Neurocognitive and psychological profiles in pediatric arachnoid cyst

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.

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

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

Temporosylvian arachnoid cysts in children. Part 2: Postoperative neuropsychological and clinical improvement

OBJECTIVE

The authors' objective was to study clinical, imaging, and neuropsychological changes in children who underwent surgery for a temporal arachnoid cyst (TAC).

METHODS

Thirty-four children were prospectively assessed similarly at diagnosis and postoperatively (mean 14 months) with clinic visits, images, cognitive tests, and parental questionnaires on mood/behavior and executive functions. The scores were compared pre- and postoperatively for the entire cohort and individually. The scores of 25 children were also compared with a control group of 23 healthy age-matched children. Parents were administered an outcome questionnaire on average 4 years postoperatively.

RESULTS

The 34 children selected for surgery had signs of raised intracranial pressure (74%) and/or selective neuropsychological disorders presumably linked to cyst location (learning difficulties in 65%, cognitive difficulties in 56%, and mood/behavior difficulties in 47%). The majority of patients had a convex cyst (85%) and underwent microsurgical fenestration (85%). The TAC volume decreased ≥ 50% for 59% of children. On the Wechsler Intelligence Scale, the entire cohort significantly improved on Full Scale IQ and verbal and perceptual nonverbal indexes. Individually, nearly half of the children (47%) highly increased their scores (≥ 15 points) on at least one IQ index and 26% on at least two indexes. Language, working memory, episodic memory, and executive functions were also significantly improved. Improvements were more pronounced in patients with a preoperative heterogeneous profile with isolated lower scores and a left-sided cyst. Parental questionnaires showed reduction in anxiety, aggressiveness, social problems, and daily life executive disorders. Preschool-aged children improved significantly in language and verbal IQ, as did middle/high school-aged children in many domains. Individual analyses revealed improvement in 76% of cases. Cognitive scores were lower for patients preoperatively than for controls and were no longer significantly different postoperatively in verbal fluency, visual memory, and working memory. Four years later, 97% of parents described an improvement in their child, correlated with cognitive improvements.

CONCLUSIONS

Among children with a TAC, some have no clinical signs or neuropsychological difficulties, and others may show signs of raised intracranial pressure and/or specific neuropsychological disorders that impact daily life and require significant and long-lasting rehabilitation. In these cases, consideration may be given to surgical decompression. It is interesting to note that 76% of this surgically treated cohort improved regardless of the child's age, particularly in patients with selective disorders and an impact on daily life. However, a larger number of children will need to be investigated before the true benefit of such treatment can be known.

Temporosylvian arachnoid cysts in children. Part 1: Cognitive profile of children with a temporal cyst and impact of the cyst in daily life. A prospective study in 100 consecutive children

OBJECTIVE

The aim of this study was to determine the cognitive profile of children with a temporal arachnoid cyst (TAC) and its impact on daily life.

METHODS

The authors prospectively analyzed the cognitive and psychological profiles of 100 consecutive children relative to age and cyst characteristics (side, cyst size, and cyst shape: convex or nonconvex) and their outcome 4 years later.

RESULTS

Mean IQs were normal but with high heterogeneity on Full Scale IQ (FSIQ; range 59-150); 29% of children had at least one Wechsler index below the norm, in particular, Processing Speed and Working Memory Indexes. Impairments were observed in language for 31% of children, as well as in verbal memory (28%), visual memory (23%), executive function (21%), and visual attention (24%). Half of the children (50%) needed rehabilitation for learning difficulties, and 26% had academic difficulties. The parental questionnaire BRIEF (Behavior Rating Inventory of Executive Function) revealed significant executive dysfunctions in daily life for 22% of the children. One-third of the patients (34%) required psychotherapy for anxiety or social disorders, with higher rates in patients with a right-sided cyst and older children. Cyst size had very little neuropsychological impact. Convex cysts were significantly associated with worse performance than nonconvex cysts on all Wechsler indexes and FSIQ, and in language, verbal memory, attention, and visuospatial skills. Children with a convex cyst had significantly more executive and behavior difficulties in daily life and more psychotherapy than other children. The effect of cyst shape was independent of Galassi type and cyst side. Children with a ruptured cyst or an incidentally discovered cyst usually had a good cognitive level. Four years later, children without initial disorders remained stable, whereas those with difficulties who did not undergo surgery needed more rehabilitation and school adaptations.

