Neuroimaging of Dandy-Walker malformation: new concepts

Dandy-Walker malformation in an individual with ABL1 variant

Dandy-Walker malformation (DWM) is often sporadic, but there are a growing number of genetic disorders that have been associated with this condition. We present a female individual with a de novo variant in ABL1, c.734A>G (p.Y245), who was diagnosed prenatally with DWM. ABL1-related neurodevelopmental disorder was recently identified but brain malformations have not been well characterized to date. We reviewed the published literature and identified one additional individual with DWM and ABL1-related disorder, which suggests a possible association with this malformation.

Diagnosis and Treatment of Dandy-Walker Syndrome With Two Types of Ventriculoperitoneal (VP) Shunts: A Case Report

Dandy-Walker Syndrome (DWS) is a rare congenital neurological condition characterized by cerebellar and posterior fossa malformations, often presenting a variable clinical spectrum. Common complications include hydrocephalus, necessitating interventions like ventriculoperitoneal (VP) shunts, and endoscopic third ventriculostomy (ETV). We describe the case of a five-month-old infant conceived through in vitro fertilization (IVF), initially presenting with cold-like symptoms, later diagnosed with DWS. The patient underwent VP shunt placement for hydrocephalus management, with subsequent complications requiring shunt revisions and ETV. Vigilant monitoring and timely interventions were crucial for a favorable outcome, highlighting the challenges in diagnosing and managing DWS and the importance of tailored treatment strategies.

16p11.2 Microduplication Syndrome with Increased Fluid in the Cisterna: Coincidence or Phenotype Extension?

We report the first case of a child with 16p11.2 microduplication syndrome with increased fluid in the cisterna magna seen on magnetic resonance imaging (MRI). This finding may correspond to a Blake's Pouch Cyst (BPC) or a Mega Cisterna Magna (MCM), being impossible to differentiate through image examination. The molecular duplication was diagnosed using chromosomal microarray analysis with single nucleotide polymorphism (SNP). We review the clinical and neuroimaging features in published case reports in order to observe the findings described in the literature so far and present a skull three-dimensional model to contribute to a better understanding. Despite the variable expressivity of the syndrome being well known, there is no case described in the available literature that mentions the association of 16p11.2 microduplication and the presence of BPC or MCM seen in neuroimaging exams. This finding may represent an extension of the phenotype not yet reported or may present itself as a coincidence in a child with various malformations.

Meticulous and Early Understanding of Congenital Cranial Defects Can Save Lives

BACKGROUND

Omitting the early closure of the cranial sutures in newly born children is not an uncommon practice. We describe the natural history of several unrelated children and adults from two unrelated families. These children were born with variable clinical manifestations: craniofacial asymmetry, ocular proptosis, floppiness, and progressive deceleration in cognitive development. None of these children underwent a cranial sutures assessment. False diagnoses of positional plagiocephaly, neonatal thyrotoxicosis, congenital muscular atrophy, and hydrocephalus were given to the parents. This sort of malpractice was the reason behind a sequence of devastating pathological events that occurred in the lifetime of these children and adults.

MATERIAL AND METHODS

This was a multigenerational study of two unrelated families. In total, we studied three children (aged 7-19 years) and three adults (aged 40-52 years) from two families. The children from the first family were referred to our departments because of pre-pubertal scoliosis, kyphoscoliosis, and early-onset osteoarthritis. Reading the clinical histories of these children signified apparent clinical misconceptions. For instance, craniofacial asymmetry was misinterpreted as positional plagiocephaly and treated by means of helmet molding therapy. Ocular proptosis was given the false diagnosis of neonatal thyrotoxicosis. Floppiness (hypotonia) was misdiagnosed as congenital muscular dystrophy. The index case from the second family showed progressive deceleration in his cognitive development, associated with signs of increased intracranial pressure. The only diagnosis was Dandy-Walker malformation. We documented every patient in accordance with the clinical and radiological phenotypic characterizations. The genotype characterization followed accordingly.

