Hydrocephalus in Dandy-Walker malformation

Neuroradiological Correlation of the Lateral Third Periventricular, Pituitary Gland and Stalk, Pineal Gland, Cerebral Aqueduct, and Foramen Magendie and Luschka With Intraventricular Neuroendoscopic Images: A Case Series

Neuroendoscopy procedures in pediatrics have expanded beyond the endoscopic third ventriculostomy. As such, a direct and angled endoscope allows further visualization around the corner, capturing the surrounding anatomy. Intraoperative live images look different than radiological images. Hence, in this single institutional experience, we correlate neuroradiology images with intraoperative intraventricular endoscopic views of the third-fourth ventricle, pituitary, pineal gland, cerebral aqueduct, and foramen magendie and luschka. Our collective case series reveals a few interesting case scenarios of normal and abnormal findings during the procedure. Careful navigation of the neuroendoscope is crucial to prevent injury to the neurovascular bundle. A close relationship with normal anatomy from radiological imaging is necessary to prevent it from getting lost once inside the ventricular cavity.

A large growing occipital meningocele with Dandy-Walker syndrome: A case report and review of the literature

Background

Dandy-Walker syndrome (DWS) is a well-known developmental anomaly. An occipital meningocele (OMC) is recognized as a malformation that is relatively often associated with DWS, but the association of DWS with OMC has been reported in approximately 40 cases. We present herein a rare clinical course of DWS with OMC, in which the sac was small at birth and became progressively larger.

Case Description

A 5-day-old baby boy was referred to our hospital due to OMC. He was born at 33 gestational weeks due to premature rupture of the membranes. He was diagnosed as having DWS associated with OMC. The OMC was covered with skin and its maximum diameter at birth was 3 cm. Magnetic resonance imaging showed an occipital bone defect and continuity of the fourth ventricle, posterior fossa cyst, and OMC sac. The aqueduct was patent, and no hydrocephalus was found. The OMC sac increased progressively with moderate hydrocephalus and reached 7 cm at the age of 54 days when his weight was 2508 g. A cystoperitoneal shunt and repair were performed after sinus venography by contrast computed tomography (CT). At the age of 1 year and 8 months, he had moderate developmental disabilities.

Conclusion

In most cases reported, the OMC was relatively small, and large and giant sizes were reported in only six cases. Almost all cases remained the same size as at birth and underwent surgical intervention as early as possible. It was possible to understand the relationship between the occipital bone defect and abnormal running of sinuses such as the superior sagittal sinus, torcular Herophili, and transverse sinus preoperatively from the CT venography (CTV) image. CTV may be an effective and important method for safely performing repair and shunt.

Dandy-Walker Phenotype with Brainstem Involvement: 2 Distinct Subgroups with Different Prognosis

BACKGROUND AND PURPOSE

Although cardinal imaging features for the diagnostic criteria of the Dandy-Walker phenotype have been recently defined, there is a large range of unreported malformations among these patients. The brainstem, in particular, deserves careful attention because malformations in this region have potentially important implications for clinical outcomes. In this article, we offer detailed information on the association of brainstem dysgenesis in a large, multicentric cohort of patients with the Dandy-Walker phenotype, defining different subtypes of involvement and their potential clinical impact.

MATERIALS AND METHODS

In this established multicenter cohort of 329 patients with the Dandy-Walker phenotype, we include and retrospectively review the MR imaging studies and clinical records of 73 subjects with additional brainstem malformations. Detailed evaluation of the different patterns of brainstem involvement and their potential clinical implications, along with comparisons between posterior fossa measurements for the diagnosis of the Dandy-Walker phenotype, was performed among the different subgroups of patients with brainstem involvement.

RESULTS

There were 2 major forms of brainstem involvement in patients with Dandy-Walker phenotype including the following: 1) the mild form with anteroposterior disproportions of the brainstem structures "only" (57/73; 78%), most frequently with pontine hypoplasia (44/57; 77%), and 2) the severe form with patients with tegmental dysplasia with folding, bumps, and/or clefts (16/73; 22%). Patients with severe forms of brainstem malformation had significantly increased rates of massive ventriculomegaly, additional malformations involving the corpus callosum and gray matter, and interhemispheric cysts. Clinically, patients with the severe form had significantly increased rates of bulbar dysfunction, seizures, and mortality.

CONCLUSIONS

Additional brainstem malformations in patients with the Dandy-Walker phenotype can be divided into 2 major subgroups: mild and severe. The severe form, though less prevalent, has characteristic imaging features, including tegmental folding, bumps, and clefts, and is directly associated with a more severe clinical presentation and increased mortality.

The Management of Hydrocephalus in Midline Posterior Fossa Cystic Collections: Surgical Outcome From a Retrospective Single-Center Case Series of 54 Consecutive Pediatric Patients

BACKGROUND

Hydrocephalus frequently occurs with midline posterior fossa cystic collections. The classification of this heterogeneous group of developmental anomalies, including Dandy-Walker malformation, persisting Blake's pouch, retrocerebellar arachnoid cysts, and mega cisterna magna, is subject of debate. The absence of diagnostic criteria is confusing regarding the ideal management of PFCC-related hydrocephalus.

OBJECTIVE

To decipher the surgical strategy for the treatment of children with PFCC-related hydrocephalus through a retrospective analysis of the surgical outcome driven by their clinical and radiological presentation.

METHODS

This study enrolled patients operated of symptomatic PFCC-related hydrocephalus. Clinical and MRI features were examined, as well as the surgical outcome. Unbiased subgroup classification of the patients was performed with multiple component analysis as a function of imaging characteristics and hierarchical clustering on principal component. Outcome was assessed with binomial logistic regression and Kaplan-Meier analysis.

RESULTS

Fifty-four patients were included between 2007 and 2021. Multiple component analysis suggested that cerebellar and vermian hypoplasia, vermian rotation, basal-tentorial angle, and fastigial angle were strongly correlated. Hierarchical clustering and the distribution of the patients in the bidimensional plot showed the clear segregation of 3 major clusters, which correlated with the radiological diagnosis ( P < .01). Binomial logistic regression and survival analysis showed that endoscopic third ventriculostomy was an effective treatment for patients with persisting Blake's pouch, while failing to control hydrocephalus in most of patients with Dandy-Walker malformation.

CONCLUSION

Preoperative MRI in patients with PFCC-related hydrocephalus is essential to better define the diagnosis. The choice of treatment strategy notably relies on correct radiological diagnosis.

