Arachnoid cysts: how do postsurgical cyst size and seizure outcome correlate?

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

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

Intracranial cysts: incidental or neurodevelopmental?

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Intracranial arachnoid cysts and epilepsy in children: Should this be treated surgically? Our 29-year experience and review of the literature

INTRODUCTION AND OBJECTIVE

Arachnoid cysts (ACs) are relatively frequent lesions related to different neurological symptoms, being mostly incidentally diagnosed. This study aims to clarify whether AC surgery in epileptic patients is useful in their treatment.

MATERIAL AND METHODS

The patients registered in the database of the Neuropediatrics Section from May 1990 to August 2019 are analyzed retrospectively. Patients in whom the diagnosis of ACs and epilepsy coincide are studied. The location, size and number of ACs, neurological development, age at diagnosis, follow-up time, the performance of surgery on the cyst, evolution, anatomical relationship between brain electrical activity and location of AC, and type of epilepsy are analyzed.

RESULTS

After analyzing the database, we found 1881 patients diagnosed with epilepsy, of which 25 had at least one intracranial AC. In 9 of the patients, cerebral or genetic pathologies were the cause of epilepsy. Of the other 16, only 2 patients showed that the type of epilepsy and the epileptogenic focus coincided with the location of the AC; one of them was surgically treated without success, and the other one remained asymptomatic without receiving medical or surgical treatment.

CONCLUSIONS

Although it is necessary to design a prospective study to establish causality, the results of our research and the available literature suggest that there is no causal relationship between the presence of ACs and epilepsy. The study and treatment of these patients should be carried out in a multidisciplinary epilepsy surgery unit, without initially assuming that the AC is the cause of epilepsy.

Intracranial arachnoid cysts and epilepsy in children: Should this be treated surgically? Our 29-year experience and review of the literature

INTRODUCTION AND OBJECTIVE

Arachnoid cysts (ACs) are relatively frequent lesions related to different neurological symptoms, being mostly incidentally diagnosed. This study aims to clarify whether AC surgery in epileptic patients is useful in their treatment.

MATERIAL AND METHODS

The patients registered in the database of the Neuropediatrics Section from May 1990 to August 2019 are analyzed retrospectively. Patients in whom the diagnosis of ACs and epilepsy coincide are studied. The location, size and number of ACs, neurological development, age at diagnosis, follow-up time, the performance of surgery on the cyst, evolution, anatomical relationship between brain electrical activity and location of AC, and type of epilepsy are analyzed.

RESULTS

After analyzing the database, we found 1881 patients diagnosed with epilepsy, of which 25 had at least one intracranial AC. In 9 of the patients, cerebral or genetic pathologies were the cause of epilepsy. Of the other 16, only 2 patients showed that the type of epilepsy and the epileptogenic focus coincided with the location of the AC; one of them was surgically treated without success, and the other one remained asymptomatic without receiving medical or surgical treatment.

CONCLUSIONS

Although it is necessary to design a prospective study to establish causality, the results of our research and the available literature suggest that there is no causal relationship between the presence of ACs and epilepsy. The study and treatment of these patients should be carried out in a multidisciplinary epilepsy surgery unit, without initially assuming that the AC is the cause of epilepsy.

Long-term outcome of large sylvian arachnoid cysts: the role of surgery has been exaggerated

OBJECTIVE

The surgical indications for some arachnoid cysts (ACs) are controversial. While surgical procedures can be effective when an AC is a definite cause of hydrocephalus or papilledema, most ACs do not cause any symptoms or signs. Some surgeons perform several procedures to treat ACs because of their large size. The purpose of this study was to compare the long-term outcomes of Galassi type III ACs between surgery and nonsurgery groups.

METHODS

The medical records of 60 patients diagnosed with sylvian ACs (Galassi type III) who visited Seoul National University Children's Hospital from July 1990 to March 2018 were analyzed. The authors compared the outcomes between those treated with surgery and those not treated with surgery.

