[Malformations of cortical development: what's new?] / Malformaciones del desarrollo cortical: ¿qué hay de nuevo?

Malformations of cortical development (MCDs) are structural abnormalities that disrupt the normal process of cortical development in utero. MCDs include microcephaly with simplified gyral pattern/microlyssencephaly, hemimegalencephaly, focal cortical dysplasia, lissencephaly, heterotopia, polymicrogyria, and schizencephaly. The debut of MCD can be with pharmacoresistant epilepsy, developmental delay, neurologic deficits, or cognitive impairment. The diagnostic pathway for MCDs is complex owing to wide variations in presentation and etiology. Although the definitive diagnosis of MCD depends on histopathology, neuroimages have an important role in this process. Furthermore, knowing the disturbance of the molecular pathway involved is important. Increased understanding of the molecular biology and recent advances in genetic testing have caused rapid growth in the knowledge of the genetic causes of MCDs, allowing for information on prognosis, recurrence risk, and prediction of treatment outcomes.

Las malformaciones del desarrollo cortical (MDC) son alteraciones estructurales que interrumpen el proceso normal de desarrollo cortical in utero. Se incluyen la microcefalia, con patrón giral simplificado/microlisencefalia, hemimegalencefalia, displasia cortical focal, lisencefalia, heterotopía, polimicrogiria y esquizencefalia. Se presentan con epilepsia farmacorresistente, retraso del desarrollo, déficit neurológico o compromiso cognitivo. El diagnóstico es complejo debido a la amplia variedad en su presentación y etiología. Aunque el diagnóstico definitivo es por anatomía patológica, las neuroimágenes cumplen un rol fundamental. Además, es sumamente importante conocer la alteración en el mecanismo molecular involucrado en la fisiopatogenia de la malformación. El creciente desarrollo de la biología molecular y de los estudios genéticos han mejorado el conocimiento de las causas genéticas de las MDC. Esto permitirá mejorar el pronóstico, consejo genético y probablemente las opciones terapéuticas.

Diagnóstico de malformación del desarrollo cortical en embarazo gemelar monocorial: reporte de caso / Diagnosis of malformation of the cortical development in a monochorial twin pregnancy: case report

Introducción: Las malformaciones del desarrollo cortical se deben a alteraciones en la migración del neuroblasto durante la formación de la corteza cerebral. Se desconoce su frecuencia en embarazos monocoriales. Objetivo: Reportar el caso de un embarazo monocorial con diagnóstico de malformación del desarrollo cortical en uno de los fetos y revisar la literatura referente a su diagnóstico y pronóstico. Método: Mujer de 19 años, embarazo monocorial biamniótico de 26 semanas, que acudió con estudio ecográfico y resonancia fetal que evidenció en uno de los fetos asimetría de los hemisferios cerebrales, hipoplasia de la cisura de Silvio izquierda con simplificación del patrón giral por focos de paquigiria y polimicrogiria, con confirmación posnatal de alteración en la migración neuronal asociada a hipoplasia vermiana. Resultados: Se encontraron en la literatura tres casos de embarazo múltiple monocorial con trastorno de la migración neuronal con recién nacidos vivos. Los hallazgos más comunes fueron microcefalia, lisencefalia e hipoplasia cerebelosa. Conclusiones: El diagnóstico prenatal del trastorno de la migración neuronal se realiza con ecografía y resonancia fetal. La más frecuente es la alteración de la migración neuronal tipo II. El pronóstico depende del tipo de alteración; sin embargo, la mayoría de los casos presentan trastornos epileptiformes con alteraciones del neurodesarrollo.

Introduction: Malformations of cortical development are the result from alterations in the neuroblast migration during the cerebral cortex formation. Its frequency in monochorial multiple pregnancies remains unknown. Objective: To report a case of monochorial multiple pregnancy with diagnosis of malformation of the cortical development in one of the fetuses. In addition, to review the literature regarding the diagnosis and prognosis of this entity. Method: A 19-year-old female with a monochorial diamniotic pregnancy of 26 weeks gestation, arrived with an ultrasound anatomy scan visit, and fetal magnetic resonance imaging, we detected asymmetry in the cerebral hemispheres one of the fetuses, hypoplasia of the left sulcus of Sylvius with simplification of the gyrus pattern due to clusters of pachygyria and polymicrogyria. Those findings were confirmed afterbirth, with a definite diagnosis of neuronal migration disorder associated with vermian hypoplasia. Results: Three cases of monochorial pregnancy with neuronal migration disorder with live newborn, common findings like microcephaly, lissencephaly and vermian hypoplasia. Conclusions: Prenatal diagnosis with neuronal migration disorder is done via ultrasound and magnetic resonance imaging. Neuronal migration disorders type II are the most common of them. Prognosis depends on the type of disorder; however, most patients have epileptiform activity and neurodevelopment impairment.