Imaging of congenital and developmental cystic lesions of the brain: a narrative review

INTRODUCTION

Congenital and developmental intracranial cysts represent a large heterogenous group with varied presentations and etiologies. They can range from normal variants to pathologic lesions often associated with known congenital syndromes or acquired insults. While some are incidentally found, others are symptomatic or may become symptomatic over time. The preferred type of neuroimaging for timely diagnosis helps determine appropriate management and treatment, if indicated.

AREAS COVERED

In this narrative review article, authors present a comprehensive description of developmental cystic lesions. Imaging descriptions are provided for each type of cystic lesion as well as several representative images.

EXPERT OPINION

As advanced neuroimaging techniques become more ubiquitous in clinical use, more light may be shed on the natural history of certain intracranial cystic lesions throughout the lifespan. This includes prenatal imaging for early identification and prognostication to surveillance imaging into advanced age to ascertain associations of certain cystic lesions with age-related cognitive dysfunction.

Headache, Loss of Smell, and Visual Disturbances: Symptoms of SARS-CoV-2 Infection? A Case Report

OBJECTIVE

The purpose of this case report is to describe the main components of the history and physical examination that led to idiopathic intracranial hypertension differential diagnosis, which initially was investigated as COVID-19.

METHODS (CASE DESCRIPTION)

A 28-year-old woman complaining of constant headache and loss of smell and taste was suspected as SARS-CoV-2 infection by her general practitioner. She underwent 3 molecular swab tests, all negative, then decided to seek her physical therapist for relieving headache.

RESULTS

The full cranial nerve examination revealed impaired olfactory (CNI), abducens (CN VI), and facial (CN VII) nerves, leading the physical therapist to refer the patient to a neurosurgeon for a suspected central nervous system involvement. The neurosurgeon prescribed a detailed MRI and an ophthalmologic examination, which allowed for the final diagnosis of idiopathic intracranial hypertension.

CONCLUSION

An urgent lumbo-peritoneal shunting surgery resolved the patient's symptoms and saved her sight. Despite the ongoing COVID-19 pandemic, health care professionals must pay attention to properly investigating patients' signs and symptoms using comprehensive clinical reasoning, considering the screening for referral to specialist medical attention.

IMPACT

A thorough physical examination is required for every patient even if patients' signs and symptoms are in line with apparent common and widespread pathologies. Cranial nerve evaluation is an essential component of the physical therapist assessment and decision-making process. The ongoing pandemic highlighted the fundamental assistance of physical therapists toward physicians in the screening and management of musculoskeletal diseases.

Dandy Walker-like malformation in an adult cat with seizures: clinical description and MRI characteristics

Case summary

A 2-year-old male neutered domestic shorthair cat was referred for investigation of a 10-month history of self-limiting, generalised tonic-clonic seizures. The cat was reported to be normal interictally but had always had a static abnormal gait. General physical examination was unremarkable. Neuroanatomical localisation was compatible with a diffuse cerebellar and diffuse forebrain lesion. Complete blood count, biochemistry, bile acid stimulation test, urinalysis, cisternal cerebrospinal fluid (CSF) analysis, Toxoplasma gondii serology and T gondii polymerase chain reaction in CSF were all unremarkable. MRI revealed an abnormal caudal fossa, absent cerebellar vermis and small cerebellar hemisphere with distension of the fourth ventricle. There were no forebrain abnormalities identified in the MRI or CSF changes that could justify the seizures. Considering the clinical presentation, the cat's neurological examination and MRI features, a presumptive diagnosis of Dandy Walker-like malformation (DWLM) and epilepsy of unknown aetiology was made.

Relevance and novel information

This is the first case report of an adult cat diagnosed with cerebellar malformation resembling DWLM and concomitant seizures, its MRI characteristics and long-term follow-up. The 3-year follow-up consultation revealed static neurological status with 2-4 seizures per year. The cat's quality of life remained good at the time of writing.

Endoscopic ultrasonic aspiration of posterior fossa abscess in Dandy-Walker malformation: case report

BACKGROUND

Dandy-Walker malformation (DWM) is a posterior fossa malformation characterized by a huge posterior fossa cyst in communication with the fourth ventricle. Hydrocephalus is associated with more than 80% of cases and is usually treated by shunting. Despite infection being a common complication of the shunt, abscess formation within the cyst was reported only once.

CASE REPORT

A neonate affected by DWM developed a posterior fossa abscess following a shunt infection. The purulent collection was refractory to standard treatment (antibiotics and burr hole drainage); therefore, an endoscopic approach was performed in order to remove the purulent collection under direct vision. This material was aspirated with the help of an endoscopic ultrasonic aspirator. The outcome was favorable, with a resolution of infection and re-implantation of the ventriculo-peritoneal shunt. Surprisingly, post-operative radiological examination showed substantial modification of the anatomy of the posterior fossa with disappearing of the Dandy-Walker cyst. To the best of our knowledge, this is the first documented report of a true Dandy-Walker malformation that modified its anatomical appearance over time.

DISCUSSION AND CONCLUSION

Endoscopic aspiration of intracranial purulent collection should be considered a valid option to manage complicated cases. An endoscopic ultrasonic aspirator may make the procedure more effective and faster.

Children hydrocephalus in Togo: etiologies, treatment, and outcomes

Background

Hydrocephalus is frequent in sub-Saharan African countries. The postinfectious hydrocephalus tends to decrease. The objective of this study was to identify the etiologies and outcomes of hydrocephalus.

Methods

This was a retrospective study of hydrocephalus cases (0-15 years old) treated in the neurosurgery unit of the Sylvanus Olympio Hospital in Lomé over 10 years (2012-2021). At 1 year, the evolution distinguished in two categories: (1) Good psychomotor development: no delay in the acquisition of walking, language, and school. (2) Psychomotor delay: delay in the acquisition of walking, language, and school.

Results

We reported 305 children treated for hydrocephalus representing 1.8% of all neurosurgery unit patients and 34.2% of pediatric pathologies. There was a male predominance (60.6%). We noted second degree consanguinity in 8.5%. The positive maternal serologies were HIV (12.4%), syphilis (8.2%), and toxoplasmosis (2.6%). A malaria episode had been treated during the first trimester in 36.7% of the mothers. The main clinical sign of hydrocephalus was 91.5% of Macrocephalus. Congenital Malformafions were the most common etiologies of hydrocephalus (68.5%). Ventriculoperitoneal shunt was the main surgical method used and 16 deaths were recorded. The medium-term evolution (1 year) was evaluated in 36.1% and noted 61.8% of psychomotor retardation.