RESULTS

Of the 60 patients, 27 patients had no symptoms, 19 patients had vague symptoms and signs associated with ACs, and the remaining 14 patients had definite AC-related symptoms and signs. Thirty-eight patients underwent surgery, and 22 patients underwent observation. Some operations were accompanied by complications. Among the 33 patients in the surgery group, excluding 5 with hydrocephalus or papilledema, 8 patients needed 18 additional operations. However, there were no patients in the nonsurgery group who needed surgical intervention during the follow-up period (mean 67.5 months), although the size of the AC increased in 2 patients. Changes in AC size were not correlated with symptom relief.

CONCLUSIONS

When patients with hydrocephalus or papilledema were excluded, there was no difference in the outcomes between the surgery and nonsurgery groups regardless of the size of the sylvian AC. Surgeons should be cautious when deciding whether to operate.

The association of arachnoid cysts and focal epilepsy: Hospital based case control study

OBJECTIVE

Arachnoid cysts (ACs) are common findings in brain MRI. Our aim was to examine frequency and distribution of ACs in patients with focal epilepsy, compared to healthy control subjects, and to investigate the association of AC and electro-clinical features of focal epilepsy.

PATIENTS AND METHODS

We performed a retrospective case-control study, using data from 180 patients that underwent video-EEG monitoring between 2009 and 2012, and of 114 healthy controlled subjects. Analysis of electro-clinical data and structural MRI images was conducted.

RESULTS

A significantly higher proportion of ACs in the focal epilepsy group (19/180; 10.5%) compared to healthy control subjects (3/114; 2.6%) (p=0.012) was identified. Significant congruence of semiological features or interictal and ictal EEG with AC localization was identified in only one MRI nonlesional patient with temporal cyst localization.

CONCLUSION

ACs are seen more often in patients with focal epilepsy. Explicit association between focal epilepsy and AC is possible but exceptional. More likely, focal epilepsy and AC share a common etiological ancestor but represent distant and distinct entities.

Hemorrhagic infarction following open fenestration of a large intracranial arachnoid cyst in a pediatric patient

Intracranial arachnoid cysts are a rare condition thought to be congenital in nature. Treatment of intracranial arachnoid cysts remains controversial based on their variable presentation. Treatment options include CSF shunting, endoscopic fenestration, or craniotomy and open fenestration for larger cysts. The complications of these procedures can include hydrocephalus, subdural hematomas, hygromas, and--more rarely--intraparenchymal hemorrhage. The authors found very few reports of hemorrhagic infarction as a complication of arachnoid cyst fenestration in the literature. The authors report a case of an 18-year-old female patient who suffered an ipsilateral hemorrhagic infarction after craniotomy for open fenestration of an arachnoid cyst.

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 Cysts Containing Cerebrospinal Fluid-Like Fluid: Results of Endoscopic Neurosurgery in a Series of 64 Consecutive Cases

BACKGROUND:

Intracranial cysts containing cerebrospinal fluid (CSF) may be developmental or acquired.

OBJECTIVE:

To analyze the results of endoscopic neurosurgery in the management of intracranial CSF cysts.

METHODS:

In a 7-year period, 64 consecutive patients underwent endoscopic neurosurgery for CSF cysts. Group 1 consisted of 13 patients with acquired cysts; group 2 included 51 patients with developmental cysts. In all cases, the cyst walls were fenestrated through small burr holes with frameless guided operative endoscopes. Follow-up ranged from 1 to 6 years (mean, 3.4 years).

RESULTS:

There were no mortality and no permanent morbidity, apart from a patient (1.6%) who remained neurologically intact but required ventriculoperitoneal shunting because of intraoperative hemorrhage. The planned fenestrations could be performed in all patients except 2, owing to thick, opaque cyst walls. In group 1, 6 patients fully recovered and remained intact throughout the follow-up, whereas 7 improved but had various degrees of neurological disabilities that were related to their initial diseases. Radiological results were excellent in all cases. In group 2, there were 7 asymptomatic patients who remained unchanged and 44 “symptomatic” patients: 40 (91%) clinically improved, 4 (9%) remained unchanged, and none worsened. Cyst size decreased in 37 patients (74%) and remained unchanged in 13 (26%).

CONCLUSION:

In this series, patients of different ages, harboring cysts of various sizes and locations, could be satisfactorily treated with endoscopic neurosurgery.

Shunting for the Treatment of Arachnoid Cysts in Children

BACKGROUND:

The optimal treatment of symptomatic arachnoid cysts remains controversial.

