Posterior Fossa Arachnoid Cyst Research Articles

Structural deviations of the posterior fossa and the cerebellum and their cognitive links in a neurodevelopmental deletion syndrome.

High-impact genetic variants associated with neurodevelopmental disorders provide biologically-defined entry points for mechanistic investigation. The 3q29 deletion (3q29Del) is one such variant, conferring a 40-100-fold increased risk for schizophrenia, as well as high risk for autism and intellectual disability. However, the mechanisms leading to neurodevelopmental disability remain largely unknown. Here, we report the first in vivo quantitative neuroimaging study in individuals with 3q29Del (N = 24) and neurotypical controls (N = 1608) using structural MRI. Given prior radiology reports of posterior fossa abnormalities in 3q29Del, we focused our investigation on the cerebellum and its tissue-types and lobules. Additionally, we compared the prevalence of cystic/cyst-like malformations of the posterior fossa between 3q29Del and controls and examined the association between neuroanatomical findings and quantitative traits to probe gene-brain-behavior relationships. 3q29Del participants had smaller cerebellar cortex volumes than controls, before and after correction for intracranial volume (ICV). An anterior-posterior gradient emerged in finer grained lobule-based and voxel-wise analyses. 3q29Del participants also had larger cerebellar white matter volumes than controls following ICV-correction and displayed elevated rates of posterior fossa arachnoid cysts and mega cisterna magna findings independent of cerebellar volume. Cerebellar white matter and subregional gray matter volumes were associated with visual-perception and visual-motor integration skills as well as IQ, while cystic/cyst-like malformations yielded no behavioral link. In summary, we find that abnormal development of cerebellar structures may represent neuroimaging-based biomarkers of cognitive and sensorimotor function in 3q29Del, adding to the growing evidence identifying cerebellar pathology as an intersection point between syndromic and idiopathic forms of neurodevelopmental disabilities.

Widening the clinical, radiological and genetic spectrum of autosomal recessive ataxia of Charlevoix-Saguenay in Indian patients.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), classically presenting as a triad of early-onset cerebellar ataxia, lower extremity spasticity and peripheral neuropathy, is caused by mutations in SACS gene which encodes the protein sacsin. To provide new insight into the occurrence of SACS mutations in South India. Patients with three cardinal features of ARSACS-peripheral neuropathy, cerebellar ataxia, and pyramidal tract signs were included. Nine patients were clinically identified and genetically evaluated. Mutation screening of SACS by targeted sequencing of 40 recessive ataxia genes panel by next-generation sequencing was conducted. Additional investigations included magnetic resonance imaging (MRI), fundoscopy, optical coherence tomography (OCT) and nerve conduction studies (NCS). Functional disability was assessed by the Spinocerebellar Degeneration Functional Score. Two hundred and fifteen cerebellar ataxia patients were screened, and 9 patients with cerebellar ataxia with spasticity, peripheral neuropathy and MRI brain characteristics, consistent with a clinical diagnosis of ARSACS were identified, of which 7 patients were identified to have mutation in the SACS gene and are detailed hereafter. Age of presentation ranged from 20 to 55years (29.8 ± 11.9) with a mean disease duration of 12.7years (SD-7.65, range 5-22years). All except one had onset of symptoms in the form of an ataxic gait noticed before 20years of age. Additional features were subnormal intelligence (4/7), slow and hypometric saccades (1/7), seizures (1/7), kyphoscoliosis (1/7) and dysmorphic facies (1/7). SDFS was 3 in 5/7 patients signifying moderate disability with independent ambulation. MRI showed cerebellar atrophy with predominant atrophy of the superior vermis (7/7), horizontal linear T2 hypointensities in the pons(7/7), hyperintensities where lateral pons merges with the middle cerebellar peduncle (MCP) (7/7) well seen in fluid-attenuated inversion recovery (FLAIR) images, thickening of MCP (3/7), symmetric lateral thalamic hyperintensities (6/7), posterior fossa arachnoid cyst (4/7),thinning of posterior mid-body of corpus callosum (7/7), marginal mineralisation of the basal ganglia (7/7), bilateral parietal atrophy (7/7) and thinning of corticospinal tract on diffusion tensor imaging (DTI) (7/7). We identified pathogenic homozygous frameshift mutations in the SACS gene in six patients (including two siblings), while one patient had a heterozygous pathogenic deletion. This is the largest series of genetically confirmed ARSACS patients from India highlighting the clinical, ophthalmological, imaging and genetic features of this cohort.