CONCLUSIONS

This large cohort study revealed a varied profile of children with a TAC: at initial assessment, 50% had neuropsychological difficulties and needed rehabilitation and/or psychotherapy for learning or behavior difficulties, and 50% had no difficulties, which may explain the debate about this pathology. Patients with neuropsychological difficulties had a heterogeneous profile with normal intelligence but selective cognitive and/or behavior disorders that may have a long-term impact on their quality of life, particularly those with a right-sided cyst. A neuropsychological evaluation is not always necessary for a cyst discovered incidentally, but early evaluation is essential in patients with academic, learning, or psychological disorders. When assessment shows selective disorders presumably linked to cyst location, surgery may be considered, particularly for convex cysts, as this study revealed more effects in association with cyst shape than with cyst size and significantly poorer performance with a convex cyst.

Cut it out or wait it out? Case series of middle fossa arachnoid cysts presenting with psychiatric symptoms and a discussion of the ethics of neurosurgical management

Arachnoid cysts have been linked to neuropsychiatric morbidity. We describe two patients presenting with dissociative and manic symptoms believed to be associated with middle fossa arachnoid cysts. They were managed medically and remitted eventually, but symptoms were resistant. We briefly review the literature to discuss mechanisms by which cysts could cause symptoms and consider whether neurosurgical management would be appropriate. Although neurosurgery can be considered, its role is currently limited by practical and ethical considerations.

Surgical management of intracranial arachnoid cysts in pediatric patients: radiological and clinical outcome

OBJECTIVE

Congenital intracranial cysts account for a significant portion of intracranial lesions in the pediatric population. The efficiency of surgical treatment in a pediatric cohort with intracranial arachnoid cysts (ACs) at different locations regarding clinical symptoms and mass effect was evaluated.

METHODS

A retrospective study of all children who underwent surgical treatment of an intracranial AC during an 11-year period (2007-2018) was performed. Demographics, clinical symptoms, and radiological cyst size pre- and postoperatively, as well as the reoperation rate and possible treatment complications, were analyzed.

RESULTS

A total of 116 intracranial cysts at 8 different anatomical locations were surgically treated in 113 children (median age 5 years and 10 months) predominantly by endoscopic technique (84%). The complication rate was 3%, and the reoperation rate was 16%. Preoperative cyst enlargement was significantly more common in infants (p < 0.0001), as was the need for reoperation (p = 0.023). After a median radiological follow-up of 26 months, > 50% reduction of cyst volume was seen in 53 cysts (46%), and 47 cysts (40%) showed a 10%-50% reduction. Acute clinical symptoms improved: nausea and vomiting, accelerated head growth, and headaches improved at 100%, 92% and 89%, respectively. However, chronic symptoms responded less favorably after a median clinical follow-up of 26 months.

CONCLUSIONS

The strategy of predominantly endoscopic treatment with navigation planning is efficient to alleviate clinical symptoms and to significantly reduce the mass effect of pediatric intracranial cysts at different anatomical locations. The subgroup of infants requires close pre- and postoperative monitoring.

Cognition in Children with Arachnoid Cysts

Background: This study aims to evaluate if children with temporal arachnoid cysts (AC) have cognitive symptoms and if neurosurgery improves these. Methods: A prospective case series study including consecutive pediatric patients with temporal AC. The children underwent neuroradiology, neuroopthalmologic evaluation, and a standard electroencephalography (EEG). Additionally, a neuropsychologist performed a standardized set of evaluations, with a one-year follow-up consisting of Weschler Intelligence Scale for Children version IV (WISC-IV), FAS (for verbal fluency), Boston Naming Test (BNT, for visual naming ability) and NEPSY-II (Developmental NEuroPSYchological Assessment) for verbal memory. Results: Fifteen children, 9 boys and 6 girls, were evaluated and 11 underwent surgery. The Full Scale IQ subscore (FSIQ) improved from M = 84.8 to M = 93.0 (p = 0.005). The preoperative Verbal Comprehension Index (VCI) was in the low average range (M = 86.7), improving to a level within the average range (M = 94.7, p = 0.001). Preoperative Perceptual Speed Index (PSI) was in the below average range (M = 81.5), improving to a level within the average range (M = 92.5, p = 0.004). Conclusion: ACs are a common finding in a pediatric neurosurgical setting. Our data suggest that some temporal AC have a negative effect on general cognitive ability and that this impairment can be improved by surgery. We suggest a standardized evaluation, including comprehensive and validated neuropsychological assessment tools, to thoroughly assess symptoms as well as the postoperative outcome.

