Intracranial arachnoid cysts – do they impair mental functions?

Co-morbid psychiatric disorders in children with arachnoid cyst

Arachnoid Cysts (AC) are benign lesions containing cerebrospinal fluid, and although most of them are asymptomatic, they can cause neurological symptoms like headaches, seizures, and neuropsychiatric problems. The aim of this study was to asses and document co-morbid psychiatric disorders in children with AC aged between 6 and 17. Wechsler Abbreviated Scale of Intelligence-Second Edition (WASI-II), a clinical measure used to assess the intelligence quotient (IQ) scores of the patients, Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version (K-SADS-PL; semi-structured interview) was used to assess psychiatric disorders among the patients. A total of 12 patients with AC was evaluated with an even distribution of males and females. Half of the patients had a normal IQ score with a mean IQ score of 104.5. Among patients with normal IQ scores, one patient had epilepsy and attention deficit hyperactivity disorder and two patients had epilepsy without any psychiatric disorder. The remaining six patients had moderate intellectual disability with a mean IQ of 48.2. Among them, three out of six had epilepsy and four had accompanying psychiatric disorders. It is therefore apparent that patients with AC have a high rate of co-morbid psychiatric disorders. Our study demonstrates that intellectual disability and psychiatric disorders should be evaluated in children with AC in the clinical settings.

Ruptured Sylvian arachnoid cysts: an update on a real problem

PURPOSE

Sylvian arachnoid cysts (SACs) are the most common type of arachnoid cysts and the most prone to undergo a rupture. This event is considered rare but potentially severe. No definite information is available on its occurrence or management. The goal of the present article is to provide an update on the epidemiological, etiological, and clinical aspects and the management of this peculiar clinical condition.

METHODS

A comprehensive review of the English literature of the last 40 years on this topic has been realized. Moreover, a personal series of children investigated and treated in the last 20 years is presented. These patients were managed as follows: (1) treatment of the subdural collection; (2) identification of candidates for surgical treatment of the residual cyst (brain MRI, perfusion brain MRI, prolonged invasive ICP monitoring (selected cases), EEG, neuropsychological tests); (3) surgical treatment of the cyst in the patients with pathological perfusion MRI and/or ICP measurement and/or clear neurophysiological and neuropsychological correlations.

RESULTS

A total of 446 patients (430 from the literature and 16 from the personal series), mainly children, adolescents, and young adults, have been analyzed leading to the following results: (1) SAC rupture is rare but not negligible (yearly risk of rupture: 0.04%; overall risk up to 10% in children affected by SCAs). Prophylactic surgery in asymptomatic cases is not advisable. (2) The mechanism of rupture is not known but an impact of SAC against the sphenoid wing and/or a direct injury on SAC through a thinned temporal bone, with possible laceration of the cyst wall vessels and/or tear of the bridging veins, can be hypothesized. A head injury is often not reported (may be misdiagnosed). (3) Subdural collection (hygroma > chronic hematoma) is the most common finding followed by intracystic bleeding, extradural hematoma, and other types of bleeding. Signs or symptoms of raised intracranial pressure are the most frequent ones. (4) The complication of the rupture is usually treated in emergency or in the acute period by burr hole or craniotomic evacuation of the subdural collection, although a conservative management is possible in some cases. Following the rupture, the majority of SACs are treated (70%), often at the same time of the complication, but no specific investigations are routinely performed to select candidates. According to our protocol, only 43.7% of SACs needed to be treated.

CONCLUSIONS

The "spontaneous" or posttraumatic rupture of SACs is a rare but potentially significant complication followed by a generally good outcome. The course of the cyst is independent from the outcome of the complication, consequently requiring specific investigations for individuating those lesions interfering with CSF dynamics and/or cerebral blood flow.

Psychotic Symptoms Associated With a Frontoparietal Arachnoid Cyst: The Role of Neuroimaging Studies in First-Episode Psychosis

Arachnoid cysts, although usually asymptomatic, can be associated with psychiatric symptoms, including delusions and hallucinations. The role of neuroimaging findings, particularly arachnoid cysts, and their influence on psychiatric symptoms is still controversial and debated. We present the case of a 56-year-old male who sought medical help for his psychotic symptoms, mainly paranoid delusions, and auditory and tactile hallucinations. Brain imaging studies at the time of admission revealed a large left frontoparietal arachnoid cyst. The patient was then started on psychiatric medication but did not show any sign of clinical improvement. After discussing the case with the patient´s neurosurgeon, it was decided to submit the patient to drainage of his arachnoid cyst. The patient was reevaluated two weeks after the procedure showing significant clinical improvement, particularly in his positive psychotic symptoms. The rapid improvement of the psychotic symptoms after removing the cyst suggests that, at least in part, the mass was contributing to the symptoms presented.