Conclusion

This study confirms the trend of the predominance of congenital causes of hydrocephalus in Africa, even if maternal infections can be involved in the development of some of them. The morbimortality of this pathology remains important, especially concerning neurocognitive outcomes.

Refractory psychiatric symptoms and seizure associated with Dandy-Walker syndrome: A case report and literature review

BACKGROUNDS

Dandy-Walker syndrome (DWS) is a group of brain malformations which occasionally accompanied by psychotic symptoms. The co-occurrence of DWS and epilepsy in children is quite rare.

CASE DESCRIPTION

We reported a 14-year-old male who presented with a 8-month history of inconsistent upper limb tremor and accidental seizure. The MRI showed the typical alterations of DWS: cystic dilatation of the fourth ventricle, vermian hypoplasia, enlarged posterior fossa. He received the ventriculoperitoneal shunting (VPS) placement for hydrocephalus and had a symptom-free period for 8 days. Then he experienced a recurrence of involuntary upper limb tremor and behavior disturbance after decreasing the pressure of cerebrospinal fluid (CSF) from 150 to 130 mm Hg. After being treated with Olanzapine 10 mg/d, Clonazepam 3 mg/qn and Valproate acid (VPA) 500 mg/bid for nearly a month, his mental status and psychotic symptoms fluctuated. A search of Pub Med showed little report of hydrocephalus and DWS comorbidity with seizure and psychosis. Here we presented the whole process of a rare disease from the very beginning with all his symptoms, examinations and treatments.

CONCLUSION

VPS placement surgery at an earlier stage may be an effective way to avoid inevitable brain damage so as to improve the clinical outcomes for patients with DWS. Continued treatment with regard to DWS condition may include shunt placement, but it mainly focus on developmental concerns, with occupational and physical therapy along with ongoing supportive psychotherapy to improve the coping skills and quality of life.

Costs of pediatric hydrocephalus treatment for the Brazilian public health system in the Northeast of Brazil

PURPOSE

To estimate the costs of the surgical treatment of pediatric hydrocephalus, specifically ventriculoperitoneal shunt (VPS) and endoscopic third ventriculostomy (ETV), for the Brazilian public health system (SUS).

METHODS

Retrospective cohort study of health records of patients < 14 years of age with a diagnosis of hydrocephalus who underwent VPS or ETV between September 2009 and June 2016, regularly followed up for 24 months.

RESULTS

Seventy-six medical records were included. The groups of children who underwent VPS and ETV consisted of 60 and 16 patients, respectively. Complications during 2 years of follow-up were identified in 56% of the children undergoing VPS and in 18% of those undergoing ETV (p = 0.0103). The initial cost of VPS was lower than that of ETV up to approximately 1 year of post-surgical follow-up. After that, VPS generated higher expenses for the SUS due to higher rates of late post-surgical complications and repeated readmissions.

CONCLUSION

Higher public expenditures were observed in the group of children undergoing VPS due to higher rates of infectious and mechanical complications requiring repeated hospitalizations and prosthesis replacements. Public policies must be tailored to offer the best treatment to children with hydrocephalus and to make judicious use of public resources without compromising the quality of treatment.

Is there a role in the central nervous system development for using corticosteroids to treat meningomyelocele and hydrocephalus?

INTRODUCTION

Myelomeningocele (MMC) is the most frequent neural tube defect and is frequently associated (around 80% of cases) with hydrocephalus (HC). Both diseases can have severe clinical consequences, insomuch as they require surgical treatment whose complications are not negligible, either when performed in utero or after birth. Therefore, clinical therapies that could have an impact on the incidence and progression of MMC and HC would be certainly valuable; however, this is not the current picture, and there are no effective pharmacological treatments for such patients to this day.

AIM AND METHODS

Therefore, knowing that an inflammatory process comes associated with these disorders, mostly due to nervous tissue distension, the present article aimed at reviewing the role of corticosteroids in reducing inflammation and thus improving the outcome of patients with HC and MMC, considering the well-established anti-inflammatory effects of CS.

RESULTS

The systematic review performed herein has found varying results regarding the role of steroids (even though a positive trend was observed) on the treatment and prevention of hydrocephalus, whereas for MMC.

CONCLUSION

There are many reports demonstrating beneficial effects of CS therapy, from a clinical and histopathological point of view.

Occipital encephalocele associated with Dandy-Walker malformation: a case-based review

INTRODUCTION

Occipital encephalocele is a brain malformation that has been remotely associated with Dandy-Walker; only case reports and very small series have been published so far; therefore, their behavior and management are still under investigation. The goal of the present case-based review is to provide a summary of the state of the art in this association.

METHODS AND RESULTS

The pertinent literature has been reviewed, and an exemplary case has been reported (an 11-month-old female with Dandy-Walker malformation and occipital encephalocele). So far, 33 cases have been described, with a mean age at surgery of 5, 1 day). The majority of the cases tend to present with hydrocephalus. There are no specific surgery approaches or global consensus about this association. The management possibly relies on surgery with shunt or encephalocele excision but without a dedicated protocol yet.

CONCLUSIONS

The clinical research on occipital encephalocele in association with Dandy-Walker malformation is just at the beginning. New targets and wide-ranging clinical trials are needed to get an optimal management protocol.

Congenital Malformations of Cerebellum

Advances in pre and postnatal neuroimaging techniques, and molecular genetics have increased our understanding of the congenital malformation of the brain. Correct diagnosis of these malformations in regards to embryology, and molecular neurogenetics is of paramount importance to understand the inheritance pattern and risk of recurrence. Lesions detected on prenatal imaging require confirmation either with postnatal ultrasound and/or with MR imaging. With the advent of the faster (rapid) MRI techniques, which can be conducted without sedation, MRI is commonly used in the evaluation of congenital malformation of the brain. Based on neuroimaging pattern, the congenital malformations of the posterior fossa are classified into 4 main categories: (a) predominantly cerebellar, (b) cerebellar and brainstem, (c) predominantly brainstem, and (d) predominantly midbrain malformations.

