgical decompression of large Sylvian arachnoid cyst

The most common location for intracranial arachnoid cysts is the region of the Sylvian fissure, where they can be found in 49% of cases. Management of these cysts is still quite controversial. We present our surgical technique for the treatment of large Sylvian fissure arachnoid cysts which involves cyst decompression and simultaneous calvarial remodeling. After decreasing cyst size, remodeling of the frontal, temporal, and parietal bones follows. The cyst itself is treated with a cystoperitoneal shunt. In immediate postoperative period, correction of the deformity is observed. The cyst volume is reduced immediately after surgery, and adequate adaptation of the bone is achieved. Our surgical procedure for simultaneous bone remodeling and cyst decompression is a fast, simple, and effective treatment option for patients with large Sylvian fissure arachnoid cysts associated with significant cranial disfigurement. We consider cranial remodeling in case of large arachnoid cyst important not just because of the cosmetic result but also for reducing remaining intracranial space filled with cerebrospinal fluid. It may be an important factor to reduce the risk of intracystic and subdural hemorrhage. It is a widely applicable procedure that does not require special tools and expensive equipment, and yet it can help avoid multiple surgeries and complications tied to them.

Sonographic diagnosis and prognosis of fetal arachnoid cysts

PURPOSE

To explore the clinical significance of sonographic (US) diagnosis of fetal arachnoid cysts and to evaluate their prognosis.

METHODS

Sixty fetuses deemed to have arachnoid cysts by prenatal US were included in this study. Data from serial US, prenatal and/or postnatal MRI, or post-mortem examinations were retrospectively analyzed. For live births, the developmental quotient scores were determined using the Gesell Developmental Scale.

RESULTS

Thirty fetuses were diagnosed during the second trimester and another 30 fetuses were diagnosed in the third trimester. Fifty-one lesions were located in the supratentorial compartment, and 9 were located in the posterior fossa. Twenty-four lesions were isolated, and the remaining lesions were associated with intracranial and/or extra central nervous system malformations. The evolution of the cysts included progression, stability, or spontaneous resolution. The outcomes included induced abortion, intrauterine death, live birth with either normal neurodevelopment or mental retardation, and infant mortality. Two cases were lost to follow-up. The accuracy of prenatal US diagnosis was 86.2% (50/58).

CONCLUSION

Prenatal US is the modality of choice for the diagnosis of fetal arachnoid cysts. Serial US examinations are critical to monitor the lesions. Moreover, prenatal MRI is a valuable complementary tool. For live births, the prognosis appears to be good.

Temporal arachnoid cysts: are they congenital?

CASE REPORT

The authors report two cases of arachnoid cysts (ACs) neither detected during pregnancy nor shortly after birth when newborns underwent CT scan evaluation after birth head trauma. ACs were diagnosed at 10 months and 6 years, respectively. The first one becomes symptomatic, and the other one was incidentally found during a head trauma investigation.

DISCUSSION

These cases give support for the postnatal pathogenesis for some of the assumed congenital ACs. We collected data from the literature that supports the acquired hypothesis for ACs.

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.

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.

Does subjective improvement in adults with intracranial arachnoid cysts justify surgical treatment?

OBJECTIVE

Subjective improvement of patients who have undergone surgery for intracranial arachnoid cysts has justified surgical treatment. The current study aimed to evaluate the outcome of surgical treatment for arachnoid cysts using standardized interviews and assessments of neuropsychological function and balance. The relationship between arachnoid cyst location, postoperative improvement, and arachnoid cyst volume was also examined.

METHODS

The authors performed a prospective, population-based study. One hundred nine patients underwent neurological, neuropsychological, and physiotherapeutic examinations. The arachnoid cysts were considered symptomatic in 75 patients, 53 of whom agreed to undergo surgery. In 32 patients, results of the differential diagnosis revealed that the symptoms were due to a different underlying condition and were unrelated to an arachnoid cyst. Neuropsychological testing included target reaction time, Grooved Pegboard, Rey Auditory Verbal Learning, Rey Osterrieth complex figure, and Stroop tests. Balance tests included the extended Falls Efficacy Scale, Romberg, and sharpened Romberg with open and closed eyes. The tests were repeated 5 months postoperatively. Cyst volume was pre- and postoperatively measured using OsiriX software.

RESULTS

Patients who underwent surgery did not have results on balance and neuropsychological tests that were different from patients who declined or had symptoms unrelated to the arachnoid cyst. Patients with a temporal arachnoid cyst performed within the normal range on the neuropsychological tests. Seventy-seven percent of the patients who underwent surgery reported improvement, yet there were no differences in test results before and after surgery. Arachnoid cysts in the temporal region and posterior fossa did not influence the preoperative results of neuropsychological and motor tests. The arachnoid cyst volume decreased postoperatively (p < 0.0001), but there was no relationship between volume reduction and clinical improvement.

