The contribution of prenatal diagnosis to the understanding of malformative intracranial cysts: state of the art

Staged neurosurgical approach for giant and progressive neonatal arachnoid cysts: a case series and review of the literature

OBJECTIVES

Prenatally diagnosed complex arachnoid cysts are very rare. While the true prenatal incidence is still unknown, they account for approximately 1% of intracranial masses in newborns. They rarely exhibit rapid growth or cause obstructive hydrocephalus, but if they increase to such a dimension during pregnancy, the ideal management is not well established. We present our detailed perinatal experience, covering prenatal diagnosis, a compassionate delivery process, and neonatal stabilization. Finally, a thorough postnatal neurosurgical intervention was performed. Initially, our focus was on the gradual reduction of cyst size as a primary effort, followed by subsequent definitive surgical treatment.

METHODS

This case series shows the treatment course of three fetuses with antenatally diagnosed large arachnoid cysts. We present pre- and postnatal management and imaging, as well as the surgical treatment plan and the available clinical course during follow-up.

RESULTS

Two girls and one boy were included in the current review. All three cases presented with prenatally diagnosed complex arachnoid cysts that increased in size during pregnancy. The mean gestational age at delivery was 35 weeks (range 32 to 37 weeks), and all patients were delivered by a caesarian section. Increasing head circumference and compression of brain structures were indications for delivery, as they are associated with a high risk of excess intracranial pressures and CSF diapedesis, as well as traumatic delivery and maternal complications. All cysts were supratentorial in location; one expanded into the posterior fossa, and one was a multicompartment cyst. All children underwent an initial surgical procedure within the first days of life. To relieve cyst pressure and achieve a reduction in head circumference, an ultrasound-guided or endoscopic-assisted internal shunt with drainage of the cyst to the ventricles or subdural/subarachnoid space was inserted. Definite surgical therapy consisted of cyst marsupialization and/or cysto-peritoneal shunt implantation. All children survived without severe neurodevelopmental impairments.

CONCLUSION

With the cases presented, we demonstrate that the slow reduction of immense cyst size as an initial procedure until optimal requirements for final surgical treatment were achieved has proven to be optimal for neurological outcome. Special emphasis has to be taken on the delicate nature of premature newborn babies, and surgical steps have to be thoroughly considered within the interdisciplinary team.

Coexistence of Trigonocephaly and Sylvian Arachnoid Cysts: A Coincidence?

INTRODUCTION

The association between trigonocephaly and Sylvian fissure arachnoid cysts (ACs) has been occasionally reported in the literature. However, the real incidence of this association and its clinical relevance remain unknown.

METHODS

The authors collected and retrospectively reviewed all clinical charts and CT scans of patients surgically treated for trigonocephaly at the Pediatric Neurosurgical Department of Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS from January 2014 to June 2023.

RESULTS

During the study period, 136 patients with trigonocephaly underwent surgery. Analysis of the clinical charts revealed that in 39.7% of the cases (54/136), preoperative CT scan depicted the presence of a Sylvian fissure AC. Of these, AC was bilateral in 23 cases and unilateral in the remaining 31. All unilateral ACs were on the left side. The ACs were classified as Galassi grade I in 52 cases (96.3%) and Galassi grade II in 2 cases (3.7%). Interestingly, in 1 case we reported a Galassi grade I AC enlargement during follow-up, thereby necessitating surgical fenestration.

CONCLUSION

ACs and trigonocephaly are well-known conditions for pediatric neurosurgeons; however, their association is poorly defined. Despite the lack of reports on the incidence and clinical significance of this association, it is worth knowing that radiological follow-up is essential in monitoring AC evolution.

Prenatal dispositions and genetic analysis of monozygotic female twins with suprasellar cysts and hydrocephalus: A case report

INTRODUCTION

We present a unique case of monozygotic female twins with virtually identical clinical and radiological presentations of supratentorial hydrocephalus and cystic formations from the suprasellar cistern.