Anxiety and Depression in Patients with Intracranial Arachnoid Cysts-A Prospective Study

BACKGROUND

Arachnoid cysts yield cognitive deficits that are normalized after surgical cyst decompression.

OBJECTIVE

The present study aimed to investigate whether arachnoid cysts also affect symptoms of anxiety and depression, and if surgical cyst decompression leads to reduction of these symptoms.

METHODS

Twenty-two adult patients (13 men and 9 women) with symptomatic temporal or frontal cysts were included in this questionnaire (Hospital Anxiety and Depression Scale [HADS])-based prospective study. The mean time between answering the preoperative questionnaire and surgery was 37 days. The patients answered the same HADS questionnaire 3-6 months postoperatively.

RESULTS

Preoperatively, both patients with frontal (N = 4) and patients with temporal (N = 18) cyst had higher mean HADS anxiety scores than those found in the general population. For patients with temporal cyst, there was a significant or near-significant difference in anxiety and depression scores and the combined scores between those with right-sided cysts and those with left-sided cysts. Postoperatively, the HADS scores normalized and were no longer different from those of the general population. The difference in scores between patients with right and left temporal cyst also disappeared.

CONCLUSIONS

Patients with arachnoid cyst have higher levels of anxiety and depression than do the general population and these scores were normalized after decompressive cyst surgery. We further found a hemispheric asymmetry: patients with a right temporal cyst showed higher anxiety, depression, and combined scores than did patients with a left temporal cyst. Also, this disparity normalized after cyst decompression. Thus, arachnoid cysts seem to affect not only cognition but also the level of affective symptoms.

Microsurgical, endoscopic, and shunt management of pediatric temporosylvian arachnoid cysts: a comparative study

OBJECTIVE

Arachnoid cysts (ACs) are most frequently located in the middle cranial fossa. Some patients are asymptomatic whereas others exhibit signs of increased intracranial pressure, seizures, or cognitive and behavioral symptoms. When ACs do require treatment, the optimal surgical technique remains controversial. This study was conducted to assess the most effective surgical treatment for these cysts.

METHODS

The authors retrospectively reviewed 240 temporal intracranial ACs managed over a 25-year period in their pediatric neurosurgical unit. Pre- and posttreatment results were clinically and radiologically assessed.

RESULTS

A majority of male patients (74.6%) with an overall median age of 6.9 years were included. The mean cyst size was 107 cm3; the Galassi classification showed 99 (41.3%) type I, 77 (32.1%) type II, and 64 (26.7%) type III cysts. Forty-four ACs (18.3%) were diagnosed after rupture. Surgical management was performed by microsurgery (28.3%), endoscopic cyst fenestration (14.6%), cystoperitoneal shunting (CPS; 16.2%), or subdural shunting (10%). Furthermore, 74 children (30.8%) did not undergo operations. After a mean follow-up of 4.1 years, the mean percentage decrease in cyst volume and the overall rate of clinical improvement did not significantly differ. The endoscopy group had earlier complications and a shorter event-free survival (EFS) time (EFS at 3 years = 67.7%, vs 71.5% and 90.5% for CPS and microsurgery, respectively; p < 0.007) and presented with more subdural hematomas compared to the microsurgery group (p < 0.005). The microsurgery group also showed a tendency for longer cystocisternostomy permeability than the endoscopy group.

CONCLUSIONS

Concerning the management of unruptured symptomatic temporal ACs, microsurgery appears to be the most effective treatment, with longer EFS and fewer complications compared to shunting or endoscopy.

Psychopathological Influence of Middle Fossa Arachnoid Cysts in Young Men: Analysis of Korean Conscription Data

BACKGROUND

A few reported studies have documented psychotic syndromes secondary to a middle fossa arachnoid cyst (AC). However, the association between middle fossa ACs and psychopathological symptoms remains to be determined. The present study investigated the psychopathological effects of middle fossa ACs in young men.