CONCLUSIONS

The results of this study speak against objectively verifiable improvement following surgical treatment in adults with intracranial arachnoid cysts.

Prepontine arachnoid cyst presenting with headache and diplopia: A case report study

Background:

Arachnoid cysts are found everywhere in cerebrospinal axis, most often in the middle cranial fossa. They are very rare in prepontine location.

Case Description:

In this study, we report a 26-year-old female presenting with a 3-month history of headache and diplopia. On physical examination, she had clinical manifestations of sixth cranial nerve palsy. Magnetic resonance imaging revealed a prepontine arachnoid cyst with extension into interpeduncular and suprasellar cisterns. Computed tomography scan demonstrated no evidence of hydrocephalus. The patient was treated surgically by endoscopic fenestration of the cyst with endonasal transsphenoidal approach. The cyst was opened to prepontine, interpeduncular, and suprasellar cisterns.

Conclusion:

Endoscopic endonasal fenestration of the cyst to adjacent cistern may be safe in prepontine arachnoid cysts with sellar and suprasellar extension; it may be effective and less invasive compare to transcranial approach.

Cognitive disorders in a patient with an arachnoid cyst of the sylvian fissure and improvement after surgical treatment: Case description

Arachnoid cysts cause a wide spectrum of clinical symptoms. Often it is difficult to clearly establish the relation between the presence of an arachnoid cyst and problems reported by the patient, which may, although not necessarily, be due to chronically elevated intracranial pressure. In recent years, increasing attention is paid to cognitive disorders accompanying arachnoid cysts, such as memory disorders, attention disorders, or language function disorders. This article presents a case of an 11-year-old patient, treated at the University Children's Hospital in Cracow for an arachnoid cyst, located in the left middle cranial fossa. This analysis is focused on the description of cognitive and intellectual deficits of the child, as well as the discussion on their connection with the arachnoid cyst. Prior to the neurosurgical procedure, the boy presented significant deficits in cognitive functions, especially mnestic and attention functions and, also, a quite low level of intellectual functioning. Neuropsychological examination performed after the procedure indicated a significant improvement of cognitive functioning for all the functions, as well as a higher level of intellectual functioning. This analysis attempts to answer whether and to what extent the child still suffers from cognitive deficits from the organic lesions.

Ophthalmological symptoms in children with intracranial cysts

The purpose of this study was to perform an ophthalmological assessment in children with intracranial cysts and to assess the correlation between the occurrence of cysts and visual disorders. The documentation of 46 children with intracranial cysts, monitored by the Children’s Outpatient Ophthalmology Clinic, Poznan, Poland was analysed. The best corrected visual acuity (BCVA), the alignment of the eyes, visual evoked potentials (VEP), comprehensive eye examination were performed in all patients. Additional ophthalmological tests were conducted to eliminate other causes of decreased visual acuity.Included in the final analysis were 26 children (52 eyes). The average age at the last visit was 10.3 years. Sixteen children (61.5%) had arachnoid cysts located in the posterior cranial fossa, 3 children (11.5%) in the middle cranial fossa, while 7 children (27%) had a pineal cyst. Decreased BCVA was found in 13 children, abnormal VEP in 13, strabismus in 14 patients (53.9%), nystagmus in 5 patients (19.2%), and double vision in 2 patients (7.7%). Numerous visual disorders in children with intracranial cysts suggest the necessity to carry out enhanced ophthalmological diagnostics in these patients. In the examined patient group, visual disorders occurred mostly in the case of arachnoid cysts of the posterior fossa.

Prevalence of Abnormal Magnetic Resonance Imaging Findings in Children with Persistent Symptoms after Pediatric Sports-Related Concussion

A subset of patients experience persistent symptoms after pediatric concussion, and magnetic resonance imaging (MRI) is commonly used to evaluate for pathology. The utility of this practice is unclear. We conducted a retrospective cohort study to describe the MRI findings in children with concussion. A registry of all patients seen at our institution from January 2010 through March 2016 with pediatric sports-related concussion was cross-referenced with a database of radiographical studies. Radiology reports were reviewed for abnormal findings. Patients with abnormal computed tomographies or MRI scans ordered for reasons other than concussion were excluded. Among 3338 children identified with concussion, 427 underwent MRI. Only 2 (0.5%) had findings compatible with traumatic injury, consisting in both of microhemorrhage. Sixty-one patients (14.3%) had abnormal findings unrelated to trauma, including 24 nonspecific T₂ changes, 15 pineal cysts, eight Chiari I malformations, and five arachnoid cysts. One child underwent craniotomy for a cerebellar hemangioblastoma after presenting with ataxia; another had cortical dysplasia resected after seizure. The 2 patients with microhemorrhage each had three previous concussions, significantly more than patients whose scans were normal (median, 1) or abnormal without injury (median, 1.5; p = 0.048). MRI rarely revealed intracranial injuries in children post-concussion, and the clinical relevance of these uncommon findings remains unclear. Abnormalities unrelated to trauma are usually benign. However, MRI should be thoughtfully considered in children who present with concerning or atypical symptoms.