RESULTS

All patients in family (I) manifested a phenotype consistent to a certain extent with the clinical phenotype of Shprintzen-Goldberg syndrome (SGS), though the intensity of spine deformities was greater than has been described in the literature. The second family showed a constellation of Marfanoid habitus, craniosynostosis, increased intracranial pressure, hydrocephalus, Dandy-Walker malformation, seizures, and intellectual disability. The overall clinical phenotype was consistent but not fully diagnostic of craniosynostosis-Dandy-Walker-malformation hydrocephalus syndrome. The early closure of the sutures was totally different from one patient to another, including the premature closure of the metopic, coronal, squamosal, and sagittal sutures. One patient from family (II) underwent the implementation of a shunt system at the age of 3 years, unfortunately passing over the pre-existing craniosynostosis. In addition to skeletal deformities, a history of seizures and severe intellectual disability was recorded. The proband underwent chromosomal karyotyping, the FISH test, and whole-exome sequencing.

CONCLUSION

The purpose of this study was fivefold. Firstly, to gain a meticulous understanding in order to differentiate between positional plagiocephaly, hypotonia, and congenital exophthalmos and their connections to abnormal craniofacial contours was and still is our first and foremost concern. Secondly, we aimed to characterize craniosynostosis, seizures, intellectual disabilities, and hydrocephalus associated with Marfanoid habitus, which were clearly demonstrated in our patients. Thirdly, we aimed to address the imperative for interpretations of clinical and radiological phenotypes and relate these tools to etiological understanding, which is an essential basis for diagnosis in the majority of long-term pediatric admissions. Fourthly, we aimed to assess the impacts of the missed early closure by the pediatricians and pediatric neurologists, which added a heavy pathological burden on these patients and their families. Fifthly, we aimed to identify whether early and diligent recognition can assist in cranial vault remodeling via surgical intervention to halt premature cranial suture fusions and can possibly alter the devastating course and the complications of the synostosed sutures.

NID1-related autosomal dominant Dandy-Walker malformation with occipital cephalocele in three generations

The combination of Dandy-Walker malformation and occipital cephalocele is a rare autosomal dominant condition, known as ADDWOC, and caused by mutations in NID1 or LAMC1. We present a three-generation family with variable manifestations of Dandy-Walker malformation and occipital cephalocele. They all have normal psychomotor development and lack neurological manifestations. Mutation analysis revealed a likely pathogenic missense variant in NID1 (c.3336T > G, p.Asn1112Lys), affecting an amino acid residue crucial in the nidogen/laminin interaction.

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.

Congenital Brain Malformations: An Integrated Diagnostic Approach

Congenital brain malformations are abnormalities present at birth that can result from developmental disruptions at various embryonic or fetal stages. The clinical presentation is nonspecific and can include developmental delay, hypotonia, and/or epilepsy. An informed combination of imaging and genetic testing enables early and accurate diagnosis and management planning. In this article, we provide a streamlined approach to radiologic phenotyping and genetic evaluation of brain malformations. We will review the clinical workflow for brain imaging and genetic testing with up-to-date ontologies and literature references. The organization of this article introduces a streamlined approach for imaging-based etiologic classification into malformative, destructive, and migrational abnormalities. Specific radiologic ontologies are then discussed in detail, with correlation of key neuroimaging features to embryology and molecular pathogenesis.

Dandy-Walker Malformation With Hydrocephalus: Diagnosis and Its Treatment

Dandy-Walker malformation is an uncommon type of brain malformation that occurs during embryonic development of the cerebellum and fourth ventricle. A case of Dandy-Walker malformation with hydrocephalus is being elaborated. The patient was operated on by the neurosurgery department and underwent ventriculoperitoneal shunting. The patient was stable and improved during the postoperative period.

Dandy-Walker syndrome with bilateral choanal atresia: A case report

INTRODUCTION

Dandy-Walker syndrome is a rare congenital brain malformation characterized by cerebellar vermis agenesis or hypoplasia, cystic dilatation of the fourth ventricle and a large posterior fossa causing upward displacement of tentorium and torcula. In this paper, we present a case of bilateral choanal atresia with Dandy-Walker Syndrome in a female newborn.