METHODS

We reviewed military personal inventory test profiles and baseline demographic data of 19-year-old conscription examinees from February 2013 to December 2016. In total, 132 examinees with middle fossa ACs and 350 examinees with normal findings were enrolled in the present study. Two separate comparisons were performed. First, we compared the middle fossa AC group with the control group. Second, the middle fossa AC group was divided into 2 groups according to cyst size and compared with the control group.

RESULTS

Faking bad response behavior, infrequency, inconsistency, depression, schizophrenia, paranoia, and personality disorder cluster A scales were significantly associated with the presence of a middle fossa AC. Abnormal responses to the military personal inventory were significantly and positively correlated with cyst size. The prediction rate to show abnormal psychological results with the presence of an AC was estimated to be 60.7%-68.8%.

CONCLUSIONS

The presence of ACs and cyst size were associated with psychopathology in this select group of young men. The size-dependent psychopathological effects of ACs appear to result from a local mass effect on the brain.

Neurocognitive profile in children with arachnoid cysts before and after surgical intervention

OBJECTIVES

Treatment indications for arachnoid cysts are not clear. Some surgeons take improvement in neurocognitive function into account as a surgical indication for arachnoid cysts. However, only a few studies have evaluated the relationship between arachnoid cysts and neurocognitive function. Furthermore, studies that analyze neurocognitive function as an effect of arachnoid cyst surgery are even rarer. The purpose of this study was to analyze the neurocognitive function scores of children with arachnoid cysts before and after surgery and to examine whether surgical treatment led to improved neurocognitive function.

METHODS

From June 2009 to August 2012, data for 24 children diagnosed with arachnoid cysts who underwent surgery at Seoul National University Children's Hospital were analyzed. Pre-operative and post-operative cyst volume was assessed and neurocognitive function was tested using the Korean version of the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Bender-Gestalt Test (BGT). Comparison of pre- and post-operative profiles by laterality of the arachnoid cyst was performed.

RESULTS

Patients had age-appropriate full-scale intelligent quotients (FSIQ), verbal IQ (VIQ), and performance IQ (PIQ) pre-operatively, which were maintained after surgery. Of the subtests, Block Design showed significant improvement post-operatively (p = 0.021). This means that visuo-spatial integration and mental construction abilities were improved after surgery. Patients with left or right arachnoid cysts did not show statistically significant changes in FSIQ, VIQ, or PIQ after surgery (110.21 versus 113.95, p = 0.307; 108.92 versus 111.54, p = 0.368; 107.88 versus 111.04, p = 0.152, respectively). Subanalysis showed that the pre- and post-operation VIQ mean scores of the patients with right arachnoid cysts were significantly higher (p < 0.054) than those of the patients with left arachnoid cysts, and there was no significant change after the surgery.

INTERPRETATION

There was no significant association among cyst volume reduction, laterality, and clinical neurocognitive function improvement. The present findings indicate a limited role for surgical intervention in improving the intellectual abilities of children with arachnoid cysts.

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.

Neuropsychological improvement after posterior fossa arachnoid cyst drainage

PURPOSE

Posterior fossa arachnoid cysts (PFAC) are mostly considered as benign lesions of the cerebellum. Although many studies have shown the major role of the cerebellum in modulating movement, language, cognition, and social interaction, there are few studies on the cognitive impact and surgical decompression of PFAC.

METHODS

We present the cases of two brothers successively diagnosed with PFAC and neuropsychological delay. After multidisciplinary discussion with the boys' parents, it was decided to drain these lesions. Clinical signs, cerebral images, and neuropsychological status were assessed on admission and then 1 and 3 years after surgery.

RESULTS

At presentation, both children had mild cerebellar signs, associated with cognitive and visual-motor impairments and academic regression. CT scans revealed retrovermian cysts, which were shunted. Post-operatively, both brothers demonstrated improved visual-motor skills and behavior. At follow-up, we observed disappearance of dysarthria and academic delay and significant improvement in cognition especially at the intelligence scale and in language. Fine motor skills had improved but remained slower than the average and writing skills appeared limited.

CONCLUSION

Except for PFAC which impair cerebrospinal fluid circulation or which are responsible for a significant mass effect, most PFAC are usually considered as "asymptomatic" and do not require surgical treatment. The two cases reported herein suggest that these lesions might be responsible for some associated but potentially reversible neuropsychological impairment. In the future, clinical assessment should include neuropsychological evaluation to help inform decision for surgical decompression in these children with PFAC.

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.