Neurosurgical management of patients with neurocutaneous melanosis: a systematic review

OBJECTIVE

Neurocutaneous melanocytosis (NCM), also referred to as neurocutaneous melanosis, is a rare neurocutaneous disorder characterized by excess melanocytic proliferation in the skin, leptomeninges, and cranial parenchyma. NCM most often presents in pediatric patients within the first 2 years of life and is associated with high mortality due to proliferation of melanocytes in the brain. Prognosis is poor, as patients typically die within 3 years of symptom onset. Due to the rarity of NCM, there are no specific guidelines for management. The aims of this systematic review were to investigate approaches toward diagnosis and examine modern neurosurgical management of NCM.

METHODS

A systematic review was performed using the PubMed database between April and December 2021 to identify relevant articles using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Search criteria were created and checked independently among the authors. Inclusion criteria specified unique studies and case reports of NCM patients in which relevant neurosurgical management was considered and/or applied. Exclusion criteria included studies that did not report associated neurological diagnoses and neuroimaging findings, clinical reports without novel observations, and those unavailable in the English language. All articles that met the study inclusion criteria were included and analyzed.

RESULTS

A total of 26 extracted articles met inclusion criteria and were used for quantitative analysis, yielding a cumulative of 74 patients with NCM. These included 21 case reports, 1 case series, 2 retrospective cohort studies, 1 prospective cohort study, and 1 review. The mean patient age was 16.66 years (range 0.25–67 years), and most were male (76%). Seizures were the most frequently reported symptom (55%, 41/74 cases). Neurological diagnoses associated with NCM included epilepsy (45%, 33/74 cases), hydrocephalus (24%, 18/74 cases), Dandy-Walker malformation (24%, 18/74 cases), and primary CNS melanocytic tumors (23%, 17/74 cases). The most common surgical technique was CSF shunting (43%, 24/56 operations), with tethered cord release (4%, 2/56 operations) being the least frequently performed.

CONCLUSIONS

Current management of NCM includes CSF shunting to reduce intracranial pressure, surgery, chemotherapy, radiotherapy, immunotherapy, and palliative care. Neurosurgical intervention can aid in the diagnosis of NCM through tissue biopsy and resection of lesions with surgical decompression. Further evidence is required to establish the clinical outcomes of this rare entity and to describe the diverse spectrum of intracranial and intraspinal abnormalities present.

Genetics and Molecular Pathogenesis of Human Hydrocephalus

Hydrocephalus is a neurological disorder with an incidence of 80-125 per 100,000 live births in the United States. The molecular pathogenesis of this multidimensional disorder is complex and has both genetic and environmental influences. This review aims to discuss the genetic and molecular alterations described in human hydrocephalus, from well-characterized, heritable forms of hydrocephalus (e.g., X-linked hydrocephalus from L1CAM variants) to those affecting cilia motility and other complex pathologies such as neural tube defects and Dandy-Walker syndrome. Ventricular zone disruption is one key pattern among congenital and acquired forms of hydrocephalus, with abnormalities in cadherins, which mediate neuroepithelium/ependymal cell junctions and contribute to the pathogenesis and severity of the disease. Given the relationship between hydrocephalus pathogenesis and neurodevelopment, future research should elucidate the genetic and molecular mechanisms that regulate ventricular zone integrity and stem cell biology.

Trigeminal neuralgia caused by Dandy-walker malformation: A case report and systematic review of the literature

Trigeminal neuralgia is a pain condition that affects the face along the distribution of the trigeminal nerve and can be recurrent and chronic. Dandy-Walker syndrome is a complex congenital brain anomaly that occurs during embryonic development of the cerebellum and the fourth ventricle. It is characterized by inferior cerebellar vermis hypoplasia and incomplete formation of the fourth ventricle. Dandy-Walker Syndrome is associated with comorbid genetic conditions. It can include congenital heart defects, eye abnormalities, intellectual disability, congenital tumors, and other brain defects such as agenesis of the corpus callosum. However, associations of trigeminal neuralgia and Dandy Walker syndrome have been an infrequent entity. Herein, we report a case of a 23-year-old female patient that presented with complaints of severe left orofacial pain over two years. MRI evaluation was consistent with Dandy-Walker malformation findings that we suspect caused the compression in the trigeminal root entry zone that ultimately gave rise to the patient's symptoms.

The incidence of hydrocephalus among patients with and without spinal muscular atrophy (SMA): Results from a US electronic health records study

Background

The incidence of hydrocephalus in the spinal muscular atrophy (SMA) population relative to the general population is currently unknown. Since the approval of nusinersen, an intrathecally administered drug for SMA, a small number of hydrocephalus cases among nusinersen users have been reported. Currently, the incidence of hydrocephalus in untreated SMA patients is not available, thereby making it difficult to determine if hydrocephalus is a side effect of nusinersen or part of SMA’s natural history. This retrospective, matched cohort study used electronic health records (EHRs) to estimate and compare the incidence of hydrocephalus in both SMA patients and matched non-SMA controls in the time period prior to the approval of nusinersen.

Methods

The U.S. Optum® de-identified EHR database contains records for approximately 100 million persons. The current study period spanned January 1, 2007–December 22, 2016. Patients with SMA were identified by one or more International Classification of Diseases (ICD)-9 and/or ICD-10 codes for SMA appearing as primary, admission, or discharge diagnoses, without a pregnancy diagnostic code in the 1-year time before and after the first occurrence of SMA. The first occurrence of SMA defined the index date and non-SMA controls were matched to cases. Incident cases of hydrocephalus were identified with one or more ICD-9 and/or ICD-10 code for any type of hydrocephalus following the index date. Hydrocephalus incidence rates per person-months and the incidence rate ratio comparing SMA cases with non-SMA controls were calculated.

Results

There were 5354 SMA cases and an equal number of matched non-SMA controls. Incident hydrocephalus events were identified in 42 SMA cases and 9 non-SMA controls. Hydrocephalus incidence rates per 100,000 person-months were 15.5 (95% CI: 11.2–20.9) among SMA cases and 3.3 (95% CI: 1.5–6.3) among non-SMA controls. The incidence rate ratio was 4.7 (95% CI: 2.4–10.2).

Conclusions

Based on this retrospective analysis utilizing US EHR data, SMA patients had an approximately fourfold increased risk of hydrocephalus compared with non-SMA controls in the era preceding nusinersen treatment. This study may assist in properly evaluating adverse events in nusinersen-treated SMA patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01822-4.

Treatment strategies for hydrocephalus related to Dandy-Walker syndrome: evaluating procedure selection and success within the Hydrocephalus Clinical Research Network

OBJECTIVE

Treating Dandy-Walker syndrome-related hydrocephalus (DWSH) involves either a CSF shunt-based or endoscopic third ventriculostomy (ETV)-based procedure. However, comparative investigations are lacking. This study aimed to compare shunt-based and ETV-based treatment strategies utilizing archival data from the Hydrocephalus Clinical Research Network (HCRN) registry.