CASE PRESENTATION

We present a case of a female patient who was born at 38th weeks of gestation via emergency cesarean section due to non-reassuring cardiotocography and abnormal antenatal ultrasounds findings. The imaging revealed the presence of Dandy-walker malformation. The patient presented with cyanosis and respiratory distress. Bedside flexible nasoendoscopy revealed bilateral choanal atresia which is confirmed by computed tomography of sinuses. Endoscopic bilateral choanal atresia repair was performed. On postoperative follow up, nasal endoscopy showed bilateral intact flap and patent neochoana.

DISCUSSION AND CONCLUSION

Dandy-Walker syndrome is a congenital disorder that can be diagnosed prenatally. The syndrome is associated with multiple anomalies. However, there are few published reports of bilateral choanal atresia in Dandy-Walker Syndrome. Bilateral choanal atresia is considered a life-threatening condition in newborns that requires early surgical intervention.

Dandy-Walker Variant Associated with Bilateral Congenital Cataract

Dandy-Walker Syndrome (D-WS) is a rare disorder with an incidence of 1%–2% of all central nervous system anomalies. The diagnosis can be challenging, especially in the prenatal period. Here, we present an extremely rare case of D-WS associated with bilateral congenital cataracts. A 36 weeks and 6 days old male baby presented with a Dandy-Walker variant associated with bilateral congenital cataract. Ophthalmological examination revealed microphthalmos and congenital cataracts present in both eyes with sclerocornea, iris coloboma, and zone 3 retinopathy of prematurity involving only the right eye. However, the right eye was salvageable. Skull transillumination was negative with no cranial bruit. He was admitted to the neonatal intensive care unit with breathing difficulties, maintained SpO₂ with oxygen through prongs, and noninvasive continuous positive airway pressure for 7 days. He had two episodes of hypoglycemia with hypothermia. There was no significant finding in sepsis evaluation. The abdominal ultrasonography was normal. Echocardiogram was suggestive of patent foramen ovale. Mother's torch panel tested positive for cytomegalovirus immunoglobulin G antibodies. Magnetic resonance imaging brain suggested variant D-WS with dilation of cerebellar fossa and occipital lateral ventricle horn and lack of usual corpus callus structure. Intravenous antibiotics cefotaxime and amikacin were administered along with fluid supplementation. He was shifted to mother feed. The neonate was referred to the pediatric surgery department for further management.

Dandy-Walker Syndrome Associated with Scoliosis: Clinical Presentation, Preoperative Assessment, and Treatment

Dandy-Walker syndrome (DWS) affects the posterior cranial fossa resulting in characteristic dysmorphic facial and body features. Scoliosis is not typically reported as an extracranial manifestation of this condition. We present a 12-year-old female patient who developed a right thoracic scoliosis measuring 60° with increased lumbar lordosis. Scoliosis correction was indicated to alleviate back pain, improve cosmesis, and prevent respiratory complications. A multidisciplinary preoperative assessment included cardiac, respiratory, anaesthetic, and neurology reviews. She underwent a posterior spinal fusion from T2 to L3 with pedicle hook/screw and rod instrumentation and a combination of locally harvested autologous and allograft bone. This resulted in excellent deformity correction and a balanced spine in the coronal and sagittal planes. The patient made an uneventful recovery and returned gradually to her normal level of activities. She was monitored in clinic until she completed her growth (4 years after surgery); the satisfactory surgical outcome was maintained at follow-up and was associated with high patient satisfaction. Scoliosis can occur in children with DWS with resemblance to adolescent idiopathic scoliosis in regard to type of coronal deformity, age at presentation, surgical techniques, and postoperative recovery. Early identification of scoliosis in patients with DWS can allow preoperative planning and prompt surgical management in order to reduce the risk of significant morbidity which can occur if the scoliosis is allowed to deteriorate. Excellent deformity correction can be achieved and maintained beyond skeletal maturity in order to improve physical appearance, as well as preserve level of function and quality of life.