Seizures and Postictal Psychosis in a Patient With Retrocerebellar Arachnoid Cyst: A Case Report

Retrocerebellar arachnoid cysts are uncommon intracranial tumors, especially rare in adults. Although asymptomatic in the majority of cases, they may cause a variety of symptoms including convulsions. The causal involvement of these cysts in postictal psychosis, however, remains a topic that is not well-explained in the literature.

An 85-year-old Asian man presented with recurrent episodes of convulsions for the last seven months along with preceding headaches and postictal psychotic symptoms. MRI of the head revealed a retrocerebellar arachnoid cyst. He was commenced on symptomatic pharmacological therapy after he refused surgical intervention and remained symptom-free till his discharge from the hospital before being eventually lost to follow-up.

This case report focuses on the rare occurrence of a retrocerebellar arachnoid cyst with seizures and postictal psychosis and illustrates the necessity of further case studies and research to identify and explore the potential causal relationship between arachnoid cysts and psychosis.

Reversal of cognitive, behavioral, and language impairments after the left frontal arachnoid cyst fenestration in a pediatric patient

Background:

Arachnoid cysts (ACs) are cerebrospinal fluid-containing cysts located between the surface of the brain or spinal cord and arachnoid layer of the leptomeninges. ACs have been known to cause cognitive, language, and behavioral deficits and currently there is no standard treatment paradigm. Surgical indications include papilledema, increasing growth with mass effect causing neurological deficit, or rapid head growth, however, cognitive symptoms related to mass effect may not always be considered.

Case Description:

We present a 3-year-old male with an AC of the left anterior fossa causing frontal lobe compression with resultant behavioral, language, and cognitive deficits.

Conclusion:

Surgical intervention for AC decompression may be indicated when there are cognitive, behavioral, or language delays related to the mass effect and location of the AC. Neuropsychiatric testing or more advanced imaging studies may further support surgical treatment. After craniotomy for fenestration of the left frontal AC, there was drastic improvement in cognitive, language, and behavioral symptoms in our pediatric patient.

Are arachnoid cysts actually clinically mute in relation to neuropsychological symptoms? Cognitive functioning in children with AC of middle and cranial fossa

Aiming at being part of the discussion about the cognitive functioning of patients with arachnoid cysts (AC) and the value of neuropsychological testing in these patients, we present our study in which we investigated the cognitive functioning of 32 children with ACs of the middle cranial fossa. We compared the Stanford Binet 5 (SB 5) results obtained by the patients with the population mean values and analysed the relation between the patients' clinical details and the results of SB 5. The main conclusions of this research are: (1) In SB 5 tasks, the tested group performed worse than the population mean, which could be related to AC of the middle cranial fossa. Deficits concern especially visuospatial reasoning, quantitative reasoning, and knowledge. The obtained results indicate the coexistence of cognitive impairment and AC of the middle cranial fossa. (2) In patients with AC, neuroimaging information has only limited predictive ability regarding cognitive syndromes. (3) The complaints reported in the interview are not necessarily objectively reflected in the clinical assessment. Neuropsychological assessment should be part of the management of all patients with AC. (4) Cognitive deficits in patients with AC may become more pronounced with age. Accordingly, increasing school difficulties in these patients should be expected. In light of the above, there is a clear indication of the need for neuropsychological support and support in school functioning for patients with AC. (5) Neuropsychological control in patients with AC is crucial not only with regard to treatment decisions but primarily for monitoring school performance and providing these patients with adequate neuropsychological and psychological support.

COGNITIVE AND PSYCHOTIC SYMPTOMS IN A PATIENT WITH INFRATENTORIAL ARACHNOID CYST: CASE REPORT

We present a case of a patient with treatment resistant hallucinatory experiences with incidental finding of an arachnoid cyst localized in the posterior infratentorial cranial fossa dorsally to the cerebellum. Psychological testing revealed significant deficit of cognitive functions to the level of mild intellectual disability in a person that had previously finished high school with good grades. A combination of clozapine and lamotrigine led to significant improvement in mood and reduction of hallucinations, but without improvement in cognitive functions. We also performed a literature review of previously published case reports or case series of co-occurring posterior fossa arachnoid cyst and schizophrenia or psychosis or psychiatric symptoms using PubMed search and discuss some controversies considering their treatment outcome.