Long-term endocrine outcome of suprasellar arachnoid cysts

OBJECTIVE Due to their distinct location, suprasellar arachnoid cysts are known to cause a wide variety of problems, such as hydrocephalus, endocrine symptoms, and visual abnormalities. The long-term outcome of these cysts has not been elucidated. To find out the long-term outcome of suprasellar arachnoid cysts, a retrospective review of the patients was performed. The neurological and endocrine symptoms were thoroughly reviewed. METHODS Forty-five patients with suprasellar arachnoid cysts, with an average follow-up duration of 9.7 years, were enrolled in the study. A comprehensive review was performed of the results of follow-up regarding not only neurological symptoms but also endocrine status. The outcomes of 8 patients who did not undergo operations and were asymptomatic or had symptoms unrelated to the cyst were included in the series. RESULTS Surgery was most effective for the symptoms related to hydrocephalus (improvement in 32 of 32), but endocrine symptoms persisted after surgery (4 of 4) and required further medical management. More surprisingly, a fairly large number of patients (14 of 40; 1 was excluded because no pre- or postoperative endocrine evaluation was available) who had not shown endocrine symptoms at the time of the initial diagnosis and treatment later developed endocrine abnormalities such as precocious puberty and growth hormone deficiency. The patients with endocrine symptoms detected during the follow-up included those in both the operated (n = 12 of 32) and nonoperated (n = 2 of 8) groups who had been stable during follow-up since the initial diagnosis. CONCLUSIONS This study implies that patients with suprasellar arachnoid cysts can develop late endocrine problems during follow-up, even if other symptoms related to the cyst have been successfully treated. Hence, patients with these cysts need long-term follow-up for not only neurological symptoms but also endocrine abnormalities.

[Clinical magnetic resonance imaging : Frequent incidental cerebral findings]

The increasing use of magnetic resonance imaging (MRI) in clinical diagnostics means that patients and physicians are confronted more often with incidental findings. In the literature there are fluctuating data on the incidence of such findings and guidelines concerning the further procedure exist in only very few cases, such as incidental aneurysms and pituitary adenomas. The diagnostic and therapeutic implications which can be derived from incidental findings depend on multiple factors, such as anatomical location, patient age, comorbidity and patient wishes. For this reason it often makes sense to refer patients with incidental findings to an interdisciplinary neurological center at an early stage. In this review frequent incidental cerebral findings, epidemiological data, imaging criteria and, where possible, recommendations for the further procedure are shown.

Incidental findings on routine brain MRI scans in preterm infants

OBJECTIVE

Many neonatal intensive care units (NICUs) have adopted the practice of performing routine brain MRI in very low birth weight (VLBW) infants at term-equivalent age in order to better evaluate prematurity-related acquired lesions. A number of unexpected brain abnormalities of potential clinical significance can be visualised on routine scans as well. The aim of our study was to describe these incidental findings (IFs) in a VLBW population and to assess their clinical significance.

STUDY DESIGN

We retrospectively reviewed a series of brain MRI scans performed in VLBW infants consecutively admitted to our NICU between November 2011 and November 2014. IFs on brain MRI, which were not detected by cranial ultrasound nor suspected clinically, were registered. Clinical significance of IF was assessed in terms of need of further diagnostic or therapeutic interventions.

RESULTS

IFs were detected in 28 out of 276 VLBW infants (10.1%). In total, 21 cases (7.6%) required an intervention, which was only diagnostic in 16 cases, and both diagnostic and therapeutic in 5 cases. In the remaining seven cases (2.5%), no further action was considered necessary.

CONCLUSIONS

This study suggests that IFs on brain MRI of VLBW infants are not rare. In our population, most of them required a diagnostic or therapeutic intervention. The need and appropriateness of routine MRI scanning in VLBW at term-equivalent age are still subject of debate, and we believe our data can contribute meaningfully to this discussion.