OBJECTIVE:

We present a single-institution experience on surgical treatment of arachnoid cysts.

METHODS:

Between January 1983 and January 2008, 92 patients with symptomatic arachnoid cysts underwent surgery at our institute. All patients were evaluated with CT and/or MRI and were operated upon and had regular follow-up examinations.

RESULTS:

There were 60 males and 32 females. The mean age was 3.6 years (range, 2 days to 14 years). Forty-eight cysts (52%) were within the sylvian fissure, 16 (17%) were in the cerebral convexity, 15 (16%) were infratentorial, 10 (11%) were in the interhemispheric fissure, and 3 (4%) were parasellar. Cystoperitoneal shunt was placed in 67 (73%) patients; ventricular drainage alone was performed in 14 (15%) patients; and combined drainage of the ventricular system and cyst, using a 3-way connector, was performed in 8 (9%) patients. Craniotomy and fenestration of the cyst was performed in 2 (2%) patients, whereas total excision of the cyst was performed in 1 patient. Shunt revision for various reasons was performed in 34 patients (39%), whereas 13 (14%) patients required more than one revision. Complete alleviation of symptoms was achieved in all patients after treatment, regardless of cyst reduction. After a mean follow-up of 8.5 years no further enlargement of the arachnoid cysts was noted.

CONCLUSION:

Shunt placement is a safe and effective surgical treatment of symptomatic arachnoid cysts in children. Cyst reduction is greater in children younger than 2 years of age.

Sylvian fissure arachnoid cysts: a survey on their diagnostic workout and practical management

BACKGROUND

The management of Sylvian arachnoid cysts in children is still a matter of debate. Diagnosis is often incidental, and symptoms are frequently aspecific in symptomatic cases. Suggested diagnostic investigation results have been often unclear. Surgical treatment is also controversial, pure, and assisted endoscopic cyst marsupialization having entered in the traditional debate between craniotomic and shunting approach

PURPOSE

The objective of the present study was to survey if (and, eventually, which) agreement points do actually exist between internationally recognized pediatric neurosurgery centers in the management of children with a controversial type of Sylvian arachnoid cyst (Type II cyst).

METHODS

Contributors were asked to answer to a six-separate-part multiple choice questionnaire related to the case of a 2.7-year-old boy with a Type II left Sylvian arachnoid cyst presented in different clinical situations. If surgery was indicated, it was asked which surgical procedure the authors would have suggested as first option.

RESULTS AND CONCLUSIONS

The option of the mere clinical observation was chosen by the majority of surgeons in case of asymptomatic clinical discovery. On the other hand, a constantly high percentage of participants suggested direct surgical treatment based on clinical manifestations or as a preventive measure justified by the risk of spontaneous or traumatic intracranial bleeding. The only diagnostic investigation result which significantly influenced the surgical indication was a localizing electroencephalography, if the child presented with seizures. The result is that in most cases the surgical indication was based on aspecific clinical manifestations and laboratory data. Craniotomy and arachnoid cyst marsupialization represented the preferred surgical option (66.6%), 28.8% of the participants suggesting pure or assisted endoscopic cyst marsupialization as primary surgical procedure. Cyst shunting was suggested by only three centers.

A population based study of intracranial arachnoid cysts: clinical and neuroimaging outcomes following surgical cyst decompression in adults

BACKGROUND

We have gradually adopted a liberal attitude towards surgical decompression of arachnoid cysts. This study describes the results from our institution.

METHODS

Long term clinical and neuroimaging results of 156 adult patients (aged > or = 16 years) operated on for arachnoid cysts in our department during the period January 1987 to September 2004 were assessed based on their medical and neuroimaging records, and on a questionnaire.

RESULTS

The clinical and/or neuroimaging results indicated that the cyst was successfully decompressed in all patients. 82% of patients were asymptomatic or had insignificant complaints at follow-up. 12% reported no symptom relief whereas 6% experienced worsening of symptoms. The cyst disappeared after surgery, or was reduced to < 50% of the preoperative volume, in 66% of cases. In another 24%, the postoperative volume was also reduced, but was larger than 50% of the original cyst volume. No reduction in fluid volume was observed in 10% of cases. There was no association between volume reduction and clinical improvement. A complication occurred in 26 patients (17%), all with temporal cysts, leading to reoperation in 11 patients (7.1%). In only two patients did the complication cause a permanent slight disability.