Abnormalities of the Fetal Central Nervous System: Prenatal US Diagnosis with Postnatal Correlation

Fetal central nervous system (CNS) abnormalities are second only to cardiac malformations in their frequency of occurrence. Early and accurate diagnosis at prenatal US is therefore essential, allowing improved prenatal counseling and facilitating appropriate referral. Thorough knowledge of normal intracranial anatomy and adoption of a logical sonographic approach can improve depiction of abnormal findings, leading to a more accurate differential diagnosis earlier in pregnancy. Four standard recommended views-transventricular, falx, cavum, and posterior fossa or transcerebellar views-provide an overview of fetal intracranial anatomy during the second trimester anatomy scan. Essential elements surveyed in the head and neck include the lateral cerebral ventricles, choroid plexus, midline falx, cavum septi pellucidi, cerebellum, cisterna magna, upper lip, and nuchal fold. CNS abnormalities can be organized into six main categories at prenatal US. Developmental anomalies include neural tube defects and neuronal migration disorders. Posterior fossa disorders include Dandy-Walker malformation variants and Chiari II malformation. Ventricular anomalies include aqueductal stenosis. Midline disorders include those on the spectrum of holoprosencephaly, agenesis of the corpus callosum, and septo-optic dysplasia. Vascular anomalies include vein of Galen malformations. Miscellaneous disorders include hydranencephaly, porencephaly, tumors, and intracranial hemorrhage. Correlation with postnatal MRI is helpful for confirmation and clarification of suspected diagnoses after birth. The authors discuss a standard US imaging approach to the fetal CNS and review cases in all categories of CNS malformations, providing postnatal MRI correlation when available.^©RSNA, 2020.

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.

Brain Malformations at All Ages: From Aunt Minnie to Zebras for General Radiologists

Congenital brain malformations comprise a spectrum of disorders that result from a variety of causes, including genetic abnormalities, ischemia, infections, and toxic exposures. Although most cases are discovered in infancy or childhood, clinically occult abnormalities may prove to be confounding, especially if first encountered later in life on imaging examinations obtained for other indications or in the context of superimposed pathology. This review article provides an overview of congenital brain malformations because they may be encountered at all ages for general radiologists.

Symptomatic foramen of Magendie arachnoid cyst in an elderly patient: The second case report in the literature

Background

Arachnoid cysts are benign extra-axial lesions corresponding to 1% of intracranial expansive lesions. They are usually incidental findings in asymptomatic patients. Most cases are congenital, and when symptomatic are diagnosed in childhood or adolescence. Symptomatic arachnoids cyst in elderly patients is very rare. This report documents the second case in the literature of a symptomatic elderly patient with an arachnoid cyst located in the foramen of Magendie.

Case Description

A 68-year-old male had weakness in the lower limbs, imbalance, and gait disturbance for 3 years, associated with frequent falls. The patient complained of paresthesia in the upper right limb and right hemiface. An magnetic resonance imaging showed a massive cystic lesion in the posterior fossa in the foramen of Magendie. A median suboccipital craniectomy was performed, and the cyst was removed.

Conclusion

This case report adds to the literature the second case of a patient with a symptomatic arachnoid cyst in the posterior fossa successfully treated by surgery.

Hemorrhagic Stroke in a Young Adult with Undiagnosed Asymptomatic Dandy-Walker Malformation

The Dandy–Walker Malformation was first described in 1914 by Dandy and Blackfan and is characterized by hypoplasia of the vermis, pseudocystic fourth ventricle, upward displacement of the tentorium, torcular and lateral sinuses, and anteroposterior enlargement of the posterior fossa. This syndrome commonly manifests as hydrocephalus in children, though rare adult cases have been reported. The literature reveals adult symptomatology including brainstem infarction, psychosis, and neuromuscular disease. Stroke is an exceptionally rare presentation of this malformation, with only one ischemic event reported in the literature. This case offers a rare opportunity for diagnosis in an adult presenting with a hemorrhagic stroke of the basal ganglia in an otherwise asymptomatic young adult male. To the best of our knowledge, this is the first reported case of a hemorrhagic stroke in an adult patient with Dandy–Walker Malformation.