METHODS

A retrospective review of prospectively collected and maintained data on children with DWSH, available from the HCRN registry (14 sites, 2008-2018), was performed. The primary outcome was revision-free survival of the initial surgical intervention. The primary exposure was either shunt-based (i.e., cystoperitoneal shunt [CPS], ventriculoperitoneal shunt [VPS], and/or dual-compartment) or ETV-based (i.e., ETV alone or with choroid plexus cauterization [CPC]) initial surgical treatment. Primary analysis included multivariable Cox proportional hazards models.

RESULTS

Of 8400 HCRN patients, 151 (1.8%) had DWSH. Among these, the 102 patients who underwent shunt placement (79 VPSs, 16 CPSs, 3 other, and 4 multiple proximal catheter) were younger (6.6 vs 18.8 months, p < 0.001) and more frequently had 1 or more comorbidities (37.3% vs 14.3%, p = 0.005) than the 49 ETV-treated children (28 ETV-CPC). Fifty percent of the shunt-based and 51% of the ETV-based treatments failed. Notably, 100% (4/4) of the dual-compartment shunts failed. Adjusting for age, baseline ventricular size, and comorbidities, ETV-based treatment was not significantly associated with earlier failure compared with shunt-based treatment (HR for failure 1.32, 95% CI 0.77-2.26; p = 0.321). Complication rates were low: 4.9% and 6.1% (p = 0.715) for shunt- and ETV-based procedures, respectively. There was no difference in survival between ETV-CPC- and ETV-based treatment when adjusting for age (HR for failure 0.86, 95% CI 0.29-2.55, p = 0.783).

CONCLUSIONS

In this North American, multicenter, prospective database review, shunt-based and ETV-based primary treatment strategies of DWSH appear similarly durable. Pediatric neurosurgeons can reasonably consider ETV-based initial treatment given the similar durability and the low complication rate. However, given the observational nature of this study, the treating surgeon might need to consider subgroups that were too small for a separate analysis. Very young children with comorbidities were more commonly treated with shunts, and older children with fewer comorbidities were offered ETV-based treatment. Future studies may determine preoperative characteristics associated with ETV treatment success in this population.

Blake's pouch cyst: Prenatal diagnosis and management

Objective:

This study aimed to present the characteristic features of 19 patients who were diagnosed as having Blake’s pouch cyst (BPC) at our center.

Materials and Methods:

Nineteen patients diagnosed as BPC between 2015 and 2019 were included in this retrospective study. Follow-up examinations were performed using ultrasonography (US) every three weeks up to 35 weeks of gestation. Prenatal magnetic resonance imaging (MRI) was performed at the time of diagnosis or during follow-up in 13 patients. MRI or transfontanellar US was performed to confirm the diagnosis of BPC after delivery. Karyotype results of eight patients were recorded.

Results:

Isolated BPC was observed in 9 (47%) patients, and associated anomalies were detected in 10 (53%) patients, including seven (36%) with the central nervous system and four (21%) with cardiac anomalies. Two fetuses had abnormal karyotype analysis as trisomy 21 and 13. The MRI report of eight patients was “differential diagnosis required for Dandy-Walker complex” and only in five (26%) patients, it was reported to be compatible with BPC. Spontaneous resolution was seen in four patients. Postnatal MRI was performed in five patients, and transfontanellar US in two patients, and all MRI and US results were consistent with BPC. During the neonatal period, abnormal neurologic development was observed in four (21%) patients, and one (5%) died.

Conclusion:

Although the prognosis of isolated BPC is very good with healthy neurologic development until advanced ages, death in the early neonatal period and abnormal neurologic development may be observed depending on the condition of the associated anomalies.

Utility of genetic testing for prenatal presentations of hypophosphatasia

Hypophosphatasia (HPP) is a rare inherited disease affecting bone and dental mineralization due to loss-of-function mutations in the ALPL gene encoding the tissue nonspecific alkaline phosphatase (TNSALP). Prenatal benign HPP (PB HPP) is a rare form of HPP characterized by in utero skeletal manifestations that progressively improve during pregnancy but often still leave symptoms after birth. Because the prenatal context limits the diagnostic tools, the main difficulty for clinicians is to distinguish PB HPP from perinatal lethal HPP, the most severe form of HPP. We previously attempted to improve genotype phenotype correlation with the help of a new classification of variants based on functional testing. Among 46 perinatal cases detected in utero or in the neonatal period for whose ALPL variants could be classified, imaging alone was thought to clearly diagnose severe lethal HPP in 35 cases, while in 11 cases, imaging abnormalities could not distinguish between perinatal lethal and BP HPP. We show here that our classification of ALPL variants may improve the ability to distinguish between perinatal lethal and PB HPP in utero.

Severe symptomatic hyponatremia due to cerebral salt wasting syndrome in a patient with traumatic head injury and Dandy-Walker malformation of the brain

Cerebral salt wasting (CSW) is an uncommon cause of hyponatremia characterized by extracellular volume depletion, high urine sodium concentration and osmolality, and low serum uric acid concentration in association with central nervous system (CNS) disease. Distinguishing CSW from the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), a much more common form of hyponatremia in this setting, can be challenging because both present with identical laboratory features. However, treatment of CSW and SIADH differs, making a correct diagnosis important. Here we present a case of CSW in a 75-year-old man in whom severe hyponatremia and volume depletion were discovered in the setting of traumatic head injury and Dandy-Walker malformation of the brain, a rare congenital brain malformation. Treatment with intravenous normal saline and later oral salt supplementation and fludrocortisone was successful.

Diagnostic Approach to Cerebellar Hypoplasia

Cerebellar hypoplasia (CH) refers to a cerebellum of reduced volume with preserved shape. CH is associated with a broad heterogeneity in neuroradiologic features, etiologies, clinical characteristics, and neurodevelopmental outcomes, challenging physicians evaluating children with CH. Traditionally, neuroimaging has been a key tool to categorize CH based on the pattern of cerebellar involvement (e.g., hypoplasia of cerebellar vermis only vs. hypoplasia of both the vermis and cerebellar hemispheres) and the presence of associated brainstem and cerebral anomalies. With the advances in genetic technologies of the recent decade, many novel CH genes have been identified, and consequently, a constant updating of the literature and revision of the classification of cerebellar malformations are needed. Here, we review the current literature on CH. We propose a systematic approach to recognize specific neuroimaging patterns associated with CH, based on whether the CH is isolated or associated with posterior cerebrospinal fluid anomalies, specific brainstem or cerebellar malformations, brainstem hypoplasia with or without cortical migration anomalies, or dysplasia. The CH radiologic pattern and clinical assessment will allow the clinician to guide his investigations and genetic testing, give a more precise diagnosis, screen for associated comorbidities, and improve prognostication of associated neurodevelopmental outcomes.