Endoscopic Fenestration of Posterior Fossa Arachnoid Cysts

Introduction: Posterior Fossa arachnoid cysts (PFAC) are rare lesions in the childhood. Owing to the wide variety of cystic malformations within the posterior cranial fossa, PFAC have long attracted the attention of pediatric neurosurgeons because they can produce not only neurological symptons but also behaviro and learning deficts, in addition to presenting major surgical challenges. Surgical treatment is warranted in symptomatic patients. Nowadays, neuroendoscopic techniques have established themselves as the treatment of choice of these lesions.
 Patients and Methods: We present four cases of symptomatic PFAC which were treated using endoscopic neurosurgery. Endoscopic approaches were defined by the presence of hydrocephalus, and discussed in each case.
 Results : Two cases of quadrigeminal plate cysts, predominantly occupying the infratentorial compartment , one case of supracerebellar cyst and one case of cerebellopontine angle were treated with good results. However, one case of quadrigeminal plate cyst developed a communicating hydrocephalus, requiring placement of cyst-ventricle peritoneal shunt, guided by the neuroendoscope.
 Discussion and Conclusion : A literature review was performed. The clinical features, the advantages and disadvantages of several surgical treatments are discussed. Symptomatic PFAC should be treated. The relatively good results using endoscopic fenestration buttresses our use as a first-line surgery.

Posterior Fossa Arachnoid Cysts as Findings in an Ataxia Clinic

The first description of arachnoid cysts was made by the English physician Richard Bright in 1827, under the name “serous cysts”. He described two cases, both discovered by autopsy, in his book “Reports of Medical Cases.

Posterior Fossa Sub-Arachnoid Cysts Observed in Patients with Bipolar Disorder: a Retrospective Cohort Study.

Posterior fossa arachnoid cysts (PFACs) are rare congenital abnormalities observed in 0.3 to 1.7% of the population and are traditionally thought to be benign. While conducting a neuroimaging study investigating cerebellar structure in bipolar disorder, we observed a higher incidence of PFACs in bipolar patients (5 of 75; 6.6%) compared to the neuronormative control group (1 of 54; 1.8%). In this report, we detail the cases of the five patients with bipolar disorder who presented with PFACs. Additionally, we compare neuropsychiatric measures and cerebellar volumes of these patients to neuronormative controls and bipolar controls (those with bipolar disorder without neuroanatomical abnormalities). Our findings suggest that patients with bipolar disorder who also present with PFACs may have a milder symptom constellation relative to patients with bipolar disorder and no neuroanatomical abnormalities. Furthermore, our observations align with prior literature suggesting an association between PFACs and psychiatric symptoms that warrants further study. While acknowledging sample size limitations, our primary aim in the present work is to highlight a connection between PFACs and BD-associated symptoms and encourage further study of cerebellar abnormalities in psychiatry.

Surgical treatment and outcome of posterior fossa arachnoid cysts in infants.

The aim of this cohort study was to describe and analyze the surgical treatment and outcome of posterior fossa arachnoid cysts (PFACs) in infants. Patients presenting with a PFAC at infancy or prenatally, between the years 2000 and 2019, and who were surgically treated before the age of 2 years, were included in this study. Patient data were retrospectively collected including baseline characteristics and surgical variables. Factors related to revision surgery were analyzed through uni- and multivariate analysis. Thirty-five patients, of whom 54.3% were male, were included. The cyst was diagnosed prenatally in 23 patients (65.7%). Surgery was typically recommended after a mean cyst follow-up of 3.4 ± 3.9 months, with a mean age at surgery of 6.1 ± 5.1 months. In 54.3% of patients (n = 19), surgery was performed before the age of 6 months. The PFAC was treated purely neuroendoscopically in 57.1% of patients (n = 20), while 28.6% of patients underwent open cyst procedures (n = 10), 5.7% (n = 2) were treated with a shunt, and 8.6% (n = 3) underwent a combined procedure. Additional surgery was required in 31.4% of patients (n = 11; mean 2.36 ± 2.11 surgeries per patient). At the last follow-up (61.40 ± 55.33 months), no mortality or permanent morbidity was seen; radiological improvement was apparent in 83.9% of the patients. Those patients treated before the age of 6 months (p = 0.09) and who presented before surgery with a stable cyst size that was maintained throughout preoperative monitoring (p = 0.08) showed a trend toward higher revision rates after surgical treatment. PFACs in infancy may require surgical treatment before the age of 6 months. Navigated endoscopy was a valid surgical option. Overall mortality or permanent morbidity was rare. Additional surgery was required in up to 30% of the patients; younger age and a preoperatively stable cyst might be risk factors for revision surgery.