Sellar and Parasellar Imaging

The skull base is a complex anatomical region that harbors many important neurovascular structures in a relatively confined space. The pathology that can develop at this site is varied, and many disease processes may present with similar clinical and neuroimaging findings. While computed tomography maintains a role in the evaluation of many entities and can, for instance, delineate osseous erosion with great detail and characterize calcified tumor matrices, magnetic resonance imaging (MRI) is the mainstay in the neuroimaging assessment of most pathology occurring at the skull base. Various MRI sequences have proven to be robust tools for tissue characterization and can provide information on the presence of lipids, paramagnetic and diamagnetic elements, and tumor cellularity, among others. In addition, currently available MRI techniques are able to generate high spatial resolution images that allow visualization of cranial nerves and their involvement by adjacent pathology. The information obtained from such examinations may aid in the distinction of these disease processes and in the accurate delineation of their extent prior to biopsy or treatment planning.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Surgery for intracranial arachnoid cysts in children-a prospective long-term study

PURPOSE

Intracranial arachnoid cysts are cystic malformations found in both adults and children. While many are asymptomatic, some cause symptoms and warrant surgical treatment. In this prospective population-based study, we aimed to study the short- and long-term outcome after surgical intervention in children with arachnoid cysts referred to our centre.

METHODS

Twenty-seven pediatric patients (13 f. 14 m, mean age 9.4 years) with de novo cysts were consecutively included during a 5-year period. The presenting symptoms were headache (n = 12), balance disturbance and dizziness (n = 6), seizures (n = 6), hydrocephalus (n = 5), and macrocephaly (n = 1). Twenty-two patients underwent surgical treatment with either microsurgical (n = 17) or endoscopic fenestration (n = 5) of the cyst wall. Cyst volume was measured with OsiriX® software pre- and postoperatively. Short-term and long-term follow-up of all patients was conducted 3 months and 8.6 years (7-10.5 years) postoperatively.

RESULTS

Three months after surgery, 59 % of the patients were improved regarding at least one major complaint, and average cyst volume was reduced to 33.3 ml (0-145 ml). At the long-term follow-up of 8.6 years, 77 % of the patients were improved regarding at least one symptom but subjective symptoms remained in 59 %. There was no permanent postoperative morbidity. We found no association between radiological reduction of cyst volume and clinical improvement.

CONCLUSION

Our findings support a restrictive attitude to surgery for intracranial arachnoid cysts, in the absence of objectively verified symptoms and signs or obstruction of CSF pathways.

A refractory arachnoid cyst presenting with tremor, expressive dysphasia, and cognitive decline

Background:

Arachnoid cysts are common incidental findings on intracranial imaging, although they are rarely symptomatic.

Case Description:

We present a case of a 49 year-old woman with a recurrent left supraorbital arachnoid cyst who developed staring spells, expressive dysphasia, and tremor after cyst fenestration and cystoperitoneal shunting. Her symptoms resolved after removing the shunt valve and creating a valveless system. The case is discussed and the literature reviewed.

Conclusion:

We present a case of a recurrent arachnoid cyst that developed worsening and new symptoms after cysto-peritoneal shunting with a programmable valve, which reducing the pressure in the cyst resulted in remarkable resolution of her symptoms.

Rapid Visual Deterioration Caused by Posterior Fossa Arachnoid Cyst

Posterior fossa is a site next to the middle fossa where arachnoid cyst frequently occurs. Generally, most arachnoid cysts are asymptomatic and are found incidentally in most cases. Although arachnoid cysts are benign and asymptomatic lesions, patients with posterior fossa arachnoid cysts often complain of headaches, gait disturbance, and ataxia due to the local mass effects on the cerebellum. We observed a patient with a posterior fossa arachnoid cyst who had visual symptoms and a headache, but did not have gait disturbance and ataxia. We recommended an emergency operation for decompression, but the patient refused for personal reasons. After 7 days, the patient revisited our hospital in a state of near-blindness. We suspected that the arachnoid cyst induced the hydrocephalus and thereby the enlarged third ventricle directly compressed optic nerves. Compressed optic nerves were rapidly aggravated during the critical seven days; consequently, the patient's vision was damaged despite the operation. Considering the results of our case, it is important to keep in mind that the aggravation of symptoms cannot be predicted; therefore, symptomatic arachnoid cysts should be treated without undue delay.