Non-communicating hydrocephalus with a primary empty sella presenting with growth hormone deficiency and delayed puberty successfully treated by endoscopic third ventriculocisternostomy

The authors present the unusual case of a 15-year-old boy with a primary empty sella caused by non-communicating hydrocephalus due to fourth ventricle outflow obstruction whose secondary symptoms of growth hormone deficiency and delayed puberty were successfully treated by endoscopic third ventriculocisternostomy (ETV). Hypopituitarism occurs only rarely in cases of hydrocephalus; rarer still are cases where hypopituitarism is the sole symptom of hydrocephalus. A primary empty sella may indicate elevated intracranial pressure; if the cause is non-communicating hydrocephalus, ETV is indicated as the preferred treatment modality.

Prenatal sonographic diagnosis of Dandy-Walker malformation and type III lissencephaly: A novel association

Dandy-Walker malformation (DWM) may occur as part of Mendelian disorders such as Walker-Warburg and Meckel-Gruber syndromes. We report a novel association with type III lissencephaly in a 22-week male fetus. Ultrasound showed fetal akinesia deformation sequence, single umbilical artery, microlissencephaly, hydranencephaly with cerebral lamination, DWM, and pontocerebellar hypoplasia. These abnormalities were confirmed by magnetic resonance imaging and autopsy, which also revealed pulmonary and adrenal hypoplasia, common mesentery and bilateral uretero-pyelo-calyceal dilatation. Neuropathological examination showed brain calcifications and diffuse neuronal degeneration. We conclude that DWM may be a feature of type III lissencephaly and that this association can be easily diagnosed by ultrasound.

Lessons Learned From a Burn-Injured Pediatric Patient With Dandy-Walker Syndrome After Multiple Anesthetics: A Case Report

Dandy-Walker syndrome is a rare congenital brain malformation that requires unique anesthetic considerations. We present a rare case of an 18-month-old boy with Dandy-Walker syndrome presenting with 17% total body surface area burns undergoing multiple general anesthetics for both operative and bedside procedures. Numerous lessons were learned during multiple anesthetics, which influenced and guided our subsequent anesthetic management. The preoperative assessment, risk for respiratory apnea, opioid management, risk for laryngospasm, and postoperative care of patients with Dandy-Walker syndrome were all lessons learned.

Comparing the Efficiency of Two Treatment Methods of Hydrocephalus: Shunt Implantation and Endoscopic Third Ventriculostomy

Introduction:

Hydrocephalus is one of the most common diseases in children, and its treatment requires brain operation. However, the pathophysiology of the disease is very complicated and still unknown.

Methods:

Endoscopic Third Ventriculostomy (ETV) and Ventriculoperitoneal Shunt (VPS) implantation are among the common treatments of hydrocephalus. In this study, Cerebrospinal Fluid (CSF) hydrodynamic parameters and efficiency of the treatment methods were compared with numerical simulation and clinical follow-up of the treated patients.

Results:

Studies have shown that in patients under 19 years of age suffering from hydrocephalus related to a Posterior Fossa Brain Tumor (PFBT), the cumulative failure rate was 21% and 29% in ETV and VPS operation, respectively. At first, the ETV survival curve shows a sharp decrease and after two months it gets fixed while VPS curve makes a gradual decrease and reaches to a level lower than ETV curve after 5.7 months. Post-operative complications in ETV and VPS methods are 17% and 31%, respectively. In infants younger than 12 months with hydrocephalus due to congenital Aqueduct Stenosis (AS), and also in the elderly patients suffering from Normal Pressure Hydrocephalus (NPH), ETV is a better treatment option. Computer simulations show that the maximum CSF pressure is the most reliable hydrodynamic index for the evaluation of the treatment efficacy in these patients. After treatment by ETV and shunt methods, CSF pressure decreases about 9 and 5.3 times, respectively and 2.5 years after shunt implantation, this number returns to normal range.

Conclusion:

In infants with hydrocephalus, initial treatment by ETV was more reasonable than implanting the shunt. In adult with hydrocephalus, the initial failure in ETV occurred sooner compared to shunt therapy; however, ETV was more efficient.

Developmental Retrocerebellar Cysts: A New Classification for Neuroendoscopic Management and Systematic Review

OBJECTIVE

Posterior fossa cystic malformations are diversely classified with considerable overlap without therapeutic relevance. These cysts posterior to the cerebellum, presenting in children younger than 5 years, are labeled developmental retrocerebellar cysts (DRCCs) under a new classification in relation to neuroendoscopy.

METHODS

DRCC was categorized as type 0 for asymptomatic enlarged cistern magna and was not treated. Among symptomatic cases, cysts with a compressed fourth ventricle were labeled type 1, whereas cysts in continuity with the fourth ventricle were termed type 2. They were further categorized as subtype B if hydrocephalus was greater relative to the cyst, or otherwise as subtype A. The literature was reviewed according to PRISMA guidelines.

RESULTS

There were 13 children aged 3-48 months. Type 1A DRCC was noted in 5 patients, with onset before 6 months, 4 of whom (80%) had intracranial hypertension. All underwent suboccipital endoscopic deroofing and cisternostomy (SEDC), a new technique. Type 1B DRCC was seen in 2 patients, with onset at 8-9 months, who underwent endoscopic third ventriculostomy (ETV) + endoscopic ventriculocystostomy (EVC). Type 2A DRCC was observed in 4 patients, with onset at 5-47 months, who underwent SEDC. Type 2B DRCC was noted in 2 patients, with onset 6-8 months, who underwent ETV. With a mean follow-up of 32 months, all showed clinicoradiologic improvement. The application of our classification to other studies showed ETV/EVC to be successful in only 67% of type 1A DRCC and 72% of type 2A DRCC, compared with 100% efficacy of SEDC in our series.