DISCUSSION

Evaluating genetic predispositions and prenatal exposures is crucial for hydrocephalus in twins. Familial cases imply a genetic contribution to the development of these anomalies, including chromosomal abnormalities and specific variants linked to arachnoid cyst formation in various syndromes. Extensive genetic analyses found no pathogenic variants in the twins. Prenatal exposure to anti-epileptic medication was known during pregnancy and may be associated with fetal abnormalities, but not central nervous system (CNS) malformations, and was therefore not considered the cause of the condition in the twins. The twins presenting simultaneously with hydrocephalus caused by suprasellar cysts (SAC) underwent a two-step surgical management: initial ventriculoperitoneal shunt (VPS) placement followed by fenestration. Postoperative imaging showed cyst reduction, but a secondary VPS was necessary in both cases.

CONCLUSION

Genetic analysis is less likely to identify a monogenic etiology in non-syndromic cases of SACs, which are assumed to be multifactorial. There is no established evidence linking a teratogenic effect of anti-epileptic drugs to CNS malformations. Moreover, the surgical treatment of this complex condition constitutes a point of discussion.

Prenatal diagnosis of arachnoid cysts: MRI features and neurodevelopmental outcome

OBJECTIVE

Arachnoid cysts (AC) are congenital lesions comprising 1% of all intracranial mass lesions. The aim of this study was to characterize arachnoid cysts and their neurodevelopmental outcome and to compare it with the outcome of children without AC.

METHODS

This is a retrospective cohort study of arachnoid cysts detected prenatally by fetal MRI in 29 fetuses compared to a control group of 59 fetuses without arachnoid cyst who were examined by MRI. The cohort was investigated from two different angles: anatomical and developmental. Anatomical analyzation, the cohort was divided into 2 groups by the arachnoid cyst anatomical location: group A (n = 9), which included cases with supratentorial cyst, and group B (n = 20), which included cases with infratentorial cyst. Developmental analyzation, the cohort was divided into 2 groups by the neurodevelopmental outcome: group γ (n = 5) which included cases that were affected by arachnoid cyst presence, and group δ (n = 17) which included cases that had neurodevelopmental outcome within the normal range. Data collected included prenatal history, MRI features, sonographic follow up, and neurodevelopmental outcome.

RESULTS

In 22/29 cases we achieved a long-term follow up, by evaluation of children development in a range of ages from 6 months to 6 years. In group A (n = 9), 4 infants had normal outcome, 2 had abnormal outcome, 1 pregnancy was terminated, and 2 cases were not cooperative with the study. In group B (n = 20), 13 infants had normal outcome, 3 had abnormal outcome, and 4 cases were not cooperative with the study.

CONCLUSIONS

From all cases with AC detected by fetal MRI, 77.3% had normal neurodevelopmental outcome and 22.7% had abnormal neurodevelopment.

Nerve-Sheath-Risen Neuroglial Cyst: A Case Report and Review of the Literature

BACKGROUND

Neuroglial cysts are rare intracranial lesions that are believed to originate from the sequestration of neural tube lining during embryogenesis. They can present anywhere within the neuraxis; however, their most common location is the frontal lobe. Cerebellopontine angle (CPA) neuroglial cysts are extremely rare and to the best of authors' knowledge, there are no previous reports of a neuroglial cyst arising from cranial nerves.

CASE DESCRIPTION

The current study presented a male adolescent with the reoccurrence of an intracranial cyst with symptoms of diplopia and facial numbness primarily treated as CPA arachnoid cyst with fenestration of the cyst 12 months prior to admission to our center. Different magnetic resonance imaging (MRI) sequences showed a thin-walled extra-axial cyst at the right CPA without gadolinium (Gd)-enhancement. Direct visualization of the lesion revealed a cyst arising from the 5th cranial nerve sheath compressing the surrounding structures. The cyst was fenestrated and a biopsy was taken from the cyst wall. The pathological analysis along with specified histological markers indicated the neuroglial nature of the cyst.

CONCLUSION

The rising of a neuroglial cyst from the nerve sheath is a finding that brings other possible origins of neuroglial cysts into consideration.