Epilepsy and cognitive deterioration as postoperative complications of the arachnoid cyst fenestration. Case report

OBJECTIVE

With the aim of contributing to the discussion on treatment of patients with arachnoid cysts (AC) and their neuropsychological functioning, we present the case of a patient who has undergone surgery of AC located in the left Sylvian fissure. Case description: The patient had no cognitive deficits and no seizures before the cyst's fenestration. After the procedure, however, occurrences of seizures have been observed. Along with the concomitant epileptic seizures, aphasia and serious memory problems also developed. The initial pharmacological treatment of the seizures brought about unsatisfactory results. The treatment was therefore modified a number of times and ultimately, seizures were brought under control to some extent. Despite the varied efforts at neuropsychological rehabilitation, cognitive impairment was still persistent up to a year after the surgery. Conclusions: 1) While referring patients with AC for surgery, one should always consider both the positive outcomes and the unintended and deleterious consequences. A cyst fenestration could in some cases lead to epilepsy and cause neuropsychological symptoms such as anomic aphasia and cognitive deterioration with memory function impairment. 2) Neurological patients, especially the ones qualified for surgery, should always undergo neuropsychological examination. The lack of data from presurgical neuropsychological examination may impact further treatment of neurosurgical patients.

Cognitive dysfunction and subjective symptoms in patients with arachnoid cyst before and after surgery

INTRODUCTION

Arachnoid cysts are congenital, benign lesions in the brain and are often incidental radiological findings. Frequently, the arachnoid cysts are left untreated; however, recent studies have shown that arachnoid cysts can cause cognitive dysfunction that affect quality of life. Moreover, the function can improve after surgical decompression. Hence, there is controversy regarding symptomatology and treatment effects of arachnoid cysts. The aim of the study was to analyse if arachnoid cysts can cause cognitive impairment and subjective symptoms and if these impairments are reversible after surgical treatment.

MATERIAL AND METHODS

Twenty-one consecutive patients with radiologically confirmed supratentorial arachnoid cysts were cognitively evaluated using a battery of seven neuropsychological tests. Twelve of these patients underwent surgery and were evaluated before and after surgery. The patients were also evaluated with neuropsychological testing after surgery. Further information was extracted from the medical records. The cognitive test results were compared to standard population values using z-test, and the test results from the surgically treated patients were compared before and after surgery using paired t-test.

RESULTS

The surgically treated patients had a statistically significant improvement of neurocognitive test results after surgery in six out of the seven tests (p < 0.05). The total patient group showed lower mean values in all tests when compared to standard population. Statistical significance was, however, only detected in two of the seven tests. All surgically treated patients reported diminished symptoms after surgery.

CONCLUSIONS

The patients with arachnoid cysts presented with cognitive dysfunction compared to the normal population which improved after surgical decompression. Arachnoid cysts should not be considered asymptomatic unless thoroughly evaluated with clinical and neuropsychological work-up.

Surgical decompression of arachnoid cysts leads to improved quality of life: a prospective study-long-term follow-up

BACKGROUND

In a previous study, we reported a short-term (6 months) postoperative improvement of health-related quality of life (Qol) in patients operated for an arachnoid cyst (AC). The aim was to investigate whether this initial improvement was permanent.

METHODS

A long-term (5 ± 2 years) prospective study comparing Qol and complaints before and 5 ± 2 years after surgical fenestration for AC in 76 adult patients, using the Short Form 36 (SF-36) scores, Glasgow Benefit Inventory (GBI) questionnaires, and Visual Analogue Scales (VAS) for headache and dizziness, similarly to what they did at short-term follow-up.

RESULTS

At short-term and long-term follow-ups, 73.4% and 82%, respectively, of the patients were better from their headache compared with preoperative scores. The corresponding improvement rates for dizziness were 61.7% (short-term) and 67.9 (long-term). Preoperatively, the mean headache VAS score was 45.6; at short-term follow-up, this was reduced to 25.7, and at long-term follow-up, this further reduced to 24.8. The preoperative mean VAS score for dizziness (35.2) was reduced to 12.2 (short-term) and 13.9 (long-term). The significant postoperative improvement of patient-reported Qol at short-term follow-up remained at long-term follow-up across seven out of eight SF-36 dimensions and three out of four GBI subscale scores. Similar to at short-term follow-up, the Qol improvement is correlated to improvement in headache and/or dizziness.

CONCLUSIONS

The previously reported postoperative, short-term improvement in Qol and complaints appears stable, as the improvement remains at long-term follow-up. This suggests that the beneficial effects of surgical treatment are long-lasting.