Retirement-from-sport considerations following pediatric sports-related concussion: case illustrations and institutional approach

The decision to advise an athlete to retire from sports following sports-related concussion (SRC) remains a persistent challenge for physicians. In the absence of strong empirical evidence to support recommendations, clinical decision making must be individualized and should involve a multidisciplinary team of experts in concussion and traumatic brain injury. Although previous authors have advocated for a more conservative approach to these issues in child and adolescent athletes, there are few reports outlining considerations for this process among this unique population. Here, the authors use multiple case illustrations to discuss 3 subgroups of clinical considerations for sports retirement among pediatric SRC patients including the following: those with structural brain abnormalities identified on neuroimaging, those presenting with focal neurological deficits and abnormalities on physical examination, and those in whom the cumulative or prolonged effects of concussion are suspected or demonstrated. The authors' evolving multidisciplinary institutional approach to return-to-play and retirement decision making in pediatric SRC is also presented.

Sports participation with arachnoid cysts

OBJECT There is currently no consensus on the safety of sports participation for patients with an intracranial arachnoid cyst (AC). The authors' goal was to define the risk of sports participation for children with this imaging finding. METHODS A survey was prospectively administered to 185 patients with ACs during a 46-month period at a single institution. Cyst size and location, treatment, sports participation, and any injuries were recorded. Eighty patients completed at least 1 subsequent survey following their initial entry into the registry, and these patients were included in a prospective registry with a mean prospective follow-up interval of 15.9 ± 8.8 months. RESULTS A total 112 patients with ACs participated in 261 sports for a cumulative duration of 4410 months or 1470 seasons. Of these, 94 patients participated in 190 contact sports for a cumulative duration of 2818 months or 939 seasons. There were no serious or catastrophic neurological injuries. Two patients presented with symptomatic subdural hygromas following minor sports injuries. In the prospective cohort, there were no neurological injuries CONCLUSIONS Permanent or catastrophic neurological injuries are very unusual in AC patients who participate in athletic activities. In most cases, sports participation by these patients is safe.

Children With Arachnoid Cysts Who Sustain Blunt Head Trauma: Injury Mechanisms and Outcomes

OBJECTIVES

Arachnoid cysts are abnormal intracranial fluid collections, and there is concern that these cysts may bleed or rupture following blunt head trauma. Our objective was to determine the risk of cyst-related complications in a cohort of children with arachnoid cysts who were evaluated for head trauma.

METHODS

We analyzed the Pediatric Emergency Care Applied Research Network (PECARN) head trauma public use data set, which was the product of a study that enrolled children with blunt head trauma from June 2004 to September 2006. We identified children with arachnoid cysts on cranial computed tomography (CT) and described the patient demographics, mechanisms of injury, clinical presentations, CT evidence of traumatic brain injury (TBI), and clinical outcomes. Clinically important TBI was defined as TBI leading to: 1) death from TBI, 2) neurosurgical intervention, 3) intubation for > 24 hours for the TBI, or 4) hospitalization for 2 or more nights for the head injury in association with TBI on CT.

RESULTS

Data were available for 43,399 children who sustained blunt head trauma, of whom 15,899 had cranial CT scans obtained and 68 (0.4%) had arachnoid cysts. Falls were the most common mechanisms of injury (47%) and 87% of children had either moderate or severe injury mechanisms. Glasgow Coma Scale (GCS) scores ranged from 6 to 15, with 61 (90%) having GCS scores of 15. Two of the children with arachnoid cysts had TBIs on CT, one of which was clinically important. There were no identified cases of arachnoid cyst-related bleeding or complications.

CONCLUSIONS

In this cohort of 68 children with arachnoid cysts who sustained head trauma, none demonstrated cyst-related bleeding or complications. This suggests the risk of arachnoid cyst-related complications in children following blunt head trauma is low and evaluation should align with existing clinical decision rules.

Prevalence and symptoms of intracranial arachnoid cysts: a population-based study

To investigate the prevalence of intracranial arachnoid cysts in a large population-based sample. We also aimed to assess the association between arachnoid cysts and cognitive impairment, depression, epilepsy, headache, dizziness, previous head trauma, hip fractures, and mortality. A population-based cohort and nested case-control study. The sample comprised representative populations (n = 1235) aged ≥ 70 years. All participants underwent baseline neuropsychiatric examinations, including computed tomography (CT) of the brain, between 1986 and 2000. All CT scans were examined for arachnoid cysts. Headache, dizziness, history of head trauma, dementia, depression, epilepsy, and hip fracture were assessed using data from clinical examinations, interviews and the Swedish hospital discharge register. Cognition was assessed using the Mini-Mental Status Examination, and depressive symptoms using the Montgomery-Åsberg Depression Rating Scale. Date of death was obtained from the National Swedish Death Registry. The prevalence of arachnoid cysts was 2.3 % (n = 29), with no significant difference between men and women. Probands with and without cysts had the same frequency of headache, dizziness, previous head trauma, cognitive impairment, and depressive symptoms. Furthermore, there were no differences regarding the prevalence of dementia, depression, epilepsy, or previous hip fracture. Arachnoid cysts were not associated with increased mortality. Arachnoid cysts are common incidental finding, with the same rate in men and women, and are probably asymptomatic. The lack of relation with symptoms like headache, dizziness and cognitive impairment suggest caution in ascribing symptoms to incidentally discovered arachnoid cysts and a restrictive attitude to treatment.