CONCLUSIONS

This is probably the first ever endoscopic classification of pediatric posterior fossa cyts, elucidating pathophysiology, presentation, and treatment. Patients with type 1 DRCC present early because of extraneous compression. Among patients with type 2 DRCC, posterior fossa compliance determines the degree of hydrocephalus. The newly described SEDC seems more appropriate for types 1A and 2A DRCC. ETV is adequate in type 2B DRCC and effective with EVC in type 1B.

Neurocognitive profile of a man with Dandy-Walker malformation: Evidence of subtle cerebellar cognitive affective syndrome

Background: The Dandy-Walker Malformation (DWM) is a congenital birth malformation that is characterized by a triad of features: cerebellar dysgenesis, cystic dilation of the fourth ventricle, and an enlarged posterior fossa that displaces the dural sinuses and the tentorium. Despite this defining triad, clinical presentation can be highly heterogeneous in part due to severity of structural changes. To date, there been limited consideration of cognitive-behavioral symptoms of DWM in relation to nonmotor functions of the cerebellum, specifically cerebellar cognitive affective syndrome (CCAS).Method: In this case study, we describe the neuropsychological and behavioral profile of a 48-year-old man with DWM who was seen due to concerns, expressed solely by the patient's father, about his son's atypical housing, employment and social skills.Results: Neuropsychological test findings revealed high average intellect on standard intellectual measures (WAIS-IV), with stronger verbal (superior) than perceptual reasoning (average) skills. Across all cognitive domains, performance was generally within expectations, although bilateral fine motor skills were impaired. In contrast, he exhibited weaknesses on nontraditional neuropsychological measures assessing orbitofrontal-limbic circuitry, including reward sensitivity decision making and indices of threat-related emotional physiology.Conclusions: Through the use of traditional and nontraditional neuropsychological measures, subtle cognitive weaknesses in fronto-executive and affective regulation were illuminated and likely explain the patient's functional difficulties. Etiologically, these findings are consistent with the nonmotor functions of the cerebellum as described by CCAS.

Dandy-Walker malformation and syringomyelia: a rare association

PURPOSE

Dandy-Walker malformation is a rare condition due to imperforation of the Blake's pouch during intrauterine brain development, usually leading to early severe hydrocephalus. The association with holocord syringomyelia is rare, and from the Gardner's first report in 1957, only 23 cases have been described, mostly from autopsy series and pre-MRI period. Besides a worsening of clinical picture, its occurrence generates some concern about the best surgical treatment that varies widely among the literature reports.

METHODS

An 11-year-old girl with Dandy-Walker malformation presented with a holocord syrinx due to the herniation of the lower pole of the posterior fossa cyst through the foramen magnum.

RESULTS

After an unsuccessful shunt revision, she underwent a cystoperitoneal shunt with regression of the syrinx and of neurological symptoms at the 12-month follow-up.

CONCLUSIONS

Previous literature about pathogenesis, treatment, and follow-up is discussed and summarized.

[Dandy-Walker malformation]

The Dandy-Walker malformation is the most frequent cerebral malformation. It is defined by hypoplasia and upward rotation of the vermis cerebelli, a cystic enlargement of the fourth ventricle and in total an enlarged posterior fossa with cranially shifted position of the lateral sinus, tentorium and torcula herophili. This malformation was first described by Dandy and Blackfan in 1914 then supplemented again by Taggart and Walker in 1942. The current description as Dandy-Walker malformation was introduced in 1954 by Bender. In addition to these classical findings, the Dandy-Walker malformation is characterized by other abnormalities and malformations of the central nervous system (CNS) including agenesis of the corpus callosum, heterotopia, occipital meningocele, visual deficits and epilepsy. Neurogenetic and imaging examinations have led to a better understanding of this malformation.

The Most Common Comorbidities in Dandy-Walker Syndrome Patients: A Systematic Review of Case Reports

OBJECTIVE

Dandy-Walker syndrome (DWS) is a rare neurologic multi-entity malformation. This review aimed at reporting its main nonneurologic comorbidities.

METHODS

Following PRISMA guidelines, search in Medline was conducted (2000-2014, keyword: dandy-walker). Age, sex, country, DWS type, consanguinity or siblings with DWS, and recorded coexistent conditions (by ICD10 category) were extracted for 187 patients (46.5% male, 43% from Asia) from 168 case reports.

RESULTS

Diagnosis was most often set in <1 year old (40.6%) or >12 years old (27.8%). One-third of cases had a chromosomal abnormality or syndrome (n = 8 PHACE), 27% had a cardiovascular condition (n = 7 Patent Ductus Arteriosus), 24% had a disease of eye and ear (n = 9 cataract); most common malignancy was nephroblastoma (n = 8, all Asian). Almost one-fifth had a mental illness diagnosis; only 6.4% had mild or severe intellectual disability.

CONCLUSION

The spread of comorbidities calls for early diagnosis and multidisciplinary research and practice, especially as many cases remain clinically asymptomatic for years.

Antenatal manifestations of inborn errors of metabolism: autopsy findings suggestive of a metabolic disorder

This review highlights the importance of performing an autopsy when faced with fetal abortion or termination of pregnancy with suspicion of an inborn error of metabolism. Radiological, macroscopic and microscopic features found at autopsy as well as placental anomalies that can suggest such a diagnosis are detailed. The following metabolic disorders encountered in fetuses are discussed: lysosomal storage diseases, peroxisomal disorders, cholesterol synthesis disorders, congenital disorders of glycosylation, glycogenosis type IV, mitochondrial respiratory chain disorders, transaldolase deficiency, generalized arterial calcification of infancy, hypophosphatasia, arylsulfatase E deficiency, inborn errors of serine metabolism, asparagine synthetase deficiency, hyperphenylalaninemia, glutaric aciduria type I, non-ketotic hyperglycinemia, pyruvate dehydrogenase deficiency, pyruvate carboxylase deficiency, glutamine synthase deficiency, sulfite oxidase and molybdenum cofactor deficiency.

Congenital malformations of the brain and spine

In this chapter we briefly address the most common congenital brain and spinal anomalies as well as their most salient imaging, especially magnetic resonance, findings. Some of them, such as Chiari II, and open spinal defects, have become relatively rare due to their detection in utero and repair of the spinal malformation. Regardless of the type of brain anomaly, the most common clinical symptoms are mental retardation, hydrocephalus, and seizure; the latter two may need to be surgically and medically addressed. The most commonly found spinal congenital anomalies include the filum terminale lipoma which is generally asymptomatic and incidental and the caudal regression syndrome for which no primary treatment exists. Any spinal congenital anomaly may present in adulthood as a consequence of spinal cord tethering and/or development of syringomyelia.