Case report: a giant arachnoid cyst masking Alzheimer's disease

BACKGROUND

Intracranial arachnoid cysts are usually benign congenital findings of neuroimaging modalities, sometimes however, leading to focal neurological and psychiatric comorbidities. Whether primarily clinically silent cysts may become causally involved in cognitive decline in old age is neither well examined nor understood.

CASE PRESENTATION

A 66-year old caucasian man presenting with a giant left-hemispheric frontotemporal cyst without progression of size, presented with slowly progressive cognitive decline. Neuropsychological assessment revealed an amnestic mild cognitive impairment (MCI) without further neurological or psychiatric symptoms. The patient showed mild medio-temporal lobe atrophy on structural MRI. Diffusion tensor and functional magnetic resonance imaging depicted a rather sustained function of the strongly suppressed left hemisphere. Amyloid-PET imaging was positive for increased amyloid burden and he was homozygous for the APOEε3-gene. A diagnosis of MCI due to Alzheimer's disease was given and a co-morbidity with a silent arachnoid cyst was assumed. To investigate, if a potentially reduced CSF flow due to the giant arachnoid cyst contributed to the early manifestation of AD, we reviewed 15 case series of subjects with frontotemporal arachnoid cysts and cognitive decline. However, no increased manifestation of neurodegenerative disorders was reported.

CONCLUSIONS

With this case report, we illustrate the necessity of a systematic work-up for neurodegenerative disorders in patients with arachnoid cysts and emerging cognitive decline. We finally propose a modus operandi for the stratification and management of patients with arachnoid cysts potentially susceptive for cognitive dysfunction.

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

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

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.

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.

A Lesion-Proof Brain? Multidimensional Sensorimotor, Cognitive, and Socio-Affective Preservation Despite Extensive Damage in a Stroke Patient

In this study, we report an unusual case of mutidimensional sensorimotor, cognitive, and socio-affective preservation in an adult with extensive, acquired bilateral brain damage. At age 43, patient CG sustained a cerebral hemorrhage and a few months later, she suffered a second (ischemic) stroke. As a result, she exhibited extensive damage of the right hemisphere (including frontal, temporal, parietal, and occipital regions), left Sylvian and striatal areas, bilateral portions of the insula and the amygdala, and the splenium. However, against all probability, she was unimpaired across a host of cognitive domains, including executive functions, attention, memory, language, sensory perception (e.g., taste recognition and intensity discrimination), emotional processing (e.g., experiencing of positive and negative emotions), and social cognition skills (prosody recognition, theory of mind, facial emotion recognition, and emotional evaluation). Her functional integrity was further confirmed through neurological examination and contextualized observation of her performance in real-life tasks. In sum, CG's case resists straightforward classifications, as the extent and distribution of her lesions would typically produce pervasive, multidimensional deficits. We discuss the rarity of this patient against the backdrop of other reports of atypical cognitive preservation, expound the limitations of several potential accounts, and highlight the challenges that the case poses for current theories of brain organization and resilience.

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.

Surgical Decompression of Arachnoid Cysts Leads to Improved Quality of Life: A Prospective Study

BACKGROUND

There is no previous prospective study on the outcome of surgical decompression of intracranial arachnoid cysts (AC).

OBJECTIVE

To investigate if surgical fenestration for AC leads to change in patients' health-related quality of life.

METHODS

Prospective study including 76 adult patients operated for AC. Patients responded to Short Form-36 and Glasgow Benefit Inventory quality of life questionnaires, and to visual analogue scales, assessing headache and dizziness pre- and postoperatively. Patient scores were compared with those of a large sample of healthy individuals.

RESULTS

Preoperatively, 84.2% of the patients experienced headache and 70.1% dizziness. Mean pre- versus postoperative Visual Analogue Scale scores for headache and dizziness dropped from 45.6 to 25.7 and from 35.2 to 12.2, respectively. Preoperative Short Form-36 scores were significantly below age norms in all subscales, but improved after surgery into normal range in 7 out of 8 subscales for middle-aged and older patients. Younger patients' scores remained lower than age norm in 6 out of 8 subscales. A significant postoperative improvement was seen in 3 out of 4 Glasgow Benefit Inventory subscales. Improvement in headache and/or dizziness, but not preoperative cyst size or reduction in cyst volume, correlated with improvement in 6 out of 8 Short Form-36 subscales and 3 out of 4 Glasgow Benefit Inventory subscales. Only 1 patient experienced a severe complication causing permanent invalidity.

CONCLUSION

Surgery for AC can be performed with a fairly low risk of complications and yields significant improvement in quality of life correlated to postoperative improvement in headache and dizziness. These findings may justify a more liberal approach to surgical treatment for AC.