Endoscopic management of periventricular and intraventricular arachnoid cysts

IntroductionThe most successful surgical management of periventricular and intraventricular cysts is still a matter of debate. Up to the early 1990s, open cyst fenestration and cystoperitoneal shunts were the only options available. Recently, different endoscopic approaches to these lesions have gained popularity.MethodsEighteen endoscopic procedures were performed for the treatment of arachnoid cysts in 18 patients. Sylvian fissure arachnoid cysts were excluded from this study. Ten of them were females and eight were males with their ages ranging from 6 months to 50 years with a mean of 16 years. All patients were prospectively observed.ResultsSeven of the arachnoid cysts were in the suprasellar region, 5 in the quadrigeminal region, 2 in the posterior fossa, 2 parietal, and 2 intraventricular. Seventeen cases (94%) had hydrocephalus. The main presenting manifestations were those of increased intracranial pressure. All fenestrations were done in the lateral ventricle except for the 2 cases with posterior fossa arachnoid cysts, the fenestrations were done to the fourth ventricle. Endoscopic ventriculocytostomies (VC) were performed in 14 cases without operative complications and no stents were placed. Endoscopic cystocisternostomies (C) were done in all suprasellar cases. Endoscopic cystoventriculostomies (CV) were done in 4 cases. The mean surgical time was 1 h. The mean follow-up period was 15 months. Symptoms improved in 17 cases. Seventeen cases demonstrated a significant decrease of the cysts’ size in the postoperative computed tomography (CT) and magnetic resonance imaging (MRI). A single case developed a complication in the form of subdural hygroma which required no intervention and was managed conservatively.ConclusionEndoscopic management of periventricular and intraventricular arachnoid cysts is a useful safe option in the management of arachnoid cysts related to the ventricular system.

Microsurgical treatment of a large posterior fossa arachnoid cyst

Introduction: Arachnoid cysts are fluid-filled malformations of the arachnoid tissue. A prevalence in children of 2,6% has been reported[2,3]. Surgical strategies of treatment include open surgery with cyst wall excision , endoscopic fenestration or cystoperitoneal shunting[1,4]. Methods: In this video case, we described the case of a 1 year and 7 months old child who presented with motor development delay, unable to walk, who underwent microsurgical resection of a large posterior fossa arachnoid cyst and communication with the fourth ventricle. Conclusion: Microsurgery approach provides a safe anatomic control over the cyst and the recognition of floor of the fourth ventricle.

Dandy-Walker Malformation

Dandy-Walker Malformation

Symptomatic hemiparkinsonism due to extensive middle and posterior fossa arachnoid cyst: case report

IntroductionIntracranial neoplasms are an uncommon cause of symptomatic parkinsonism. We here report a patient with an extensive middle and posterior fossa arachnoid cyst presenting with parkinsonism that was treated by neurosurgical intervention.MethodsRetrospective chart review and clinical examination of the patient.Case reportThis 55-year-old male patient with hemiparkinsonism and recurrent bouts of headaches was first diagnosed in 1988. CT scans revealed multiple cystic lesions compressing brainstem and basal ganglia, which were partially resected. Subsequently, the patient was free of complaints for 20 years. In 2009 the patient presented once more with severe unilateral tremor and thalamic pain affecting the right arm. Despite symptomatic treatment with L-Dopa and pramipexole symptoms worsened over time. In 2014 there was further progression with increasing hemiparkinsonism, hemidystonia, unilateral thalamic pain and pyramidal signs. Repeat CT scanning revealed a progression of the cysts as well as secondary hydrocephalus. Following repeat decompression of the brainstem and fenestration of all cystic membranes parkinsonism improved with a MDS- UPDRS III score reduction from 39 to 21. Histology revealed arachnoid cystic material.ConclusionWe report on a rare case of recurrent symptomatic hemiparkinsonism resulting from arachnoid cysts.