Agenesis of the corpus callosum with interhemispheric cyst: clinical implications and outcome

We describe two cases of agenesis of the corpus callosum (ACC) with interhemispheric cyst (IHC). Case 1: a male infant was born at 36 weeks gestation with a history of second trimester fetal ultrasound (US) scan and MRI showing ACC with IHC. His head circumference at birth and 5 months was at 90th centile. He developed infantile spasm and electroencephalogram showed hypsarrhythmia at 5 months of age. Seizures were controlled. He is under evaluation for surgical treatment. Case 2: ACC with a midline cyst was reported in the midtrimester US scan of a male infant. Subsequent fetal scans showed increasing size of the cyst. At birth, he had macrocephaly with a head circumference above 97th centile. MRI of the brain confirmed ACC with IHC. The parents refused a cystoperitoneal shunt offered. The child displayed gross neurodevelopmental delay with progressive hydrocephalus on follow-up and succumbed to aspiration pneumonia at 22 months of age.

Endoscopic treatment of suprasellar cysts without hydrocephalus

OBJECTIVE At present, endoscopic treatment is advised as the first procedure in cases of suprasellar arachnoid cysts (SSCs) with hydrocephalus. However, the appropriate therapy for SSCs without hydrocephalus has not been fully determined yet because such cases are very rare and because it is usually difficult to perform the neuroendoscopic procedure in patients without ventriculomegaly given difficulties with ventricular cannulation and the narrow foramen of Monro. The purpose of this study was to find out the value of navigation-guided neuroendoscopic ventriculocystocisternostomy (VCC) for SSCs without lateral ventriculomegaly. METHODS Five consecutive patients with SSC without hydrocephalus were surgically treated using endoscopic fenestration (VCC) guided by navigation between March 2014 and November 2015. The surgical technique, success rate, and patient outcomes were assessed and compared with those from hydrocephalic patients managed in a similar fashion. RESULTS The small ventricles were successfully cannulated using navigational tracking, and the VCC was accomplished in all patients. There were no operative complications related to the endoscopic procedure. In all patients the SSC decreased in size and symptoms improved postoperatively (mean follow-up 10.4 months). CONCLUSIONS Endoscopic VCC can be performed as an effective, safe, and simple treatment option by using intraoperative image-based neuronavigation in SSC patients without hydrocephalus. The image-guided neuroendoscopic procedure improved the accuracy of the endoscopic approach and minimized brain trauma. The absence of hydrocephalus in patients with SSC may not be a contraindication to endoscopic treatment.

[Arachnoid cysts: Embriology and pathology]

There is still great controversy surrounding the origin of the arachnoid cyst. The most accepted theory in the case of congenital cysts explains how they are formed from an anomalous development of the arachnoid membrane, which is unfolded allowing the accumulation of cerebrospinal fluid inside and creating a cyst. This theory seems to explain the origin of convexity and sylvian cistern arachnoid cysts, whereas those in other locations might be due to other mechanisms. In the anatomopathological analysis, the arachnoid cyst wall can be seen as having few differences from normal, although thickened due to an increase quantity of collagenous material. A description of the embryological development of the arachnoid layer and cyst formation is presented, describing the main anatomopathological findings.

Outcome of 12 antenatally diagnosed fetal arachnoid cysts: case series and review of the literature

OBJECTIVES

To investigate the natural history, associated abnormalities and outcome of 12 fetuses with arachnoid cyst diagnosed antenatally by ultrasound and magnetic resonance imaging and to compare the outcome with cases in the literature.

METHODS

A retrospective study of all cases of antenatally detected fetal arachnoid cysts was performed in patients referred to a tertiary unit between 2007 and 2013. Associated abnormalities, pregnancy outcome and postnatal follow-up were analyzed. All papers about prenatally diagnosed arachnoid cysts, of the last 30 years, were evaluated (search terms in Pubmed: "prenatal diagnosis", "Arachnoid Cysts").

RESULTS

Fetal arachnoid cysts were diagnosed in 12 fetuses, 9 were females. The mean gestational age of diagnosis was 28 1/7 (range 19 1/7-34 2/7 weeks). A total of 9 cases were supratentorial, 3 were located in the posterior fossa. In 10 cases a fetal MRI was performed which confirmed brain compression in 4 out of 5 supratentorial arachnoid cyst. MRI did not reveal other malformations nor signs of nodular heterotopia. Only one fetus presented with additional major anomalies (bilateral ventricumomegaly of >20 mm and rhombencephalosynapsis) leading to a termination of pregnancy. Two neonates underwent endoscopic fenestration of the arachnoid cyst in the first week of life with no additional intervention in childhood. All but one (10/11) had a favorable postnatal outcome. This child suffered from visual impairment at autism was diagnosed at the age of 5. One child had a surgical correction of strabismus later in childhood. In one child the infratentorial arachnoid cyst regressed spontaneously on ultrasound and MRI in the postnatal period.