Disequilibrium in patients with posterior fossa arachnoid cysts

BACKGROUND

Arachnoid cysts (AC) are benign, congenital malformations of the leptomeninges. In our experience, dizziness and vertigo are common complaints in patients with such cysts.

OBJECTIVE

To quantify dizziness and imbalance in patients with arachnoid cysts in the posterior fossa using the Dizziness Handicap Inventory (DHI), Vertigo Symptom Scale Short-Form (VSS-SF) and Computerized Dynamic Posturography (CDP). We also wanted to investigate whether any dizziness and imbalance are reversible after surgical cyst decompression.

METHODS

The study includes four patients with AC in the posterior fossa (two in the cerebellopontine angle and two supracerebellar in the midline) and 15 control subjects undergoing ENT surgery for benign lesions of the larynx (n = 10) or the parotid glands (n = 5). All participants answered the DHI and VSS-SF and underwent CDP the day before, and at follow-up after surgery. The AC patients also graded their dizziness through the use of a Visual Analogue Scale (VAS).

RESULTS

Preoperatively, cyst patients scored higher than controls on subjective symptoms (DHI, VSS-SF A and VSS-SF V) and had a lower score on postural sway (CDP). Symptom scores decreased after surgery; the cyst patients improved in the subjective tests (DHI, VAS and VSS-SF), and three of the patients improved their CDP scores. In the controls, symptom and CDP scores were unchanged after surgery.

CONCLUSION

Patients with fossa posterior cyst had a significant preoperative impairment compared with the controls, and they exhibited post-operative improvement in their subjective dizziness.

Incidental findings on brain and spine imaging in children

In recent years, the utilization of diagnostic imaging of the brain and spine in children has increased dramatically, leading to a corresponding increase in the detection of incidental findings of the central nervous system. Patients with unexpected findings on imaging are often referred for subspecialty evaluation. Even with rational use of diagnostic imaging and subspecialty consultation, the diagnostic process will always generate unexpected findings that must be explained and managed. Familiarity with the most common findings that are discovered incidentally on diagnostic imaging of the brain and spine will assist the pediatrician in providing counseling to families and in making recommendations in conjunction with a neurosurgeon, when needed, regarding additional treatments and prognosis.

Pre- and post-operative dizziness and postural instability in temporal arachnoid cyst patients

OBJECTIVES

Arachnoid cysts (AC) are benign, congenital malformations of the leptomeninges, with a predilection for the temporal fossa. In our clinical experience, patients with temporal AC often complain of dizziness and imbalance. However, these symptoms and the effect of surgery on them have not been studied before.

MATERIALS AND METHODS

Dizziness and imbalance in patients with temporal AC were quantified before and after surgical cyst decompression, using the Dizziness Handicap Inventory (DHI), Vertigo Symptom Scale - Short-Form (VSS-SF) and computerized dynamic posturography (CDP). The study includes 16 patients with temporal AC and 15 control subjects undergoing surgery for benign lesions of the larynx (n = 10) or the parotid glands (n = 5). All participants answered the DHI and VSS-SF and underwent CDP the day before and 3-6 months after surgery. The patients with AC also graded their dizziness through the use of a visual analogue scale (VAS).

RESULTS

Preoperatively, cyst patients scored higher than controls on subjective symptoms (DHI, VSS-SF A and VSS-SF V), but not on postural sway (CDP). Symptom scores decreased after surgery; the cyst patients improved significantly in the subjective tests (DHI, VAS and VSS-SF), while CDP scores did not. In the controls, symptom and CDP scores were unchanged after surgery.

CONCLUSIONS

Patients with temporal AC have a significant preoperative impairment and post-operative improvement in their subjective dizziness, but not in postural sway as measured by CDP.

A schizophrenia-like psychotic disorder secondary to an arachnoid cyst remitted with neurosurgical treatment of the cyst

We describe a case of delusional psychosis that was terminated by neurosurgical removal of a large arachnoid cyst. The patient was suffering his first psychotic episode and had symptoms typical of schizophrenia.

The case underscores the importance of considering that an arachnoid cyst can induce psychopathological symptoms, even those of schizophrenia. Indeed, such symptoms may be the cyst's only clinical manifestation.

In addition, the case highlights the importance of doing a structural imaging test when confronted with a first episode of psychosis, especially if the episode is relatively late in appearance. Such imaging may lead to a diagnosis that in turn can enable a definitive neurosurgical resolution of the psychosis.

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.