[Benefit of surgery in a case of negative motor focal epileptic seizures secondary to parietal cortical dysplasia]. / Beneficio de la cirugía en un caso de crisis epilépticas focales motoras negativas secundarias a displasia cortical parietal.

Focal atonic seizures are recognized rarely as ictal phenomena, they can correspond to both generalized epilepsy and focal epilepsy. The areas of the brain involved in the management of this type of seizure are: the negative motor area and the primary motor and primary somatosensory cortices, although the neurophysiology that generates them is still unclear. We present the case of a patient with focal atonic seizures in the left upper limb, refractory to drug treatment. Neuroimaging was performed, a parietal cortical lesion was diagnosed. A scalp Video EEG and then a Stereo EEG was performed, defining the epileptogenic area and its relationship with eloquent areas. Surgical resection of the lesion was performed, achieving complete seizure control.

Las crisis atónicas focales son poco reconocidas como fenómenos ictales, pueden corresponder tanto a una epilepsia generalizada como a una epilepsia focal. Las áreas del cerebro implicadas en la gestión de este tipo de crisis son: el área motora negativa y las cortezas motora primaria y somatosensitiva primaria, aunque aún la neurofisiología que las genera no está aclarada. Presentamos el caso de un paciente con crisis atónicas focales farmacorresistentes en miembro superior izquierdo. Se realizó resonancia de cerebro con diagnóstico de displasia cortical parietal, se monitoreó con video EEG de scalp y luego a video EEG con electrodos profundos. Se definieron el área epileptógena y su relación con áreas elocuentes, se realizó resección quirúrgica de la lesión, logrando el control completo de las crisis.

Magnetic resonance imaging findings and clinical characteristics in mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy in a predominantly adult cohort.

OBJECTIVE: We aimed to better characterize the magnetic resonance imaging (MRI) findings of mild malformation of cortical development with oligodendroglial hyperplasia (MOGHE), a rare clinicopathological entity associated with pharmacoresistance recently described in patients with frontal lobe epilepsy. METHODS: We studied 12 patients who underwent epilepsy surgery and whose surgical specimens showed histopathological findings of MOGHE, characterized by preserved cortical lamination, blurred gray-white matter interface due to increased number of oligodendrocytes, and heterotopic neurons in the white matter. The age at MRI evaluation ranged from 11 to 58 years, except for one 4.5-year-old patient. RESULTS: Following a detailed MRI analysis using an in-house protocol, we found abnormalities in all cases. The lesion was circumscribed in the frontal lobe in six (50%) and in the temporal lobe in three (25%) patients. In the remaining three patients (25%), the lesion was multilobar (frontotemporal and temporoparieto-occipital). Cortical thickening was mild in all patients, except in the 4.5-year-old patient, who had pronounced cortical thickening and white matter blurring. We also identified cortical/subcortical hyperintense T2/fluid-attenuated inversion recovery signal associated with gray/white matter blurring in all but one patient. When present, cleft cortical dimple, and deep sulci aided in localizing the lesion. Overall, the MRI findings were like those in focal cortical dysplasia (FCD) Type IIa. Surgical outcome was excellent in five patients (Engel Class I in 25% and II in 17%). The remaining seven patients (58%) had worthwhile seizure reduction (Engle Class III). Incomplete lesion resection was significantly associated with worse outcomes. SIGNIFICANCE: MRI findings associated with MOGHE are similar to those described in FCD Type IIa. Although more frequent in the frontal lobe, MOGHE also occurred in the temporal lobe or involved multiple lobes. Multilobar or extensive MOGHE MRI lesions are associated with less favorable surgical outcomes. Because this is a rare condition, multicenter studies are necessary to characterize MOGHE further.