CONCLUSION

Decompression of arachnoid cysts yields a substantial clinical benefit with a low risk of severe complications.

A population-based study of intracranial arachnoid cysts: clinical and neuroimaging outcomes following surgical cyst decompression in children

OBJECT

If, when, and how children with arachnoid cysts should undergo surgery has been a matter of debate. In the present study the authors describe long-term clinical and neuroimaging results in children with intracranial arachnoid cysts, treated in accordance with the authors' policy of performing surgery in most of these cases.

METHODS

The study included 48 pediatric patients (age < 16 years of age) who underwent surgery for treatment of an arachnoid cyst at Haukeland University Hospital between January 1987 and September 2004. Forty-one patients underwent cyst fenestration to the basal cisterns and posterior fossa. Long-term results were assessed retrospectively on the basis of medical and neuroimaging records. Additional information was obtained by means of a check-box questionnaire completed by the patients and their parents. At their follow-up examinations, 82% of the patients had no or insignificant complaints, 14% reported no improvement, and 4% noted a worsening of symptoms. In 56% of the patients with appropriate imaging for analysis, the cyst was no longer visible on neuroimaging studies. In 23%, the postoperative fluid volume was reduced to less than 50% of the original cyst volume, and in another 19%, the volume was reduced but was larger than 50% of the original. The cyst was unchanged in only 2%. There was a significant association between a volume reduction greater than 50% and clinical improvement. Three patients (6%), all with temporal cysts, had minor complications that led to additional surgery in one patient. No complications caused permanent disability. Eight patients (17%) underwent additional surgery due to suspected or demonstrated treatment failure.

CONCLUSIONS

Most children who underwent cyst fenestration via a craniotomy experienced a good long-term outcome with no severe complications.

Placement of subdural electrode grids for seizure focus localization in patients with a large arachnoid cyst. Technical note

Subdural electrode arrays are placed to localize seizure foci for possible resection. The procedure is usually straightforward when an electrode grid array is placed on the brain convexity but can become complicated if the surface on which the grids are applied is not convex. Arachnoid cysts can be associated with seizures, but their topography presents a challenge to standard techniques for the placement of subdural grids. The authors report on a technique for electrode grid placement that successfully localized seizure foci in the depths of arachnoid cysts in two patients. Subdural grids were placed to conform to the concave cyst cavity. They were held in place with rolled gelatin foam padding, which filled the arachnoid cyst. The padding was removed before removing the electrode grids and resecting the seizure focus. Although arachnoid cysts present a technical challenge when seizure foci are located within the cyst cavity, the technique of packing the cyst cavity with gelatin foam provides good electrode contact on the concave cyst wall, allowing adequate seizure focus localization.

A population-based study of intracranial arachnoid cysts: clinical and neuroimaging outcomes following surgical cyst decompression in children

Object

If, when, and how children with arachnoid cysts should undergo surgery has been a matter of debate. In the present study the authors describe long-term clinical and neuroimaging results in children with intracranial arachnoid cysts, treated in accordance with the authors' policy of performing surgery in most of these cases.

Methods

The study included 48 pediatric patients (age < 16 years of age) who underwent surgery for treatment of an arachnoid cyst at Haukeland University Hospital between January 1987 and September 2004. Forty-one patients underwent cyst fenestration to the basal cisterns and posterior fossa. Long-term results were assessed retrospectively on the basis of medical and neuroimaging records. Additional information was obtained by means of a check-box questionnaire completed by the patients and their parents.

At their follow-up examinations, 82% of the patients had no or insignificant complaints, 14% reported no improvement, and 4% noted a worsening of symptoms. In 56% of the patients with appropriate imaging for analysis, the cyst was no longer visible on neuroimaging studies. In 23%, the postoperative fluid volume was reduced to less than 50% of the original cyst volume, and in another 19%, the volume was reduced but was larger than 50% of the original. The cyst was unchanged in only 2%. There was a significant association between a volume reduction greater than 50% and clinical improvement. Three patients (6%), all with temporal cysts, had minor complications that led to additional surgery in one patient. No complications caused permanent disability. Eight patients (17%) underwent additional surgery due to suspected or demonstrated treatment failure.