Intracranial arachnoid cysts: impairment of higher cognitive functions and postoperative improvement

Background

Intracranial arachnoid cysts have been shown to yield cognitive impairment over a range of basic mental functions, and these functions normalize after surgical cyst decompression. We wanted to investigate whether such cysts may also impair executive cognitive functions, and whether surgical cyst decompression leads to an improvement.

Methods

This study included 22 patients with arachnoid cysts and 13 control patients scheduled for low back surgery. All subjects were tested with Delis-Kaplan Executive Function System (D-KEFS) tests, assessing executive function 1 day before surgery and a minimum of 3 months after surgery. The data were analyzed according to scaled score computations based on raw scores provided by D-KEFS, adjusted for age, gender, and educational norms.

Results

Preoperatively, the patients with cysts group performed worse than the control group in verbal knowledge, mental flexibility, inhibitory capacity, problem solving, and planning skills. Postoperatively, the patients with cysts group significantly improved performance and were no longer different from the control group in the following subtests: inhibition, inhibition/switching, letter fluency, category switching, and total switching accuracy. The patients with cysts group also significantly improved performance in color naming, category fluency, and in the Tower test, but nevertheless remained impaired at follow-up compared with the control group. The control group did not show a similar improvement, except for the Tower test. Cyst size or postoperative volume reduction did not correlate with cognitive performance or postoperative improvement. Patients with left-sided temporal cysts performed poorer than patients with right-sided cysts on a complex verbal task demanding mental flexibility.

Conclusions

Arachnoid cysts seem to impair not only basic cognition, but also executive functions. Most of this impairment appears to be reversible after surgical cyst decompression. These results may have implications for future preoperative considerations for patients with intracranial arachnoid cysts.

Maze learning in patients with intracranial arachnoid cysts

BACKGROUND

The temporal lobe is of importance for visuospatial orientation. Intracranial arachnoid cysts have a predilection for the temporal fossa, and might therefore affect visuospatial orientation. The aim was to find out whether temporal cysts affect maze learning and if surgical cyst decompression improves maze performance.

METHODS

Forty-five patients with a temporal arachnoid cyst and 17 control patients with cervical disc disease were tested in a labyrinth route in the hospital corridors the day before surgery and at least 3 months postoperatively.

RESULTS

Thirty-five cyst patients (78 %) experienced postoperative improvement of their preoperative complaints. The cyst patients spent significantly longer time than the controls navigating through the maze in the preoperative test, 161 s and 127 s, respectively, but there was no difference in number of errors between the two groups. However, the cyst patients improved significantly in the postoperative test, both with regards to number of errors they made and time spent, contrary to the control patients, whose postoperative performance equalled that of the preoperative test. For the cyst patients, postoperative improvement in the labyrinth test correlated with the clinical outcome-but not the neuroradiological outcome-after the operation.

CONCLUSIONS

Thus, temporal arachnoid cysts may affect visuospatial orientation and learning in a reversible manner.

Prevalence and natural history of arachnoid cysts in adults

Object

Arachnoid cysts are a frequent finding on intracranial imaging. The prevalence and natural history of these cysts in adults are not well defined.

Methods

We retrospectively reviewed the electronic medical records of a consecutive series of adults who underwent brain MRI over a 12-year interval to identify those with arachnoid cysts. The MRI studies were reviewed to confirm the diagnosis. For those patients with arachnoid cysts, we evaluated presenting symptoms, cyst size, and cyst location. Patients with more than 6 months' clinical and imaging follow-up were included in a natural history analysis.

Results

A total of 48,417 patients underwent brain MRI over the study period. Arachnoid cysts were identified in 661 patients (1.4%). Men had a higher prevalence than women (p < 0.0001). Multiple arachnoid cysts occurred in 30 patients. The most common locations were middle fossa (34%), retrocerebellar (33%), and convexity (14%). Middle fossa cysts were predominantly left-sided (70%, p < 0.001). Thirty-five patients were considered symptomatic and 24 underwent surgical treatment. Sellar and suprasellar cysts were more likely to be considered symptomatic (p < 0.0001). Middle fossa cysts were less likely to be considered symptomatic (p = 0.01. The criteria for natural history analysis were met in 203 patients with a total of 213 cysts. After a mean follow-up of 3.8 ± 2.8 years (for this subgroup), 5 cysts (2.3%) increased in size and 2 cysts decreased in size (0.9%). Only 2 patients developed new or worsening symptoms over the follow-up period.

Conclusions

Arachnoid cysts are a common incidental finding on intracranial imaging in all age groups. Although arachnoid cysts are symptomatic in a small number of patients, they are associated with a benign natural history for those presenting without symptoms.