CONCLUSIONS

The majority of arachnoid cysts in this series are of benign origin and remain stable. Based on the current series and the review of the literature, in the absence of other associated anomalies and when the karyotype is normal, the postnatal overall and neurological outcome is favorable. Large suprasellar arachnoid cysts however, may cause visual impairment and endocrinological disturbances. Rarely associated cerebral or cerebellar malformations are present. Modern postnatal management of suprasellar arachnoid cyst consists of endoscopic cystoventriculostomy.

Anatomical variations and neurosurgical significance of Liliequist's membrane

INTRODUCTION

Liliequist's membrane is an arachnoid membrane that forms a barrier within the basilar cisternal complex. This structure is an important landmark in approaches to the sellar and parasellar regions. The importance of this membrane was largely recognized after the advance of neuroendoscopic techniques. Many studies were, thereafter, published reporting different anatomic findings.

METHOD

A detailed search for studies reporting anatomic and surgical findings of Liliequist's membrane was performed using "PubMed," and included all the available literature. Manual search for manuscripts was also conducted on references of papers reporting reviews.

RESULTS

Liliequist's membrane has received more attention recently. The studies have reported widely variable results, which were systematically organized in this paper to address the controversy.

CONCLUSION

Regardless of its clinical and surgical significance, the anatomy of Liliequist's membrane is still a matter of debate.

A de novo GLI3 mutation in a patient with acrocallosal syndrome

Acrocallosal syndrome is characterized by postaxial polydactyly, macrocephaly, agenesis of the corpus callosum, and severe developmental delay. In a few patients with this disorder, a mutation in the KIF7 gene has been reported, which was associated with impaired GLI3 processing and dysregulaton of GLI3 transcription factors. A single patient with acrocallosal syndrome and a de novo p.Ala934Pro mutation in GLI3 has been reported, whereas diverse and numerous GLI3 mutations have also been described in syndromes with overlapping clinical manifestations, including Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, trigonocephaly with craniosynostosis and polydactyly, oral-facial-digital syndrome, and non-syndromic polydactyly. Here, we describe a second patient with acrocallosal syndrome, who has a de novo, novel c.2786T>C mutation in GLI3, which predicts p.Leu929Pro. This mutation is in the same domain as the mutation in the previously reported patient. These data confirm that mutations in GLI3 are a cause of the acrocallosal phenotype.

Spinal dysraphism

To review the clinical features and current understanding of spina bifida with an emphasis on the Indian Scenario. Selected articles and current English language texts were reviewed. The authors experience was also reviewed and analysed. Spina bifida is a common congenital anomaly encompassing a wide spectrum of neural tube defects.It is broadly classified as spina bifida aperta and occulta. With the prenatal screening, the incidence of aperta is gradually declining, whereas the detection of occulta has increased with the advent of magnetic resonance imaging. Over the years, the understanding of pathophysiology has made a significant changein the management of these anomalies. Early detection and complete correction can significantly reduce the neurological disability. This article is an overview of spina bifida with a special emphasis on Indian scenario.

Suprasellar cysts: clinical presentation, surgical indications, and optimal surgical treatment

Background

To describe the clinical presentation of suprasellar cysts (SSCs) and surgical indications, and compare the treatment methods of endoscopic ventriculocystostomy (VC) and ventriculocystocisternotomy (VCC).

Methods

We retrospectively reviewed the records of 73 consecutive patients with SSC who were treated between June 2002 and September 2009. Twenty-two patients were treated with VC and 51 with VCC. Outcome was assessed by clinical examination and magnetic resonance imaging.

