Sturge-Weber Syndrome Is Associated with Cortical Dysplasia ILAE Type IIIc and Excessive Hypertrophic Pyramidal Neurons in Brain Resections for Intractable Epilepsy

Neurological function and drug-refractory epilepsy in Sturge-Weber syndrome children: a retrospective analysis

Epilepsy in Sturge-Weber syndrome (SWS) is common, but drug-refractory epilepsy (DRE) in SWS has rarely been studied in children. We investigated the characteristics of epilepsy and risk factors for DRE in children with SWS. A retrospective study was conducted to analyze the clinical characteristics of children with SWS with epilepsy in our hospital from January 2013 to October 2022. Univariate and multivariate logistic analyses were performed to investigate the factors influencing DRE in children with SWS. A total of 35 SWS children with epilepsy were included (51% male; mean age of presentation 3.6 ± 0.5 years), 71% of children with SWS had their first seizure within the first year of life, and the most common type of seizure was focal seizure (77%). Eleven (31%) patients developed DRE. The median age of onset for the first seizure was 1.0 years and all these cases were of SWS type I. Multivariate logistic analysis revealed that stroke-like episodes and seizure clusters were risk factors for DRE in SWS children. A poor neurological function group was observed in twenty-five children with SWS. Status epilepticus was a risk factor that affected the neurological function of SWS children with epilepsy.  Conclusion: The study explored the epileptic features of children with SWS. The results revealed that stroke-like episodes and seizure clusters are risk factors for DRE in children with SWS. The occurrence of status epilepticus impacts the neurological function of SWS children with epilepsy. Thus, long-term follow-up is necessary to monitor outcomes. What is Known: • Sturge-Weber syndrome (SWS) is a rare neurocutaneous disorder, over 75% of children with SWS experience seizures, and 30-57% develop drug-refractory epilepsy (DRE), which leads to a poor outcome. • Drug-refractory epilepsy in SWS has been rarely studied in children, and the risk factors associated with DRE are unclear. What is New: • Clinical features of SWS children with drug-refractory epilepsy. • In SWS, stroke-like episodes and seizure clusters are risk factors of DRE, the occurrence of status epilepticus impacts the neurological function.

The specific DNA methylation landscape in focal cortical dysplasia ILAE type 3D

Focal Cortical Dysplasia (FCD) is a frequent cause of drug-resistant focal epilepsy in children and young adults. The international FCD classifications of 2011 and 2022 have identified several clinico-pathological subtypes, either occurring isolated, i.e., FCD ILAE Type 1 or 2, or in association with a principal cortical lesion, i.e., FCD Type 3. Here, we addressed the DNA methylation signature of a previously described new subtype of FCD 3D occurring in the occipital lobe of very young children and microscopically defined by neuronal cell loss in cortical layer 4. We studied the DNA methylation profile using 850 K BeadChip arrays in a retrospective cohort of 104 patients with FCD 1 A, 2 A, 2B, 3D, TLE without FCD, and 16 postmortem specimens without neurological disorders as controls, operated in China or Germany. DNA was extracted from formalin-fixed paraffin-embedded tissue blocks with microscopically confirmed lesions, and DNA methylation profiles were bioinformatically analyzed with a recently developed deep learning algorithm. Our results revealed a distinct position of FCD 3D in the DNA methylation map of common FCD subtypes, also different from non-FCD epilepsy surgery controls or non-epileptic postmortem controls. Within the FCD 3D cohort, the DNA methylation signature separated three histopathology subtypes, i.e., glial scarring around porencephalic cysts, loss of layer 4, and Rasmussen encephalitis. Differential methylation in FCD 3D with loss of layer 4 mapped explicitly to biological pathways related to neurodegeneration, biogenesis of the extracellular matrix (ECM) components, axon guidance, and regulation of the actin cytoskeleton. Our data suggest that DNA methylation signatures in cortical malformations are not only of diagnostic value but also phenotypically relevant, providing the molecular underpinnings of structural and histopathological features associated with epilepsy. Further studies will be necessary to confirm these results and clarify their functional relevance and epileptogenic potential in these difficult-to-treat children.

Seizure outcomes in children with Sturge-Weber syndrome undergoing epilepsy surgery: An individual participant data meta-analysis

BACKGROUND

A subpopulation of patients with Sturge-Weber syndrome (SWS) develop medically intractable epilepsy. There is a paucity of literature on preoperative factors that predict postoperative seizure outcomes in these patients. An individual participant data meta-analysis (IPDMA) was performed to discern preoperative variables associated with favorable seizure outcomes in pediatric SWS patients undergoing epilepsy surgery.