Continuous epileptiform discharges during sleep as an evolutionary pattern in patients with congenital Zika virus syndrome.

Congenital Zika virus syndrome (CZVS) is associated with severe neurological deficits. Clinical characteristics of epilepsy and the electroencephalographic (EEG) pattern in CZVS were documented in infancy. In this study, we aimed to describe the EEG findings observed during the follow-up of children with CZVS. Seventy-six EEGs of 55 children (60% female; mean age = 50 months) with confirmed CZVS were analyzed, considering the background, interictal, and ictal epileptiform discharges. Continuous (or almost continuous) epileptiform discharges during non-rapid eye movement sleep were identified in 22 (40%) patients. In 20 (90.1%) patients, the pattern was symmetrical, with an anterior predominance of the epileptiform activity. All patients with this pattern had epilepsy, which was severe in 15 (68.2%) and demanded polytherapy in 19 (86.4%). Subcortical calcifications (77.3%) and multifocal EEGs (72.8%) in earlier ages occurred more often in patients with this pattern. Other unspecific interictal EEG patterns were focal epileptiform discharges in 23 (41.8%) and multifocal activity in six (10.9%). In CZVS, continuous (or almost continuous) epileptiform discharges during sleep emerge as a pattern after the second year of life. This was associated with severe and drug-resistant epilepsy, but not necessarily with an apparent regression. Subcortical calcifications and multifocal epileptiform discharges in infancy are associated with this pattern.

Neurological outcomes of congenital Zika syndrome in toddlers and preschoolers: a case series.

BACKGROUND: Congenital Zika syndrome causes a spectrum of neurological symptoms with varying effects on function that require different therapeutic strategies. To date, this spectrum of effects and its clinical implications have not been completely described. We describe the neurological examination findings in toddlers and preschoolers, including predominant symptom complexes and comorbidities. METHODS: This study is a case-series neurological evaluation of 75 children with congenital Zika syndrome in Campina Grande, Brazil. The study is part of a cohort of children with congenital Zika syndrome that started in 2015 and is still ongoing. Children with Zika virus infection detected during pregnancy (mothers exhibited rash and were followed and diagnosed by fetal ultrasound abnormalities or RT-PCR) or through microcephaly screening after birth, using Intergrowth 21 guidelines, were selected by laboratory and radiological criteria. Children were examined during a 10-day period in September, 2018, and underwent neurological interview, examination, and assessment of functional outcomes and comorbidities. Children were divided in groups of predominant corticospinal or neuromuscular clinical signs and the associations between these groups and clinical comorbidities were assessed. FINDINGS: All of the children recruited to the study from Nov 29, 2015 to Nov 30, 2017 had imaging correlates of congenital Zika syndrome. Children were assigned to groups depending on the signs exhibited, either corticospinal or neuromuscular, with or without dyskinetic signs. 75 children completed the evaluation, 38 (51%) girls and 37 (49%) boys. Median age was 33 months (range 26-40 months; IQR 29-34). Microcephaly was present at birth in 56 (75%) children, and 19 (25%) children were born with normal head circumference, 15 of whom later developed microcephaly. Neurological examination grouped four children as having isolated dyskinetic signs, 48 children were assigned to the corticospinal group and 23 into the neuromuscular group. Dyskinetic findings were present in 30 (40%) children, either alone (four [5%]) or combined with corticospinal (19 [40%] of 48) or neuromuscular (seven [30%] of 23) findings. Comorbidities were highly prevalent, and the neuromuscular group had worse functional outcomes, evaluated by gross motor function (p=0·026), manual abilities (p=0·0013), and communication function (p<0·0005) classification scales, than the corticospinal group, whereas pneumonia (p<0·0005) and urinary tract infections (p<0·0005) were more frequent in the corticospinal group. Cortical hyperexcitability was supported by several clinical correlates, such as early onset epilepsy, persistence of primitive reflexes, and dystonia. INTERPRETATION: We describe distinct neurological profiles in the congenital Zika syndrome spectrum, with functional outcomes tending to correlate with these groups. The clinical division of children based on the disease signs proposed here is supported by the literature on central and peripheral nervous system pathology in congenital Zika syndrome. The high prevalence of dyskinetic symptoms merits special attention. FUNDING: Brazilian National Council for Scientific and Technological Development and by the Coordination for the Improvement of Higher Education Personnel.