Arachnoid cyst of the velum interpositum originating from tela choroidea

BACKGROUND

Arachnoid cysts originating from the velum interpositum are very rare, and their existence as a clinicopathologic entity remains controversial. We report a case of a patient with an arachnoid cyst of the velum interpositum presenting with memory disturbance, focusing on the anatomical origin of the lesion and the physiological mechanisms causing memory disturbance.

CASE DESCRIPTION

A 65-year-old man with a large cystic lesion in the velum interpositum experienced progressive memory disturbance and enlargement of the lesion 6 months before referral to our institution. Neuropsychological evaluation on admission demonstrated severe memory disturbance. Radiological examination did not reveal hydrocephalus, but the bilateral fornices and thalami were compressed by the cyst. The patient underwent endoscopic cystoventriculostomy via the frontal horn of the right lateral ventricle through a frontal burr hole. Histopathology of the sample was consistent with that of an arachnoid cyst, and the endoscopic findings suggested that the cyst originated from the tela choroidea, which covers the velum interpositum. The symptoms resolved after surgery with significant improvement in neuropsychological test scores.

CONCLUSION

Arachnoid cysts of the velum interpositum are rare but distinct clinicopathologic entities that originate from the tela choroidea. The lesions can cause memory disturbance without hydrocephalus due to compression of the fornices and thalami, but this can be reversed by surgery.

Arachnoid cysts

Arachnoid cysts are fluid-filled duplications or splittings of the arachnoid layer with a content which is similar but not equal to the cerebrospinal fluid. Arachnoid cysts are not actual neurodegenerative disorders, rather the underlying defect of the texture of the arachnoid layer is probably congenital in nature. They can occur sporadically or can be associated with other malformations or diseases. Arachnoid cysts may be discovered in early childhood. However, they can develop de novo, grow or decrease in size. They may be diagnosed by ultrasound screening in the fetal period or be discovered during childhood or adulthood. Many arachnoid cysts are asymptomatic.Treatment strategies are discussed controversially. If they are diagnosed incidentally or are correlated with only very mild symptoms, a conservative management with follow-up imaging may be favored. If they grow, they can cause headaches, seizures or other neurological symptoms and require neurosurgical treatment. This chapter addresses aspects of pathogenesis, clinical symptoms, indication for neurosurgical treatment and treatment options.

Temporo-sylvian arachnoidal cyst and an extreme pneumatization of the cranial sinuses: a case report

We present a patient who showed MRI evidence of a giant temporo-sylvian arachnoidal cyst of the left hemisphere and an extreme pneumatization of the sphenoid and frontal sinuses. No sign of mass effect or cerebral atrophy was detected. This patient presented a deficit of memory and control functions, but quality of life was not affected. Surgery was not performed. Arachnoidal cyst and anatomic variants of the sinus region have not a common etiology. This is the first report that describes a giant temporo-sylvian arachnoidal cyst with anatomic variants of the paranasal sinuses.

Arachnoid cysts do not contain cerebrospinal fluid: A comparative chemical analysis of arachnoid cyst fluid and cerebrospinal fluid in adults

Background

Arachnoid cyst (AC) fluid has not previously been compared with cerebrospinal fluid (CSF) from the same patient. ACs are commonly referred to as containing "CSF-like fluid". The objective of this study was to characterize AC fluid by clinical chemistry and to compare AC fluid to CSF drawn from the same patient. Such comparative analysis can shed further light on the mechanisms for filling and sustaining of ACs.

Methods

Cyst fluid from 15 adult patients with unilateral temporal AC (9 female, 6 male, age 22-77y) was compared with CSF from the same patients by clinical chemical analysis.

Results

AC fluid and CSF had the same osmolarity. There were no significant differences in the concentrations of sodium, potassium, chloride, calcium, magnesium or glucose. We found significant elevated concentration of phosphate in AC fluid (0.39 versus 0.35 mmol/L in CSF; p = 0.02), and significantly reduced concentrations of total protein (0.30 versus 0.41 g/L; p = 0.004), of ferritin (7.8 versus 25.5 ug/L; p = 0.001) and of lactate dehydrogenase (17.9 versus 35.6 U/L; p = 0.002) in AC fluid relative to CSF.

Conclusions

AC fluid is not identical to CSF. The differential composition of AC fluid relative to CSF supports secretion or active transport as the mechanism underlying cyst filling. Oncotic pressure gradients or slit-valves as mechanisms for generating fluid in temporal ACs are not supported by these results.