METHODS

PubMed, Cochrane, Web of Science, and Scopus were independently queried following PRISMA guidelines. Studies that reported seizure outcomes in individual pediatric SWS patients were selected. Preoperative demographic variables and disease characteristics were recorded and evaluated in a time-to-event fashion via Cox regression and Kaplan-Meier analysis with log-rank test.

RESULTS

A total of 18 studies with 108 patients were included for meta-analysis. Median age at seizure onset was 4.5 months, and 85 patients (78.7%) were seizure-free at last follow-up (median: 72 months). On multivariable Cox regression, no variables were independent predictors of post-operative seizure freedom duration, including the extent of hemispheric resection. There were also no differences in time-to-seizure recurrence on Kaplan-Meier analysis when comparing those treated with hemispheric surgery and those with less than hemispheric surgery (p = 0.52).

CONCLUSION

This IPDMA showed that both resective and hemispheric epilepsy surgery achieve favorable and comparable seizure outcomes in pediatric SWS patients. The best available evidence using IPD suggests that resective surgery may be an appropriate alternative to hemispheric epilepsy surgery in well-selected patients. Prospective multi-institutional studies with greater follow-up are warranted to further investigate predictors of seizure outcome in pediatric SWS patients.

Clinicopathological Analysis of Sturge-Weber Syndrome with Focal Cortical Dysplasia FCD IIIc

Objective: To investigate the clinicopathological features of children with Sturge-Weber syndrome and to analyze the correlation between the distribution area of leptomeningeal angiomatosis, the degree of cerebral cortical calcification, and the degree of cerebral atrophy associated with epileptic seizures. Methods: 10 children were diagnosed with SWS with FCD IIIc by histopathology and immunohistochemistry. Spearman correlation analysis was used to calculate the association of SWS with FCD IIIc and seizures in children. Results: The leptomeningeal angiomatosis area was markedly positively correlated with the degree of brain atrophy in 10 children with SWS (r = 0.783, p = 0.007). The distribution of leptomeningeal hemangiomatosis, the degree of cortical calcification, and brain atrophy were not significantly correlated with epilepsy. Conclusion: SWS may be accompanied by FCD IIIc. The more extensive the cerebral lobes of leptomeningeal angiomatosis in SWS, the more pronounced the brain atrophy.

The ILAE consensus classification of focal cortical dysplasia: An update proposed by an ad hoc task force of the ILAE diagnostic methods commission

Ongoing challenges in diagnosing focal cortical dysplasia (FCD) mandate continuous research and consensus agreement to improve disease definition and classification. An International League Against Epilepsy (ILAE) Task Force (TF) reviewed the FCD classification of 2011 to identify existing gaps and provide a timely update. The following methodology was applied to achieve this goal: a survey of published literature indexed with ((Focal Cortical Dysplasia) AND (epilepsy)) between 01/01/2012 and 06/30/2021 (n = 1349) in PubMed identified the knowledge gained since 2012 and new developments in the field. An online survey consulted the ILAE community about the current use of the FCD classification scheme with 367 people answering. The TF performed an iterative clinico-pathological and genetic agreement study to objectively measure the diagnostic gap in blood/brain samples from 22 patients suspicious for FCD and submitted to epilepsy surgery. The literature confirmed new molecular-genetic characterizations involving the mechanistic Target Of Rapamycin (mTOR) pathway in FCD type II (FCDII), and SLC35A2 in mild malformations of cortical development (mMCDs) with oligodendroglial hyperplasia (MOGHE). The electro-clinical-imaging phenotypes and surgical outcomes were better defined and validated for FCDII. Little new information was acquired on clinical, histopathological, or genetic characteristics of FCD type I (FCDI) and FCD type III (FCDIII). The survey identified mMCDs, FCDI, and genetic characterization as fields for improvement in an updated classification. Our iterative clinico-pathological and genetic agreement study confirmed the importance of immunohistochemical staining, neuroimaging, and genetic tests to improve the diagnostic yield. The TF proposes to include mMCDs, MOGHE, and "no definite FCD on histopathology" as new categories in the updated FCD classification. The histopathological classification can be further augmented by advanced neuroimaging and genetic studies to comprehensively diagnose FCD subtypes; these different levels should then be integrated into a multi-layered diagnostic scheme. This update may help to foster multidisciplinary efforts toward a better understanding of FCD and the development of novel targeted treatment options.