Early epilepsy in children with Zika-related microcephaly in a cohort in Recife, Brazil: Characteristics, electroencephalographic findings, and treatment response.

OBJECTIVE: To estimate the incidence of epilepsy in children with Zika-related microcephaly in the first 24 months of life; to characterize the associated clinical and electrographic findings; and to summarize the treatment responses. METHODS: We followed a cohort of children, born during the 2015-2016 Zika virus (ZIKV) epidemic in Brazil, with congenital microcephaly and evidence of congenital ZIKV infection on neuroimaging and/or laboratory testing. Neurological assessments were performed at ≤3, 6, 12, 15, 18, 21, and 24 months of life. Serial electroencephalograms were performed over the first 24 months. RESULTS: We evaluated 91 children, of whom 48 were female. In this study sample, the cumulative incidence of epilepsy was 71.4% in the first 24 months, and the main type of seizure was infantile spasms (83.1%). The highest incidence of seizures occurred between 3 and 9 months of age, and the risk remained high until 15 months of age. The incidence of infantile spasms peaked between 4 and 7 months and was followed by an increased incidence of focal epilepsy cases after 12 months of age. Neuroimaging results were available for all children, and 100% were abnormal. Cortical abnormalities were identified in 78.4% of the 74 children evaluated by computed tomography and 100% of the 53 children evaluated by magnetic resonance imaging. Overall, only 46.1% of the 65 children with epilepsy responded to treatment. The most commonly used medication was sodium valproate with or without benzodiazepines, levetiracetam, phenobarbital, and vigabatrin. SIGNIFICANCE: Zika-related microcephaly was associated with high risk of early epilepsy. Seizures typically began after the third month of life, usually as infantile spasms, with atypical electroencephalographic abnormalities. The seizure control rate was low. The onset of seizures in the second year was less frequent and, when it occurred, presented as focal epilepsy.

Visual analysis of automated segmentation in the diagnosis of focal cortical dysplasias with magnetic resonance imaging.

Focal cortical dysplasias (FCDs) are a frequent cause of epilepsy. It has been reported that up to 40% of them cannot be visualized with conventional magnetic resonance imaging (MRI). The main objective of this work was to evaluate by means of a retrospective descriptive observational study whether the automated brain segmentation is useful for detecting FCD. One hundred and fifty-five patients, who underwent surgery between the years 2009 and 2016, were reviewed. Twenty patients with FCD confirmed by histology and a preoperative segmentation study, with ages ranging from 3 to 43 years (14 men), were analyzed. Three expert neuroradiologists visually analyzed conventional and advanced MRI with automated segmentation. They were classified into positive and negative concerning visualization of FCD by consensus. Of the 20 patients evaluated with conventional MRI, 12 were positive for FCD. Of the negative studies for FCD with conventional MRI, 2 (25%) were positive when they were analyzed with automated segmentation. In 13 of the 20 patients (with positive segmentation for FCD), cortical thickening was observed in 5 (38.5%), while pseudothickening was observed in the rest of patients (8, 61.5%) in the anatomical region of the brain corresponding to the dysplasia. This work demonstrated that automated brain segmentation helps to increase detection of FCDs that are unable to be visualized in conventional MRI images.

[Malformations of cortical development and epilepsy]. / Epilepsias en las malformaciones del desarrollo cortical.

Around 15% of childhood epilepsies are resistant to antiepileptic drugs, 40% of which are caused by malformations of cortical development (MCD). The current classification scheme for MCD is based on the primary developmental steps of cell proliferation, neuronal migration, and cortical organization. Considering the clinic and molecular alterations, a classification based on main pathways disruption and imaging phenotype has been proposed. MCD were divided into four groups: megalencephaly and focal cerebral dysplasia; tubulinopathies and lissencephalies; polymicrogyria syndromes and heterotopia syndromes. More than 100 genes have been reported to be associated with different types of MCD. Genetic and biological mechanisms include different stages of cell cycle regulation - especially cell division -, apoptosis, cell-fate specification, cytoskeletal structure and function, neuronal migration, and basement-membrane function. The associated epileptic syndromes are varied ranging from early-onset epileptic encephalopathies to focal epilepsies. As MCD are common causes of refractory epilepsy, a prompt diagnosis and the development of different therapeutic options in order to improve the outcome of the patients are essential.