The Influence of Frontal Lobe Tumors and Surgical Treatment on Advanced Cognitive Functions

Brain cognitive functions affect patient quality of life. The frontal lobe plays a crucial role in advanced cognitive functions, including executive function, meta-cognition, decision-making, memory, emotion, and language. Therefore, frontal tumors can lead to serious cognitive impairments. Currently, neurosurgical treatment is the primary method to treat brain tumors; however, the effects of the surgical treatments are difficult to predict or control. The treatment may both resolve the effects of the tumor to improve cognitive function or cause permanent disabilities resulting from damage to healthy functional brain tissue. Previous studies have focused on the influence of frontal lesions and surgical treatments on patient cognitive function. Here, we review cognitive impairment caused by frontal lobe brain tumors.

Arachnoid cysts with subdural hematoma or intracystic hemorrhage in children

Arachnoid cyst (AC) is a common congenital intracranial lesion in children. It may be complicated by subdural hematoma (SDH) and intracystic hemorrhage (ICH) to cause intracranial hypertension after minor head injury or spontaneously. However, because most bleeding after trauma is delayed, it is often overlooked. At the same time, it remains controversial for treatment of ACs complicated with SDH and ICH. So far, it lacks review, especially for pediatric patients who have ACs with SDH or ICH. Here, we report 3 pediatric cases in our department from 2010 to 2011. At the same time, we review 41 pediatric patients reported in the last 20 years. We conclude that a child with AC should be regularly followed up after minor head injury, and that therapy for children with complicated ACs should be more aggressive than for adults. The cyst wall should be resected, and communication between cyst and cerebral cistern should be established.

Benign extracerebral fluid collection in infancy as a risk factor for the development of de novo intracranial arachnoid cysts

OBJECT

Intracranial arachnoid cysts are a relatively common benign intracranial pathology, accounting for as many as 0.75%-1% of nontraumatic CNS lesions. Although it has already been demonstrated that rupture of arachnoid cysts may lead to subdural hematomas/hygromas, no study to date has investigated benign extracerebral collection in infancy as a possible predisposing factor for further development of arachnoid cysts.

METHODS

The authors performed a retrospective imaging and chart review of macrocephalic infants 12 months old or younger who were referred to neurosurgical care at OSF St. Francis Medical Center from 2003 to 2010, and who were diagnosed with benign extracerebral fluid collection in infancy on thin-slice (1-mm) head CT scans. Special attention was given to the investigation of risk factors for further development of de novo arachnoid cysts. Several epidemiological factors in the infants and mothers were analyzed, including gestational age at delivery, mode of delivery, mother's age at delivery, delivery complications, birth weight, age of macrocephaly development, degree of macrocephaly, family history of macrocephaly, prenatal and postnatal history of infection, fontanel status, presence of papilledema, previous history of head trauma, and smoking status. Imaging characteristics of the initial scans, such as location of subdural collection (frontal vs frontoparietal and frontotemporal) and presence of ventriculomegaly, were also evaluated. For those patients in whom arachnoid cysts were identified on subsequent CT scans, the size and location of the cysts were also analyzed.

RESULTS

The authors identified 44 children with benign extracerebral fluid collection in infancy. From this group, over a mean follow-up of 13 months (range 6-13 months), 18 children developed intracranial arachnoid cysts (a 40.9% incidence of de novo development of arachnoid cysts), with 27.8% presenting with bilateral cysts. In the multiple logistic regression analysis, infants who presented with an extracerebral collection restricted to the bilateral frontal region were more likely to develop intracranial arachnoid cysts (p = 0.035) than those with collections involving the frontotemporal and frontoparietal regions (odds ratio [OR] = 5.73). Additionally, children with benign extracerebral fluid collections and plagiocephaly were more likely to develop intracranial arachnoid cysts (p = 0.043) than those without plagiocephaly (OR = 4.96).

CONCLUSIONS

This is the first report in the neurosurgical literature demonstrating that benign extracerebral fluid collections in infancy may constitute a significant risk factor for development of de novo arachnoid cysts. These findings support a 2-hit hypothesis for the development of arachnoid cysts, in which the combination of an embryological defect in arachnoid development followed by a second event leading to impairment of CSF fluid absorption in early childhood could lead to abnormal CSF dynamics and the consequent expansion of fluid collections in the intraarachnoid spaces.