Results

The patients were divided into five groups based on age at presentation: age less than 1 year (n = 6), 1-5 years (n = 36), 6-10 years (n = 15), 11-20 years (n = 11), and 21-53 years (n = 5). The main clinical presentations were macrocrania (100%), motor deficits (50%), and gaze disturbance (33.3%) in the age less than 1 year group; macrocrania (75%), motor deficits (63.9%), and gaze disturbance (27.8%) in the 1-5 years group; macrocrania (46.7%), symptoms of raised intracranial pressure (ICP) (40.0%), endocrine dysfunction (40%), and seizures (33.3%) in the 6-10 years group; symptoms of raised ICP (54.5%), endocrine dysfunction (54.5%), and reduced visual field or acuity (36.4%) in the 11-20 years group; and symptoms of raised ICP (80.0%) and reduced visual field or acuity (40.0%) in the 21-53 years group. The overall success rate of endoscopic fenestration was 90.4%. A Kaplan-Meier curve for long-term efficacy of the two treatment modalities showed better results for VCC than for VC (p = 0.008).

Conclusions

Different age groups with SSCs have different main clinical presentations. VCC appears to be more efficacious than VC.

[The outcome of children presenting with a prenatally diagnosed arachnoid cyst]

AIM

Evaluate the outcome of children with prenatally diagnosed arachnoid cysts.

MATERIAL AND METHODS

Retrospective study of seventeen cases of children who were diagnosed with an arachnoid cyst during prenatal MRI between July 1994 and January 2007 and followed up for a mean 6 years and 6 months. Follow-up was based on evaluation of clinical files and contacts with the physicians who were following the children. The children were divided into three groups: group 1 normal development, group 2: minor clinical signs, normal schooling, group 3: major clinical symptoms, schooling disturbed.

RESULTS

Eight of the 17 patients included in this study underwent derivation surgery for the cyst. Eight of the 17 children were in group 1, and 3 in group 2. Four of the 6 children in group 3 had associated symptoms. Two of the children in group 3 present with a supratentorial cyst, and 4 with a cyst of the posterior fossa.

CONCLUSION

The prenatal diagnosis of a arachnoid cyst should be accompanied by a search for associated lesions. The risk of hydroencephalitis should be explained to the parents.

Fetal central nervous system malformations on MR images

Sonography is the method of choice for prenatal malformation screening but it does not always provide sufficient information for correct diagnosis or adequate abnormality evaluation. Fetal magnetic resonance imaging (MRI) is considered as a valuable second line imaging tool for confirmation, completion and correction of sonographic findings. Fetal MRI has proven its value in the evaluation of central nervous system pathologies, especially of midline and posterior fossa malformations. The role of MRI is not only to confirm or exclude possible lesions but also to define their full extent, aiding in their characterization, and to demonstrate associated abnormalities. The authors describe the most common anomalies of CNS revealed by fetal MRI in a chronological way related to the age of pregnancy, with a review of own MR images and with reference to the literature and own experience.

Endoscopic treatment of suprasellar arachnoid cysts

OBJECTIVE

Arachnoid cysts constitute 1% of all intracranial mass lesions not resulting from trauma. Suprasellar arachnoid cysts (SACs) are uncommon. Obstructive hydrocephalus is the most common cause of initial symptoms and occurs in almost 90% of the patients with suprasellar arachnoid cyst. We report on 17 patients with suprasellar arachnoid cyst who were treated with neuroendoscopic intervention.

MATERIALS AND METHODS

Seventeen patients with SAC had been operated on between 1999 and 2007 in our institution. Five patients had previously undergone shunting procedures or craniotomy. Nine boys and eight girls ranged in age from 4 months to 17 years (mean 53.2 months). All patients had hydrocephalus. A wide ventriculocystostomy (VC) or a ventriculo-cysto-cisternostomy (VCC) was done by using rigid neuroendoscopes. Psychometric evaluation was administered postoperatively, when possible. Follow-up of the patients ranged from 6 months to 7 years (mean 41.6 months).

RESULTS

Of the 17 patients, 12 underwent endoscopic procedure as the primary surgery. VC only was performed in the first patient. In the remaining 16 patients, VCC was done. A slit-valve mechanism was observed in 14 patients. Three patients needed a VP shunt, despite a successful VCC. Three of five patients, younger than 1 year of age became shunt dependent and none of the patients older than 1 year of age needed shunting. In four patients presented with shunt malfunction, the shunts were removed after endoscopic surgery. Only one subject's total score was under the normal IQ limits but her subtests scores were heterogeneous. However, there was marked discrepancy among her subtests scores.