A Novel Bilateral Approach for Suprasellar Arachnoid Cysts: A Case Report

The endoscopic method is used to treat suprasellar arachnoid cysts (SACs) but it is sometimes difficult to make sufficiently sized fenestrations. Creating a larger fenestration on the cyst wall is preferable to prevent closure of the stoma. In this paper, we report a novel endoscopic approach for SAC treatment in which we use bilateral burr holes to achieve a more extensive cyst fenestration. A 7-year-old girl was referred to our hospital because of incidentally detected hydrocephalus by computed tomography scans. Physical examination did not show any signs of intracranial hypertension, but a digital impression of her skull on X-ray implied chronic intracranial hypertension. Magnetic resonance imaging (MRI) revealed enlargement of both lateral ventricles and a cystic mass occupying the third ventricle. We performed cyst wall fenestration using a bilateral approach in which we created two burr holes to introduce a flexible endoscope and a rigid endoscope. The cyst wall was held by forceps with the flexible endoscope, and resection of the cyst wall was achieved by using a pair of scissors with the rigid endoscope. There were no postoperative complications, and MRI performed 1 year after treatment showed disappearance of the superior part of the cyst wall.

Tectal Lesions in Children: A Long-Term Follow-Up Volumetric Tumor Growth Analysis in Surgical and Nonsurgical Cases

BACKGROUND/AIMS

Different tectal masses have been described; most are low-grade gliomas. Only 20-30% of all lesions grow, as shown on follow-up MRIs, requiring surgical resection at some point. The aim of this study is to describe the experience of a single institution managing pediatric patients with tectal lesions.

METHODS

We retrospectively studied and analyzed 40 children with tectal lesions managed from 1990 to 2006; the mean age at diagnosis was 9.4 years. A volumetric classification was used to analyze tumor growth trends. More than 1 year of imaging follow-up was available for 23 patients.

RESULTS AND CONCLUSION

Medium- and large-volume-size lesions were associated with the need for surgery. About half of the nonsurgical lesions grew at least 50% over a period of 4.5 years and did not require surgical resection.

Analysis of supratentorial cystic abnormalities using in utero MR imaging

OBJECTIVE

Our anecdotal experience from foetal neuroimaging studies suggests that there are often significant disagreements between the findings of ultrasonography (USS) and in utero MR (iuMR) imaging in cases of antenatally detected supratentorial extra-axial cysts. Although this is a relatively rare clinical situation, it warrants further investigation because of the high risk of other intracranial abnormalities that are likely to cause long-term neurodevelopmental problems.

METHODS

We reviewed 957 consecutive referrals for iuMR of the foetal brain over a 3.5-year period and studied all cases where the referral from USS described supratentorial extra-axial cysts in the foetus. The iuMR imaging was reviewed, and a comparison between the results of the two examinations was made.

RESULTS

Supratentorial extra-axial cysts were an unusual referral for iuMR occurring in only 13/957 (1.4%) of cases. The findings on USS and iuMR imaging were conflicting in all 13 cases with intracranial pathology being excluded on iuMR imaging in 4 cases and more significant pathology being shown in 9 cases. Abnormalities of the corpus callosum were recognized in association with a cyst in eight cases, and this was recognized in only two cases on USS. Six of those cases also had abnormalities of cortical formation.

CONCLUSION

iuMR imaging should be used in the assessment of pregnancies in which a supratentorial extra-axial cyst has been detected on USS. This is based on the improved primary diagnosis and a high rate of associated brain abnormalities not detected on USS.

ADVANCES IN KNOWLEDGE

Our retrospective observational study examines a range of foetal intracranial abnormalities which are better defined using iuMRI. This is a previously described spectrum of neurodevelopmental anomalies which we suggest would benefit from MRI.