A clinical diagnostic algorithm for early onset cerebellar ataxia

Early onset cerebellar Ataxia (EOAc) comprises a large group of rare heterogeneous disorders. Determination of the underlying etiology can be difficult given the broad differential diagnosis and the complexity of the genotype-phenotype relationships. This may change the diagnostic work-up into a time-consuming, costly and not always rewarding task. In this overview, the Childhood Ataxia and Cerebellar Group of the European Pediatric Neurology Society (CACG-EPNS) presents a diagnostic algorithm for EOAc patients. In seven consecutive steps, the algorithm leads the clinician through the diagnostic process, including EOA identification, application of the Inventory of Non-Ataxic Signs (INAS), consideration of the family history, neuro-imaging, laboratory investigations, genetic testing by array CGH and Next Generation Sequencing (NGS). In children with EOAc, this algorithm is intended to contribute to the diagnostic process and to allow uniform data entry in EOAc databases.

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.

Twenty years of misdiagnosis of schizophrenia in a patient with Dandy-Walker variant syndrome

Various case reports of patients with Dandy-Walker variant syndrome mimicking schizophrenia have been published in the last 20 years, suggesting that this neurodevelopment disorder should be part of the differential diagnosis for every patient with a first episode of psychosis. In this report, it is presented that a patient who was diagnosed and treated as a paranoid schizophrenic for 20 years and had four bone fractures secondary to ataxic gait impairment, before performing a neuroimaging examination that revealed Dandy-Walker variant syndrome.

[The case of completed pregnancy of the patient with Dandy-Walker malformation]

Dandy-Walker malformation is a rare disease of the central nervous system pathology (congenital malformations of the fossa cranii posterior). The key features of this syndrome are an enlargement of the fourth ventricle; complete absence of the cerebellar vermis, the posterior midline area of cerebellar cortex responsible for coordination of the axial musculature; and cyst formation near the internal base of the skull. Pregnant patients with Dandy-Walker malformation are at high risk and are managed by multidisciplinary teams including neurologists and obstetricians. We present a case report of full-term pregnancy and uncomplicated delivery in a women with Dandy-Walker malformation.

Scoliosis in Dandy-Walker syndrome: a case report and review of literature

This submission presents a case of scoliosis in a patient with established Dandy-Walker anomaly of the brain. A retrospective review of the patient's case notes was undertaken and the limited literature on this subject reviewed. The 13-year-old girl presented with a stiff right thoracic scoliosis typical of adolescent idiopathic scoliosis. The scoliotic segment also presented with significant lordosis. She had facial and truncal dysmorphism characteristic of Dandy-Walker complex and her brain images confirmed the diagnosis. She underwent scoliosis surgery by the posterior approach uneventfully. In conclusion scoliosis is hitherto unreported in the Dandy-Walker complex. The results of intervention appear satisfactory.

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.

Evaluation of the fetal cerebellum by magnetic resonance imaging

Obstetric protocols dictate that the fetal cerebellum should always be assessed during sonograms during pregnancy. For various reasons, including technical limitations or inconclusive sonographic findings, suspicion of cerebellar abnormalities is one of the most common indications for prenatal magnetic resonance imaging (MRI). Although sonography is the imaging technique of choice to assess the cerebellum, MRI shows the anatomy of the posterior fossa and abnormalities in the development of the fetal cerebellum in greater detail and thus enables a more accurate prenatal diagnosis. We describe and illustrate the normal anatomy of the fetal cerebellum on MRI as well as the different diseases that can affect its development. Moreover, we review the most appropriate terminology to define developmental abnormalities, their differential diagnoses, and the role of MRI in the prenatal evaluation of the posterior fossa.

Cerebellar and Brainstem Malformations

The frequency and importance of the evaluation of the posterior fossa have increased significantly over the past 20 years owing to advances in neuroimaging. Conventional and advanced neuroimaging techniques allow detailed evaluation of the complex anatomic structures within the posterior fossa. A wide spectrum of cerebellar and brainstem malformations has been shown. Familiarity with the spectrum of cerebellar and brainstem malformations and their well-defined diagnostic criteria is crucial for optimal therapy, an accurate prognosis, and correct genetic counseling. This article discusses cerebellar and brainstem malformations, with emphasis on neuroimaging findings (including diagnostic criteria), neurologic presentation, systemic involvement, prognosis, and recurrence.