Congenital brain malformations in the neonatal and early infancy period

Congenital brain malformations are a major cause of morbidity and mortality in pediatric patients who are younger than 2 years. Optimization of patient care requires accurate diagnosis, which can be challenging as congenital brain malformations include an extensive variety of anomalies. Radiologic imaging helps to identify the malformations and to guide management. Understanding radiologic findings necessitates knowledge of central nervous system embryogenesis. This review discusses the imaging of congenital brain malformations encountered in patients who are younger than 2 years in the context of brain development.

Diagnostic pitfall in antenatal manifestations of CPT II deficiency

Carnitine palmitoyltransferase II (CPT2) deficiency is a rare inborn error of mitochondrial fatty acid metabolism associated with various phenotypes. Whereas most patients present with postnatal signs of energetic failure affecting muscle and liver, a small subset of patients presents antenatal malformations including brain dysgenesis and neuronal migration defects. Here, we report recurrence of severe cerebral dysgenesis with Dandy-Walker malformation in three successive pregnancies and review previously reported antenatal cases. Interestingly, we also report that acylcarnitines profile, tested retrospectively on the amniotic fluid of last pregnancy, was not sensitive enough to allow reliable prenatal diagnosis of CPT2 deficiency. Finally, because fetuses affected by severe cerebral malformations are frequently aborted, CPT2 deficiency may be underestimated and fatty acid oxidation disorders should be considered when faced with a fetus with Dandy-Walker anomaly or another brain dysgenesis.

Inferior cerebellar hypoplasia resembling a Dandy-Walker-like malformation in purebred Eurasier dogs with familial non-progressive ataxia: a retrospective and prospective clinical cohort study

Cerebellar malformations can be inherited or caused by insults during cerebellar development. To date, only sporadic cases of cerebellar malformations have been reported in dogs, and the genetic background has remained obscure. Therefore, this study`s objective was to describe the clinical characteristics, imaging features and pedigree data of a familial cerebellar hypoplasia in purebred Eurasier dogs. A uniform cerebellar malformation characterized by consistent absence of the caudal portions of the cerebellar vermis and, to a lesser degree, the caudal portions of the cerebellar hemispheres in association with large retrocerebellar fluid accumulations was recognized in 14 closely related Eurasier dogs. Hydrocephalus was an additional feature in some dogs. All dogs displayed non-progressive ataxia, which had already been noted when the dogs were 5 – 6 weeks old. The severity of the ataxia varied between dogs, from mild truncal sway, subtle dysmetric gait, dysequilibrium and pelvic limb ataxia to severe cerebellar ataxia in puppies and episodic falling or rolling. Follow-up examinations in adult dogs showed improvement of the cerebellar ataxia and a still absent menace response. Epileptic seizures occurred in some dogs. The association of partial vermis agenesis with an enlarged fourth ventricle and an enlarged caudal (posterior) fossa resembled a Dandy-Walker-like malformation in some dogs. Pedigree analyses were consistent with autosomal recessive inheritance.

Dandy-walker malformation and down syndrome association: good developmental outcome and successful endoscopic treatment of hydrocephalus

The association of Down syndrome (DS) with Dandy Walker malformation (DWM) is extremely rare, with only 3 cases reported to date. All cases reported have shown a bad life expectancy and a bad developmental outcome. The present case reveals the possibility of a good prognosis. A 19-month-old male patient had successful endoscopic hydrocephalus treatment and a good developmental outcome. He probably had a better outcome because of good DS and DWM prognostic parameters. Our patient suffered from a DWM with vermis identification of 2 fissures and 3 lobes and a DS with a well-preserved tonus, which was not associated with other congenital systemic defects. We may conclude that the prognosis of DS-DWM association may separately depend on the degree of clinical and neurological involvement of each malformation.

Riding the wave of ependymal cilia: genetic susceptibility to hydrocephalus in primary ciliary dyskinesia

Congenital hydrocephalus is a relatively common and debilitating birth defect with several known physiological causes. Dysfunction of motile cilia on the ependymal cells that line the ventricular surface of the brain can result in hydrocephalus by hindering the proper flow of cerebrospinal fluid. As a result, hydrocephalus can be associated with primary ciliary dyskinesia, a rare pediatric syndrome resulting from defects in ciliary and flagellar motility. Although the prevalence of hydrocephalus in primary ciliary dyskinesia patients is low, it is a common hallmark of the disease in mouse models, suggesting that distinct genetic mechanisms underlie the differences in the development and physiology of human and mouse brains. Mouse models of primary ciliary dyskinesia reveal strain-specific differences in the appearance and severity of hydrocephalus, indicating the presence of genetic modifiers segregating in inbred strains. These models may provide valuable insight into the genetic mechanisms that regulate susceptibility to hydrocephalus under the conditions of ependymal ciliary dysfunction.

Neuroimaging of Dandy-Walker malformation: new concepts

Dandy-Walker malformation (DWM) is the most common human cerebellar malformation, characterized by hypoplasia of the cerebellar vermis, cystic dilation of the fourth ventricle, and an enlarged posterior fossa with upward displacement of the lateral sinuses, tentorium, and torcular. Although its pathogenesis is not completely understood, there are several genetic loci related to DWM as well as syndromic malformations and congenital infections. Dandy-Walker malformation is associated with other central nervous system abnormalities, including dysgenesis of corpus callosum, ectopic brain tissue, holoprosencephaly, and neural tube defects. Hydrocephalus plays an important role in the development of symptoms and neurological outcome in patients with DWM, and the aim of surgical treatment is usually the control of hydrocephalus and the posterior fossa cyst. Imaging modalities, especially magnetic resonance imaging, are crucial for the diagnosis of DWM and distinguishing this disorder from other cystic posterior fossa lesions. Persistent Blake's cyst is seen as a retrocerebellar fluid collection with cerebrospinal fluid signal intensity and a median line communication with the fourth ventricle, commonly associated with hydrocephalus. Mega cisterna magna presents as an extraaxial fluid collection posteroinferior to an intact cerebellum. Retrocerebellar arachnoid cysts frequently compress the cerebellar hemispheres and the fourth ventricle. Patients with DWM show an enlarged posterior fossa filled with a cystic structure that communicates freely with the fourth ventricle and hypoplastic vermis. Comprehension of hindbrain embryology is of utmost importance for understanding the cerebellar malformations, including DWM, and other related entities.