CONCLUSION

Endoscopic surgery should be the first choice in the management of SACs. Neuroendoscopic VCC is successful in the majority of the cases.

Nationwide survey of the etiology and associated conditions of prenatally and postnatally diagnosed congenital hydrocephalus in Japan

A nationwide survey in 2000 investigated the causative and associated central nervous system (CNS) lesions of congenital hydrocephalus in Japan. The etiology and associated diseases in 393 patients with congenital hydrocephalus were analyzed and compared between 193 patients with prenatally diagnosed (fetal) hydrocephalus and 181 with postnatally diagnosed (infantile) hydrocephalus. Of 393 patients of congenital hydrocephalus, 355 (90.3%) had primary hydrocephalus and 28 (7.1%) had secondary hydrocephalus. Of 355 patients with primary hydrocephalus, 85 (23.9%) had simple hydrocephalus associated with no other CNS anomaly and 270 (76.1%) had complicated hydrocephalus associated with other CNS anomalies. Destructive cystic lesions, holoprosencephaly, and agenesis of the corpus callosum were significantly predominant in fetal hydrocephalus. Arachnoid cyst was somewhat predominant in infantile hydrocephalus. The majority of cases of congenital hydrocephalus were primary hydrocephalus and two thirds were complicated hydrocephalus. Several complications showed marked predominance in fetal hydrocephalus.

Prenatal diagnosis of arachnoid cysts

Arachnoid cysts are a rare central nervous system malformation, representing only 1% of all intracranial masses in newborns. Primary (congenital) arachnoid cysts are benign accumulation of clear fluid between the dura and the brain substance throughout the cerebrospinal axis in relation to the arachnoid membrane and do not communicate with the subarachnoid space. Secondary (acquired) arachnoid cysts result from hemorrhage, trauma, and infection and usually communicate with the subarachnoid space. The common locations of arachnoid cysts are the surface of the brain at the level of main brain fissures, such as sylvian, rolandic and interhemispheric fissures, sella turcica, the anterior cranial fossa, and the middle cranial fossa. Arachnoid cysts may be associated with ventriculomegaly and dysgenesis of corpus callosum. Prenatal ultrasound and magnetic resonance imaging have led to the increased diagnosis of fetal arachnoid cysts. This article provides a thorough review of fetal arachnoid cysts, including prenatal diagnosis, differential diagnosis and associated chromosomal abnormalities, as well as comprehensive illustrations of perinatal imaging findings of fetal arachnoid cysts. Prenatal diagnosis of intracranial hypoechoic lesions should include a differential diagnosis of arachnoid cysts and prompt genetic investigations.

Treatment of suprasellar cysts and patient outcome

OBJECT

The authors sought to determine the natural history of and optimal treatment for suprasellar cysts (SSCs).

METHODS

Three hundred forty-two patients harboring intracranial cysts presented to the authors' neurosurgery unit between January 1986 and August 2004. The patients' records were reviewed to assess symptomatology, results of imaging studies, and outcome according to mode of treatment. Thirty-three patients (9.6%) were eligible for this study. Nine SSCs were diagnosed prenatally and 24 were identified postnatally (range 0 months-18.2 years, mean 5.6 years). The mean follow-up period was 66.8 +/- 44.6 months (standard deviation). Seven cysts were left untreated, six (66%) detected before birth and one (4.5%) after birth. Of the 26 patients who required surgery, three were admitted elsewhere for complications of shunt surgery. A ventriculocystostomy (VC) was performed in all three of these patients, but the treatment failed in two. The primary treatment in the remaining 23 children was: open fenestration in two patients, VC in seven, ventriculocystocisternostomy (VCC) in 13, and cystoperitoneal (CP) shunt in one patient. Both open fenestration procedures were successful, as was the CP shunt insertion. The success rate of primary endoscopic surgery, although not statistically significant, was higher for VCCs (11 [85%] of 13 patients) than for VCs (four [57%] of seven patients). None of the patients' preoperative endocrine disorders resolved postoperatively. The distribution of intellectual and developmental quotients paralleled the normal range. Intellectual performance was unrelated to patient-specific factors or to treatment modalities.