Alrededor del 15% de las epilepsias en pediatría son fármaco-resistentes y en el 40% de este grupo la etiología es una malformación del desarrollo cortical (MDC). El esquema de clasificación actual de las MDC se basa en las etapas primarias de desarrollo de la proliferación celular, migración neuronal y organización cortical. Teniendo en cuenta la clínica y las alteraciones moleculares, se propuso una clasificación basada en la disrupción de las vías principales y el fenotipo neurorradiológico. Se dividió a las MDC en cuatro grupos: la megalencefalia y las displasias corticales focales; las tubulinopatías y lisencefalias; el espectro de las polimicrogirias y las heterotopías. Hasta el momento, más de 100 genes han sido asociados con uno o más tipos de MDC. Los mecanismos biológicos y genéticos incluyen la regulación del ciclo celular en varios estadios, división celular), apoptosis, diferenciación celular, función y estructura del citoesqueleto, migración neuronal y membrana basal. El espectro de síndromes epilépticos asociados con las MDC es amplio e incluye desde encefalopatías epilépticas de comienzo temprano a epilepsias focales de debut más tardío. Teniendo en cuenta que la evolución de la epilepsia hacia la refractariedad en las MDC es importante, el diagnóstico precoz y la elección de la mejor opción terapéutica influirán en el pronóstico de los pacientes.

Epilepsias en las malformaciones del desarrollo cortical / Malformations of cortical development and epilepsy

Alrededor del 15% de las epilepsias en pediatría son fármaco-resistentes y en el 40% de este grupo la etiología es una malformación del desarrollo cortical (MDC). El esquema de clasificación actual de las MDC se basa en las etapas primarias de desarrollo de la proliferación celular, migración neuronal y organización cortical. Teniendo en cuenta la clínica y las alteraciones moleculares, se propuso una clasificación basada en la disrupción de las vías principales y el fenotipo neurorradiológico. Se dividió a las MDC en cuatro grupos: la megalencefalia y las displasias corticales focales; las tubulinopatías y lisencefalias; el espectro de las polimicrogirias y las heterotopías. Hasta el momento, más de 100 genes han sido asociados con uno o más tipos de MDC. Los mecanismos biológicos y genéticos incluyen la regulación del ciclo celular en varios estadios, división celular), apoptosis, diferenciación celular, función y estructura del citoesqueleto, migración neuronal y membrana basal. El espectro de síndromes epilépticos asociados con las MDC es amplio e incluye desde encefalopatías epilépticas de comienzo temprano a epilepsias focales de debut más tardío. Teniendo en cuenta que la evolución de la epilepsia hacia la refractariedad en las MDC es importante, el diagnóstico precoz y la elección de la mejor opción terapéutica influirán en el pronóstico de los pacientes.

Around 15% of childhood epilepsies are resistant to antiepileptic drugs, 40% of which are caused by malformations of cortical development (MCD). The current classification scheme for MCD is based on the primary developmental steps of cell proliferation, neuronal migration, and cortical organization. Considering the clinic and molecular alterations, a classification based on main pathways disruption and imaging phenotype has been proposed. MCD were divided into four groups: megalencephaly and focal cerebral dysplasia; tubulinopathies and lissencephalies; polymicrogyria syndromes and heterotopia syndromes. More than 100 genes have been reported to be associated with different types of MCD. Genetic and biological mechanisms include different stages of cell cycle regulation - especially cell division -, apoptosis, cell-fate specification, cytoskeletal structure and function, neuronal migration, and basement-membrane function. The associated epileptic syndromes are varied ranging from early-onset epileptic encephalopathies to focal epilepsies. As MCD are common causes of refractory epilepsy, a prompt diagnosis and the development of different therapeutic options in order to improve the outcome of the patients are essential.

ß-Tubulinopathy caused by a mutation of the TUBB2B gene: magnetic resonance imaging findings of the brain.