Blakeʼs Pouch Cysts and Differential Diagnoses in Prenatal and Postnatal MRI

The clinical variability of Blake's pouch cysts (BPC) may range from asymptomatic via ataxia to sequelae of decompensated hydrocephalus. On the other hand, Dandy-Walker malformation (DWM) and cerebellar vermis hypoplasia generally correlate with less favorable neurologic development. The aim was to illustrate the potential of prenatal and postnatal neuroimaging to distinguish aBPC or persistent BP from other posterior fossa malformations. This pictorial review addresses the inconsistent nomenclature, clinical features, and magnetic resonance imaging (MRI) patterns of BPC and five differential diagnoses. The MRI findings of 11 patients, acquired at up to 3 T in 3 institutions, are demonstrated. Furthermore, the literature was searched for recent improvements in genetic and embryological background knowledge. Posterior fossa malformations often resemble each other and may even be imitated by sequelae of hemorrhagic, ischemic or infectious disruptions, i.e. congenital anomalies of morphology despite normal developmental potential. Hydrocephalus is atypical, albeit not always congenital finding in BPC. It is frequently associated with cerebellar disruptions and DWM; however, it is also arare complication of posterior fossa arachnoid cysts. Amoderately elevated vermis needs follow-up to confirm persistent BP versus vermian hypoplasia or DWM. The fetal cerebellar tail, previously assumed to be specific for DWM, may be imitated in cases of persistent BP. The accurate diagnosis of isolated BPC is not always straightforward, which is especially critical in the context of fetomaternal medicine. Adetailed description of posterior fossa malformations is to be preferred over unspecific terminology.

Posterior Fossa Arachnoid Cyst in a Pediatric Population is Associated with Social Perception and Rest Cerebral Blood Flow Abnormalities.

Posterior fossa arachnoid cysts (PFAC) may produce not only neurological symptoms but also other symptoms still poorly understood such as behavioral and learning deficits, awkwardness, and difficulties in social interaction. These subtle social impairments have not been formally described and their underlying brain mechanisms remain unknown. In the present case-control study, we aimed to empirically characterize social impairments in a pediatric population with PFAC using eye tracking. In addition, we investigated putative functional cortical abnormalities in these children using arterial spin labeling magnetic resonance imaging. Overall, 15 patients with PFAC (3f, age = 9.4 ± 4 years) and 43 typically developing volunteer children (16f, age = 9.3 ± 3.6 years) were enrolled in this study. Eye tracking was used to record gaze patterns during visualization of social interaction scenes. Viewing times to faces of characters and non-social background were analyzed. A voxel-wise whole-brain analysis was performed to investigate rest cerebral blood flow (CBF) abnormalities. Significantly reduced viewing time to faces was observed in patients compared with controls (p < 0.01). A ROC curve analysis revealed that 30% of PFAC patients presented viewing time to the face lower than the cutoff, while none of the controls did. The whole-brain analysis revealed a significant decrease in rest CBF in PFAC patients compared with controls bilaterally in the superior temporal gyrus and the temporoparietal junction (TPJ) (p < 0.05 FWE). These results suggest that early life PFAC may have an impact on functional activity of the temporal lobe, which could be associated with social perception deficits.

Lesión como malformación de Chiari secundaria a quiste aracnoidal de la cisterna cuadrigémina

Se presenta el caso de una mujer de 31 años de edad con cefalea y cervicalgia que se agravaba con la maniobra de Valsalva, presentando además mareos, encontrándose una malformación de Chiari secundario a un quiste aracnoideo cuadrigeminal. Después de efectuada la resonancia magnética diagnóstica, la paciente fue sometida a descompresión del agujero magno y extirpación del quiste cuadrigeminal, seguido por la resolución tanto de la malformación de Chiari y el quiste. Los síntomas desaparecieron después de la cirugía y han permanecido completamente resuelto hasta la actualidad. En pacientes adultos que presentan signos y síntomas de una malformación de Chiari debido a la compresión de la médula por las las amígdalas cerebelosas, la presencia de un quiste aracnoideo de cisterna cuadrigéminal es una rara patología asociada que puede ser tratada quirúrgicamente.

Do we need to scan the whole neuraxis for coexistent abnormalities in children with surgically treated occult spinal dysraphism?

Spina bifida occulta (SBO) is generally known as a benign isolated entity; however, there are ambiguous approaches for neuroaxial screening in cases of symptomatic SBO among institutions. This study aims to demonstrate the infrequency of cranial anomalies associated with symptomatic SBO and inquire the necessity of cranial radiological surveillance in those patients. Between 2012 and 2016 pediatric patients who were surgically treated in our clinic due to symptomatic SBO were retrospectively evaluated. All radiological findings in craniospinal evaluation were documented. There were 76 patients with mean age of 5.3 years (range 2 months to 17 years), and female predominance (53 female and 23 male patients). Of those, 64 patients had whole neuroaxis investigation including cranial imaging. Among 64 patients with cranial screening, only two patients had occipital encephalocele and posterior fossa arachnoid cyst. There was neither hydrocephalus nor Chiari malformation in our case series. We detected high number of additional spinal abnormalities accompanying to symptomatic SBOs, whereas cranial findings rarely coexisted with them. Therefore, we strongly suggest the radiological screening of whole spinal axis in occult spinal dysraphism with significant spinal findings. On the other hand, cranial imaging as a part of neuraxis screening in cases of symptomatic SBOs is not required in all cases; however, it can be done in selected patients where clinically indicated.