CONCLUSIONS

Most SSCs are of moderate size, are stable and asymptomatic, and have a favorable outcome. Treatment is required when the cyst evolves or the patient is symptomatic, but endocrine disturbances alone are not an indication for surgery. When hydrocephalus is present, endoscopic fenestration is the primary treatment of choice. The goal of the procedure should be to open the cyst into both the ventricles and the cisterns. Intellectual capability after treatment at outcome is not related to age at diagnosis, initial or final cyst size, presence or absence of hydrocephalus, or type of endoscopic treatment.

A large arachnoid cyst of the lateral ventricle extending from the supracerebellar cistern--case report

BACKGROUND

The pathogenetic mechanism of intraventricular arachnoid cyst development is still controversial, but is believed to originate from the vascular mesenchyme or as an extension of the arachnoid cyst in the subarachnoid space into the ventricle through the choroidal fissure. We report a case supporting the extension hypothesis and suggest differential points between an intraventricular arachnoid cyst that extended from the supracerebellar space and a lateral ventricular diverticulum that extended into the supracerebellar cistern.

CASE DESCRIPTION

A 12-month-old girl presented with macrocephaly and developmental delay. Her magnetic resonance imaging showed an arachnoid cyst that had developed from the supracerebellar space in the posterior fossa, and which extended into the left lateral ventricle resulting in expansion of the left lateral ventricle and displacing the choroids plexus anteriorly and laterally and the midline to the right. We treated an intraventricular arachnoid cyst by endoscopic fenestration resulting in dramatic reduction of the intraventricular arachnoid cyst with large bilateral subdural fluid collection. We performed a subduroperitoneal shunt for subdural fluid collection and subsequent cystoperitoneal shunt for the remnant cyst.

CONCLUSION

We suggest that this case supports the extension hypothesis from the subarachnoid space through the choroidal fissure into the lateral ventricle. We also suggest that one of the radiological differential points between an intraventricular arachnoid cyst and a ventricular diverticulum is displacement and compression of the choroid plexus of the lateral ventricle.

Imaging of fetal cerebral ventriculomegaly: a guide to management and outcome

Ultrasound imaging is the screening modality of choice for initial evaluation of the fetal central nervous system. However, there are times when fast magnetic resonance imaging (MRI) provides information additional to that available from ultrasound. This review will: (1) discuss the ultrasound evaluation of ventriculomegaly and its associated anomalies; (2) illustrate and expand upon the type of additional information MRI can provide beyond that which is available from ultrasound; and (3) discuss how this additional information can alter diagnosis as well as change maternal counselling and case management.

Association of a fetal quadrigeminal cyst with a possibly congenital thalamic astrocytoma

CASE REPORT

This article reports on the exceptional association of a fetal quadrigeminal malformative cyst with a possibly congenital pilocytic astrocytoma of the pulvinar. Both the cyst and the tumor required treatment due to their postnatal growth.

DISCUSSION

Treatment modalities and difficulties are emphasized, as well as the difficulties of prenatal counseling.

Fetal and neonatal neurologic consultations: identifying brain disorders in the context of fetal-maternal-placental disease

Pediatric neurologists provide an important consultative role for the fetus or neonate with a suspected brain disorder. Although most consultations are initiated after birth, neonatal neurologic dysfunction may be reflective of fetal brain damage or maldevelopment. Maternal or placental/cord disease states can predispose the fetus or neonate to brain disorders during the antepartum, intrapartum, or early postpartum periods. Neurologists must therefore consider maternal, placental, and fetal conditions on which a neonatal encephalopathy may be superimposed, with or without recent brain injury. This review suggests how the pediatric neurologist can contribute more effectively to fetal and neonatal neurologic evaluations regarding etiologies and mechanisms of brain injury; their role will enhance diagnostic services composed of maternal-fetal specialists, placental and pediatric pathologists, neonatologists, neurosurgeons, geneticists, and other pediatric subspecialists. Selected examples of structural markers during fetal life, and functional markers during neonatal life, illustrate the wide spectrum of disease states that are highly dependent on the timing and location of brain injury. The pediatric neurologist has the opportunity to integrate these complementary lines of investigation into a responsive consultative opinion, which is both medically accurate and ethical, responsible to the welfare of the mother and child.