Shunt placement after cyst fenestration for middle cranial fossa arachnoid cysts in children

OBJECT Some pediatric patients with middle cranial fossa arachnoid cysts present with symptoms of increased intracranial pressure (ICP) and require shunt placement after a cyst fenestration. However, factors concerning increased ICP after fenestration followed by shunt placement have not been elucidated. This study evaluated factors that are associated with shunt placement following cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. METHODS Twenty-six pediatric patients with middle cranial fossa arachnoid cysts who were surgically treated at a single institution between 2004 and 2013 were retrospectively identified. The surgical indications for middle cranial fossa arachnoid cysts were as follows: 1) arachnoid cysts associated with symptoms such as headache and abnormally enlarging head circumference; 2) progressively expanding arachnoid cysts; and 3) large arachnoid cysts such as Galassi Type III. A cyst fenestration was performed as a first-line treatment, and shunt placement was required if symptoms associated with increased ICP were found following fenestration. The risk factors evaluated included age, sex, presenting symptoms, the presence of head enlargement, progressive cyst expansion, and subdural hematoma/hygroma. RESULTS Four patients (15.4%) required shunt placement after cyst fenestration. Younger age, abnormal head enlargement, and progressive cyst expansion before fenestration were significantly associated with the need for shunt placement following fenestration. Arachnoid cysts decreased in size in 22 patients (84.6%) after fenestration and/or shunt placement. The presence of symptoms was not associated with postoperative cyst size in this study. CONCLUSIONS In this study, younger age, abnormal head enlargement, and progressive cyst expansion were risk factors for shunt placement after cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. It is important to consider that cyst fenestration may not be effective because of a latent derangement of CSF circulation in patients with these risk factors.

Multivariate analyses applied to fetal, neonatal and pediatric MRI of neurodevelopmental disorders

Multivariate analysis (MVA) is a class of statistical and pattern recognition methods that involve the processing of data that contains multiple measurements per sample. MVA can be used to address a wide variety of medical neuroimaging-related challenges including identifying variables associated with a measure of clinical importance (i.e. patient outcome), creating diagnostic tests, assisting in characterizing developmental disorders, understanding disease etiology, development and progression, assisting in treatment monitoring and much more. Compared to adults, imaging of developing immature brains has attracted less attention from MVA researchers. However, remarkable MVA research growth has occurred in recent years. This paper presents the results of a systematic review of the literature focusing on MVA technologies applied to neurodevelopmental disorders in fetal, neonatal and pediatric magnetic resonance imaging (MRI) of the brain. The goal of this manuscript is to provide a concise review of the state of the scientific literature on studies employing brain MRI and MVA in a pre-adult population. Neurological developmental disorders addressed in the MVA research contained in this review include autism spectrum disorder, attention deficit hyperactivity disorder, epilepsy, schizophrenia and more. While the results of this review demonstrate considerable interest from the scientific community in applications of MVA technologies in pediatric/neonatal/fetal brain MRI, the field is still young and considerable research growth remains ahead of us.

Exploring predictors of surgery and comparing operative treatment approaches for pediatric intracranial arachnoid cysts: a case series of 83 patients

OBJECT

Although intracranial arachnoid cysts are a common incidental finding on pediatric brain imaging, only a subset of patients require surgery for them. For the minority who undergo surgery, the comparative effectiveness of various surgical approaches is debated. The authors explored predictors of surgery and compared operative techniques for pediatric patients with an intracranial arachnoid cyst seen at a tertiary care center.

METHODS

The authors reviewed records of pediatric patients with an intracranial arachnoid cyst. For each patient, data on baseline characteristics, the method of intervention, and surgical outcomes for the initial surgery were extracted, and cyst size at diagnosis was calculated (anteroposterior × craniocaudal × mediolateral). Baseline variables were analyzed as predictors of surgery by using logistic regression modeling, excluding patients whose surgery was not related to cyst size (i.e., those with obstructive hydrocephalus secondary to the cyst compressing a narrow CSF flow pathway or cyst rupture/hemorrhage). Data collected regarding surgical outcomes were analyzed descriptively.

RESULTS

Among 83 pediatric patients with an intracranial arachnoid cyst seen over a 25-year period (1989-2013), 27 (33%) underwent surgery; all had at least 1 cyst-attributed symptom/finding. In the multivariate model, age at presentation and cyst size at diagnosis were independent predictors of surgery. Cyst size had greater predictive value; specifically, the area under the curve for the receiver-operating-characteristic curve was 0.89 (95% CI 0.82-0.97), with an ideal cutoff point of ≥ 68 cm(3). This cutoff point had 100% sensitivity (95% CI 79%-100%), 75% specificity (95% CI 61%-85%), a 53% positive predictive value (95% CI 36%-70%), and a 100% negative predictive value (95% CI 91%-100%); the positive likelihood ratio was 4.0 (95% CI 2.5-6.3), and the negative likelihood ratio was 0 (95% CI 0-0.3). Although the multivariate model excluded 7 patients who underwent surgery (based on prespecified criteria), excluding these 7 cases did not change the overall findings, as shown in a sensitivity analysis that included all the cases. Descriptive results regarding surgical outcomes did not indicate any salient differences among the surgical techniques (endoscopic fenestration, cystoperitoneal shunting, or craniotomy-based procedures) in terms of symptom resolution within 6 months, need for reoperation to date, cyst-size change from before the operation, morbidity, or mortality.