Prevalence and natural history of arachnoid cysts in children

OBJECT

Arachnoid cysts are a frequent finding on intracranial imaging in children. The prevalence and natural history of these cysts are not well defined. The authors studied a large consecutive series of children undergoing MR imaging to better define both the MR imaging-demonstrated prevalence and behavior of these lesions over time.

METHODS

The authors reviewed a consecutive series of 11,738 patients who were 18 years of age or younger and had undergone brain MR imaging at a single institution during an 11-year period. In the patients in whom intracranial arachnoid cysts were identified, clinical and demographic information was recorded and imaging characteristics, such as cyst size and location, were evaluated. Prevalence data were analyzed using univariate and multivariate logistic regression, linear regression, and ANOVA. All patients with sufficient data (repeat MR imaging studies as well as repeated clinical evaluation over at least 5 months) for a natural history analysis were identified. This group was assessed for any change in symptoms or imaging appearance during the follow-up interval.

RESULTS

Three hundred nine arachnoid cysts (2.6% prevalence rate) were identified. There was an increased prevalence of arachnoid cysts in males (p < 0.000001). One hundred eleven patients met all criteria for inclusion in the natural history analysis. After a mean follow-up of 3.5 years, 11 arachnoid cysts increased in size, 13 decreased, and 87 remained stable. A younger age at presentation was significantly associated with cyst enlargement (p = 0.001) and the need for surgery (p = 0.05). No patient older than 4 years of age at the time of initial diagnosis had cyst enlargement, demonstrated new symptoms, or underwent surgical treatment.

CONCLUSIONS

Arachnoid cysts are a common incidental finding on intracranial imaging in pediatric patients. An older age at the time of presentation is associated with a lack of clinical or imaging changes over time.

Microarray-based gene expression profiling and DNA copy number variation analysis of temporal fossa arachnoid cysts

BACKGROUND

Intracranial arachnoid cysts (AC) are membranous sacs filled with CSF-like fluid that are commonly found in the temporal fossa. The majority of ACs are congenital. Typical symptoms are headache, dizziness, and dyscognition. Little is known about genes that contribute to the formation of the cyst membranes.

METHODS

In order to identify differences in gene expression between normal arachnoid membrane (AM) and cyst membrane, we have performed a high-resolution mRNA microarray analysis. In addition we have screened DNA from AC samples for chromosomal duplications or deletions using DNA microarray-based copy number variation analysis.

RESULTS

The transcriptome consisting of 33096 gene probes showed a near-complete similarity in expression between AC and AM samples. Only nine genes differed in expression between the two tissues: ASGR1, DPEP2, SOX9, SHROOM3, A2BP1, ATP10D, TRIML1, NMU were down regulated, whereas BEND5 was up regulated in the AC samples. Three of the AC samples had unreported human DNA copy number variations, all DNA gains.

CONCLUSIONS

Extending results of previous anatomical studies, the present study has identified a small subset of differentially expressed genes and DNA alterations in arachnoid cysts compared to normal arachnoid membrane.

Neurocognitive and psychological profiles in pediatric arachnoid cyst

OBJECTIVE

This study aims to investigate whether intracranial arachnoid cysts (AC) compromise neurocognitive function and psychological profiles in pediatric patients, depending on various clinical factors.

METHODS

We assessed neurocognitive functions and psychological tests in 35 AC patients and 35 healthy control subjects between October 2007 and April 2008. AC patients ranged in age from 3 to 15 (7.94 +/- 3.12) years old and control patients from 5 to 13 (8.84 +/- 2.17) years old. The location of the AC were temporal (n = 22), frontal (n = 6), suprasellar (n = 4), and posterior fossa (n = 3). Patients underwent neurocognitive and psychological assessments before surgery. To investigate which AC impair neurocognitive function and psychological profile, we assessed intelligence, memory, attention, executive function, behavioral problems, emotional distress, and parenting stress.

RESULTS

AC caused some demonstrated impairment by both neurocognitive function and psychological assessments. Left hemisphere AC tended to have more anxiety; mood changes can be detected depending on cyst grade. An incidental finding of AC after trauma is more intelligent, well-reserved executive function. Frontal locations tended to cause more anxiety than temporal locations.

CONCLUSIONS

Our results imply that intracranial AC impairs some neurocognitive and psychological functions. An incidental finding of AC after trauma was a more intelligent, well-reserved executive function. AC in the left hemisphere, frontal location tended to cause more anxiety. The AC itself did not cause differences in neurocognitive function from the control group. However, parenting stress in the AC group was much higher than in the control group.