Joubert syndrome: neuroimaging findings in 110 patients in correlation with cognitive function and genetic cause

BACKGROUND

Joubert syndrome is a clinically and genetically heterogeneous ciliopathy. Neuroimaging findings have not been systematically evaluated in a large cohort of patients with Joubert syndrome in correlation with molecular genetic cause and cognitive function.

METHODS

Brain MRI of 110 patients with Joubert syndrome was included in this study. A comprehensive evaluation of brain MRI studies for infratentorial and supratentorial morphological abnormalities was performed. Genetic cause was identified by whole-exome sequencing, and cognitive functions were assessed with age-appropriate neurocognitive tests in a subset of patients.

RESULTS

The cerebellar hemispheres were enlarged in 18% of the patients, mimicking macrocerebellum. The posterior fossa was enlarged in 42% of the patients, resembling Dandy-Walker malformation. Abnormalities of the brainstem, such as protuberance at the ventral contour of the midbrain, were present in 66% of the patients. Abnormalities of the supratentorial brain were present in approximately one-third of the patients, most commonly malrotation of the hippocampi. Mild ventriculomegaly, which typically did not require shunting, was present in 23% of the patients. No correlation between neuroimaging findings and molecular genetic cause was apparent. A novel predictor of outcome was identified; the more severe the degree of vermis hypoplasia, the worse the neurodevelopmental outcome was.

CONCLUSIONS

The spectrum of neuroimaging findings in Joubert syndrome is wide. Neuroimaging does not predict the genetic cause, but may predict the neurodevelopmental outcome. A high degree of vermis hypoplasia correlates with worse neurodevelopmental outcome. This finding is important for prognostic counselling in Joubert syndrome.

The Corpus Callosum and Forensic Issues-An Overview

The corpus callosum is a large central white matter tract that connects the right and left cerebral hemispheres. It permits placental mammals to have a more sophisticated interhemispheric integration of sensory cortices and allows communication between cortical and subcortical neurons. Search of the literature and the pathology archives at The University of Adelaide was undertaken to identify lesions and injuries within the corpus callosum that may have forensic significance. These include developmental/congenital lesions with agenesis/dysgenesis, vascular malformations, and lipomas; inherited syndromes such as neurofibromatosis; and acquired lesions involving trauma, neoplasia, demyelination, vascular conditions, infections, fat embolism, aging/dementia, and the effects of toxins. The finding of lesions within the corpus callosum should initiate careful examination of the adjacent brain and other organ systems for related phenomena as this may shed some light on the nature of the underlying condition, and also help to determine whether there are any forensic implications.

Magnetic Resonance Imaging of Malformations of Midbrain-Hindbrain

We aim to review the magnetic resonance imaging appearance of malformations of midbrain and hindbrain. These can be classified as predominantly cerebellar malformations, combined cerebellar and brain stem malformations, and predominantly brain stem malformations. The diagnostic criteria for the majority of these morphological malformations are based on neuroimaging findings. The predominantly cerebellar malformations include predominantly vermian hypoplasia seen in Dandy-Walker malformation and rhombencephalosynapsis, global cerebellar hypoplasia reported in lissencephaly and microlissencephaly, and unilateral cerebellar hypoplasia seen in PHACES, vanishing cerebellum, and cerebellar cleft. Cerebellar dysplasias are seen in Chudley-McCullough syndrome, associated with LAMA1 mutations and GPR56 mutations; Lhermitte-Duclos disease; and focal cerebellar dysplasias. Cerebellar hyperplasias are seen in megalencephaly-related syndromes and hemimegalencephaly with ipsilateral cerebellomegaly. Cerebellar and brain stem malformations include tubulinopathies, Joubert syndrome, cobblestone malformations, pontocerebellar hypoplasias, and congenital disorders of glycosylation type Ia. Predominantly brain stem malformations include congenital innervation dysgenesis syndrome, pontine tegmental cap dysplasia, diencephalic-mesencephalic junction dysplasia, disconnection syndrome, and pontine clefts.

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.