CONCLUSIONS

The results of these exploratory analyses suggest that pediatric patients with an intracranial arachnoid cyst are more likely to undergo surgery if the cyst is large, compresses a narrow CSF flow pathway to cause hydrocephalus, or has ruptured/hemorrhaged. There were no salient differences among the 3 surgical techniques for several clinically important outcomes. A prospective multicenter study is required to enable more robust analyses, which could ultimately provide a decision-making framework for surgical indications and clarify any differences in the comparative effectiveness of surgical approaches to treating pediatric intracranial arachnoid cysts.

Neuroimaging findings in pediatric sports-related concussion

OBJECT

The goal in this review was to summarize the results of clinical neuroimaging studies performed in patients with sports-related concussion (SRC) who were referred to a multidisciplinar ypediatric concussion program.

METHODS

The authors conducted a retrospective review of medical records and neuroimaging findings for all patients referred to a multidisciplinary pediatric concussion program between September 2013 and July 2014. Inclusion criteria were as follows: 1) age ≤ 19 years; and 2) physician-diagnosed SRC. All patients underwent evaluation and follow-up by the same neurosurgeon. The 2 outcomes examined in this review were the frequency of neuroimaging studies performed in this population (including CT and MRI) and the findings of those studies. Clinical indications for neuroimaging and the impact of neuroimaging findings on clinical decision making were summarized where available. This investigation was approved by the local institutional ethics review board.

RESULTS

A total of 151 patients (mean age 14 years, 59% female) were included this study. Overall, 36 patients (24%) underwent neuroimaging studies, the results of which were normal in 78% of cases. Sixteen percent of patients underwent CT imaging; results were normal in 79% of cases. Abnormal CT findings included the following: arachnoid cyst (1 patient), skull fracture (2 patients), suspected intracranial hemorrhage (1 patient), and suspected hemorrhage into an arachnoid cyst (1 patient). Eleven percent of patients underwent MRI; results were normal in 75% of cases. Abnormal MRI findings included the following: intraparenchymal hemorrhage and sylvian fissure arachnoid cyst (1 patient); nonhemorrhagic contusion (1 patient); demyelinating disease (1 patient); and posterior fossa arachnoid cyst, cerebellar volume loss, and nonspecific white matter changes (1 patient).

CONCLUSIONS

Results of clinical neuroimaging studies are normal in the majority of pediatric patients with SRC. However, in selected cases neuroimaging can provide information that impacts decision making about return to play and retirement from the sport.

Dual-trajectory Approach for Simultaneous Cyst Fenestration and Endoscopic Third Ventriculostomy for Treatment of a Complex Third Ventricular Arachnoid Cyst

Objectives: We present a case of a multiloculated third ventricular arachnoid cyst to describe a novel technique for definitive management of these lesions via direct endoscopic fenestration and CSF diversion utilizing separate trajectories that offers superior visualization and avoids forniceal injury.

Methods and Results: We present a case of a 33-year-old woman with progressive headache and worsened vision, a known history of a multiloculated third-ventricular arachnoid cyst, and imaging findings consistent with cyst expansion and worsened obstructive hydrocephalus. We then describe the dual-trajectory approach for simultaneous cyst fenestration and endoscopic third ventriculostomy that ultimately resulted in successful treatment of her cyst and hydrocephalus.

Conclusions: Dual-trajectory endoscopic approach utilizing double burr holes should be considered when addressing lesions of the third ventricle causing obstructive hydrocephalus.

Image diagnosis: arachnoid cyst

A 14-year-old boy presented with 3 months of generalized headache that had increased in intensity and frequency with associated light-headedness. Primary arachnoid cysts result from developmental abnormalities; more rare secondary cysts develop as a result of head injury, meningitis, tumors, or as a complication of brain surgery.

[Epidemiology and classification of arachnoid cysts in children]

The prevalence of arachnoid cysts in children is 1-3%. They are more frequent in boys. They can be located intracranially or in the spine. Intracranial cysts are classified as supratentorial, infratentorial, and supra-infratentorial (tentorial notch). Supratentorial are divided into middle cranial fossa, convexity, inter-hemisferic, sellar region, and intraventricular. Infratentorial are classified into supracerebellar, infracerebellar, hemispheric, clivus, and cerebellopontine angle. Finally spinal arachnoid cysts are classified taking into account whether they are extra- or intradural, and nerve root involvement.