Conclusions

Most children who underwent cyst fenestration via a craniotomy experienced a good long-term outcome with no severe complications.

Arachnoid cysts in adults: long-term follow-up of patients treated with internal shunts to the subdural compartment

BACKGROUND

We have previously presented an alternative method for surgical decompression of intracranial arachnoid cysts. This minimally invasive method, with insertion of an internal shunt from the cyst to the subdural compartment, seemed to be an efficient and simple, and hence promising technique. The aim of the present study was to investigate the long-term results of this procedure.

METHODS

This study is a questionnaire-based retrospective study that includes 31 adult patients (>18 years) who were operated on in our department for an arachnoid cyst in the temporal fossa or overlying the frontal convexity with the internal shunt technique between April 1990 and October 2003. Follow-up ranged from 15 months to 14.8 years (mean = 8.2 years).

RESULTS

Of the patients, 83% were asymptomatic or had insignificant complaints at follow-up. A total of 17% reported no reduction of the preoperative complaints. No patient experienced worsening of the symptoms. The cyst was no longer visible on postoperative radiologic examinations in 37% of the patients. In 37%, the postoperative fluid volume was less than 50% of the original volume. In 13%, the cyst volume was reduced but the postoperative volume was greater than 50% of the original cyst volume. Thus, the cyst was unchanged in only 13% of the patients. There was no correlation between volume reduction and clinical improvement. A complication (subdural hygroma or hematoma) occurred in 7 patients, all with temporal cysts, leading to reoperation in 4. None of the complications caused permanent neurologic deficits or invalidity. Seven patients were reoperated on because of suspected or established treatment failure.

CONCLUSIONS

The internal shunt technique is a relatively simple, safe, and efficient alternative method for treatment of arachnoid cysts. It should be considered a valuable alternative in the treatment of arachnoid cysts.

Evidence against association between arachnoid cysts and epilepsy

Arachnoid cysts are often discovered incidentally in MRs performed for a variety of reasons. In this study, we have attempted to determine a possible relationship between the arachnoid cyst, seizure type and EEG abnormalities. Eight patients were classified according to the Classification of Epilepsies and Epileptic Syndromes of ILAE as idiopathic generalized or localized epilepsy: three as idiopathic generalized epilepsy, three as Rolandic epilepsy and two as juvenile myoclonic epilepsy. Two patients with rare nocturnal seizures had normal EEGs in the awaking and sleep stage. The EEGs of five patients with simple or complex partial seizures revealed focal epileptiform abnormalities, but only one patient had the same location with the arachnoid cyst. Five patients with symptomatic epilepsy had diffuse slowing in their EEGs and only one patient had seizure focus in the EEG that was contralateral to the arachnoid cyst. According to our study, seizure type and EEG abnormality corresponds to arachnoid cyst location in only one patient. Therefore, we suggest that arachnoid cysts may not be related to a specific seizure type and EEG focus.

Intracranial arachnoid cysts in children: a review of pathogenesis, clinical features, and management

Arachnoid cysts are developmental anomalies that are most often diagnosed in childhood. They are often discovered as incidental findings found on imaging. Occasionally they may produce symptoms because of expansion or bleeding. There may be underlying maldevelopment of the cortex especially the temporal lobe. There is controversy regarding the role and the type of surgery indicated in its treatment. Recent descriptions of aphasia and attention-deficit disorders associated with these cysts indicate that we do not fully understand this entity. There is also no acceptable explanation for the male preponderance and increased incidence on the left side. The distribution, clinical features, treatment modalities, and some unusual syndromes associated with arachnoid cysts in children are discussed in this review.

Temporal lobe epilepsy associated with hippocampal sclerosis and a contralateral middle fossa arachnoid cyst

We report on a 13-year-old boy with temporal lobe epilepsy associated with left hippocampal sclerosis and a contralateral arachnoid cyst in the middle cranial fossa (ACMCF). Chronic intracranial recording from subdural grid electrodes showed the left medial temporal lobe to be the ictal onset zone. After left anterior temporal lobectomy with hippocampectomy, seizure control was improved. ACMCF was not considered the direct cause of epilepsy; instead the seizures were attributed to hippocampal sclerosis.