PHACES syndrome – A rare case report

PHACES syndrome stands for posterior fossa malformations–hemangioma–arterial anomalies–cardiac defects–eye abnormalities–sternal cleft all together known as “PHACES syndrome.” It is a rare cutaneous condition characterized by multiple congenital abnormalities. It affects girls nine times more often than boys. A 3-year-old girl presented with hemangioma of the face, palate, lips, and eyelids and developmental delay associated with seizure episodes. In the ocular examination, congenital cataract, choroidal coloboma, and optic disc hypoplasia were seen. Systemically, there were sternal cleft, ventricular septal defect, and posterior fossa arachnoid cyst and central nervous system vascular abnormalities. Diagnosis was made from systemic examination and ocular examination along with imaging study of the head and chest. PHACES syndrome needs to be managed by a multidisciplinary team of experts such as cardiologist, ophthalmologist, neurologist, and neurosurgeon. Every child with PHACES syndrome should be evaluated for glaucoma and associated pituitary function at each visit.

Adult Posterior Cranial Fossa Arachnoid Cyst: A Case Report

Adult posterior fossa arachnoid cysts are rare lesions that are considered to be mostly congenital in origin. We present 49-year-old man admitted with a chief complaint of tremor and balance problems for the past 2 months. He had ataxia on examination. Magnetic resonance imaging revealed a well circumscribed midline cystic lesion of the posterior fossa sharing the same signal characteristics as cerebrospinal fluid and non-communicating to the fourth ventricle. He underwent surgical treatment for his symptomatic posterior fossa arachnoid cyst with a good outcome at 2 years follow up.

Clinical, ophthalmological, imaging and genetic features in Brazilian patients with ARSACS

BackgroundAutosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an important form of inherited ataxia with a varied clinical spectrum. Detailed studies of phenotype and genotype are necessary to improve diagnosis and elucidate this disorder pathogenesis. OBJECTIVE AND METHODS: To investigate the clinical phenotype, retinal architecture, neuroimaging features and genetic profile of Brazilian patients with ARSACS, we performed neurological and ophthalmological evaluation in thirteen Brazilian patients with molecularly confirmed ARSACS, and examined their mutation profiles. Optical coherence tomography protocol (OCT) consisted in peripapillary retinal nerve fiber layer (RNFL) measurement and qualitative analysis of perifoveal scans. Neuroimaging protocol accessed the frequency of atrophy in cerebellum, corpus callosum and parietal lobe, brainstem signal abnormalities, and posterior fossa arachnoid cysts. We reviewed the literature to delineate the ARSACS phenotype in the largest series worldwide. RESULTS: All patients had ataxia and spasticity, and 11/13 had peripheral neuropathy. Macular microcysts were present in two patients. Peripapillary striations, dentate appearance of inner retina and papillomacular fold were found in eleven cases. All individuals exhibited thickening of RNFL in OCT. The most frequent radiological signs were cerebellar atrophy (13/13), biparietal atrophy (12/13), and linear pontine hypointensities (13/13). Genetic analysis revealed 14 different SACS variants, of which two are novel. CONCLUSION: Macular microcysts, inner retina dentate appearance and papillomacular fold are novel retinal imaging signs of ARSACS. Ophthalmological and neuroimaging changes are common findings in Brazilian patients. The core clinical features of ARSACS are ataxia, spasticity and peripheral neuropathy with onset predominantly in the first decade of life.

Posterior fossa arachnoid cyst causing torticollis and gastro-oesophageal reflux in an infant

IntroductionArachnoid cysts (ACs) account for a small proportion of all intracranial lesions. They are often incidental but can become symptomatic and even cause a threat to life. Symptoms are usually due to direct compression of neural elements and/or raised intracranial pressure.Case reportWe report the case of an infant with an enlarging posterior fossa arachnoid cyst (PFAC) causing torticollis and gastro-oesophageal reflux (GOR), the combination of which had been previously unreported in this context. Endoscopic fenestration and cyst decompression were followed by complete resolution of the symptoms. We discuss the possible mechanisms of torticollis and GOR in this context.

Posterior Fossa Arachnoid Cyst Presenting as Negative Symptoms of Psychosis.

Posterior Fossa Arachnoid Cyst Presenting as Negative Symptoms of Psychosis.

Erratum to: Neuropsychological improvement after posterior fossa arachnoid cyst drainage.

Erratum to: Neuropsychological improvement after posterior fossa arachnoid cyst drainage.