Patients with mutations in tubulin-related genes usually present with brain malformations, intellectual disability, epilepsy, microcephaly and ocular abnormalities. In these patients the diagnosis can be suggested by neuroimaging findings. We report a 5-year-old patient with characteristic magnetic resonance imaging findings including malformation of cortical development, fused basal ganglia, large head of the caudate nuclei, absent anterior limbs of the internal capsules, corpus callosum dysgenesis and dysplastic cerebellar vermis. Sequencing of the TUBB2B gene confirmed a heterozygous mutation: c. 260C>A (p. Pro87Gln).

Clinical Application of an Open-Source 3D Volume Rendering Software to Neurosurgical Approaches.

BACKGROUND: Preoperative recognition of the anatomic individualities of each patient can help to achieve more precise and less invasive approaches. It also may help to anticipate potential complications and intraoperative difficulties. Here we describe the use, accuracy, and precision of a free tool for planning microsurgical approaches using 3-dimensional (3D) reconstructions from magnetic resonance imaging (MRI). METHODS: We used the 3D volume rendering tool of a free open-source software program for 3D reconstruction of images of surgical sites obtained by MRI volumetric acquisition. We recorded anatomic reference points, such as the sulcus and gyrus, and vascularization patterns for intraoperative localization of lesions. Lesion locations were confirmed during surgery by intraoperative ultrasound and/or electrocorticography and later by postoperative MRI. RESULTS: Between August 2015 and September 2016, a total of 23 surgeries were performed using this technique for 9 low-grade gliomas, 7 high-grade gliomas, 4 cortical dysplasias, and 3 arteriovenous malformations. The technique helped delineate lesions with an overall accuracy of 2.6 ± 1.0 mm. 3D reconstructions were successfully performed in all patients, and images showed sulcus, gyrus, and venous patterns corresponding to the intraoperative images. All lesion areas were confirmed both intraoperatively and at the postoperative evaluation. CONCLUSIONS: With the technique described herein, it was possible to successfully perform 3D reconstruction of the cortical surface. This reconstruction tool may serve as an adjunct to neuronavigation systems or may be used alone when such a system is unavailable.

Nonmicrocephalic Infants with Congenital Zika Syndrome Suspected Only after Neuroimaging Evaluation Compared with Those with Microcephaly at Birth and Postnatally: How Large Is the Zika Virus "Iceberg"?

BACKGROUND AND PURPOSE: Although microcephaly is the most prominent feature of congenital Zika syndrome, a spectrum with less severe cases is starting to be recognized. Our aim was to review neuroimaging of infants to detect cases without microcephaly and compare them with those with microcephaly. MATERIALS AND METHODS: We retrospectively evaluated all neuroimaging (MR imaging/CT) of infants 1 year of age or younger. Patients with congenital Zika syndrome were divided into those with microcephaly at birth, postnatal microcephaly, and without microcephaly. Neuroimaging was compared among groups. RESULTS: Among 77 infants, 24.6% had congenital Zika syndrome (11.7% microcephaly at birth, 9.1% postnatal microcephaly, 3.9% without microcephaly). The postnatal microcephaly and without microcephaly groups showed statistically similar imaging findings. The microcephaly at birth compared with the group without microcephaly showed statistically significant differences for the following: reduced brain volume, calcifications outside the cortico-subcortical junctions, corpus callosum abnormalities, moderate-to-severe ventriculomegaly, an enlarged extra-axial space, an enlarged cisterna magna (all absent in those without microcephaly), and polymicrogyria (the only malformation present without microcephaly). There was a trend toward pachygyria (absent in groups without microcephaly). The group with microcephaly at birth compared with the group with postnatal microcephaly showed significant differences for simplified gyral pattern, calcifications outside the cortico-subcortical junctions, corpus callosum abnormalities, moderate-to-severe ventriculomegaly, and an enlarged extra-axial space. CONCLUSIONS: In microcephaly at birth, except for polymicrogyria, all patients showed abnormalities described in the literature. In postnatal microcephaly, the only abnormalities not seen were a simplified gyral pattern and calcifications outside the cortico-subcortical junction. Infants with normocephaly presented with asymmetric frontal polymicrogyria, calcifications in the cortico-subcortical junction, mild ventriculomegaly, and delayed myelination.