Variable histopathology features of neuronal dyslamination in the cerebral neocortex adjacent to epilepsy-associated vascular malformations suggest complex pathogenesis of focal cortical dysplasia ILAE type IIIc

Focal cortical dysplasia type IIIc (FCD‐IIIc) is histopathologically defined by the International League Against Epilepsy's classification scheme as abnormal cortical organization adjacent to epilepsy‐associated vascular malformations (VM). However, the incidence of FCD‐IIIc, its pathogenesis, or association with the epileptogenic condition remains to be clarified. We reviewed a retrospective series of surgical brain specimens from 14 epilepsy patients with leptomeningeal angiomatosis of Sturge‐Weber syndrome (LMA‐SWS; n = 6), cerebral cavernous malformations (CCM; n = 7), and an arteriovenous malformation (AVM; n = 1) to assess the histopathological spectrum of FCD‐IIIc patterns in VM. FCD‐IIIc was observed in all cases of LMA‐SWS and was designated as cortical pseudolaminar sclerosis (CPLS). CPLS showed a common pattern of horizontally organized layer abnormalities, including neuronal cell loss and astrogliosis, either manifesting predominantly in cortical layer (L) 3 extending variably to deeper areas with or without further extension to L2 and/or L4. Another pattern was more localized, targeting mainly L4 with extension to L3 and/or L5. Abnormal cortical layering characterized by a fusion of L2 and L3 or L4–L6 was also noted in two LMA‐SWS cases and the AVM case. No horizontal or vertical lamination abnormalities were observed in the specimens adjacent to the CCM, despite the presence of vascular congestion and dilated parenchymal veins in all VM. These findings suggest that FCD‐IIIc depends on the type of the VM and developmental timing. We further conclude that FCD‐IIIc represents a secondary lesion acquired during pre‐ and/or perinatal development rather than following a pathomechanism independent of LMA‐SWS. Further studies will be necessary to address the selective vulnerability of the developing cerebral neocortex in LMA‐SWS, including genetic, encephaloclastic, hemodynamic, or metabolic events.

Characteristics, surgical outcomes, and influential factors of epilepsy in Sturge-Weber syndrome

Few studies have reported the clinical presentation, surgical treatment, outcomes, and influential factors for patients with epilepsy and Sturge-Weber syndrome.

This large-scale retrospective study continuously enrolled 132 patients with Sturge-Weber syndrome and epilepsy from January 2008 to December 2018 at our hospital to analyze their characteristics. Among these patients, 90 underwent epilepsy surgery, and their postoperative 2-year follow-up seizure, cognitive, and motor functional outcomes were assessed and analyzed. Univariable and multivariable logistic analyses were conducted to explore the influential factors.

Among the Sturge-Weber syndrome patients for whom characteristics were analyzed (n = 132), 76.52% of patients had their first epileptic seizures within their first year of life. The risk factors for cognitive decline were seizure history≥2 years (adjusted odds ratio [aOR] = 3.829, 95% confidence interval [CI]: 1.810-9.021, p = 0.008), bilateral leptomeningeal angiomas (aOR = 3.173, 95% CI: 1.970-48.194, p = 0.013), age at onset < 1 year (aOR = 2.903, 95% CI: 1.230-6.514, p = 0.013), brain calcification (aOR = 2.375, 95% CI: 1.396-5.201, p = 0.021) and left leptomeningeal angiomas (aOR = 2.228, 95% CI: 1.351-32.571, p = 0.030). Of the patients who underwent epilepsy surgery (n = 90), 44 were subject to focal resection, and 46 underwent hemisphere surgery (19 anatomical hemispherectomies and 27 modified hemispherotomies). A postoperative seizure-free status, favorable cognitive outcomes, and favorable motor outcomes were achieved in 83.33%, 44.44%, and 43.33% of surgical patients, respectively. The modified hemispherotomy group had similar surgical outcomes, less intraoperative blood loss and shorter postoperative hospital stays than the anatomical hemispherectomy group. Regarding seizure outcomes, full resection (aOR = 11.115, 95% CI: 1.260-98.067, p = 0.020) and age at surgery < 2 years (aOR = 6.040, 95% CI: 1.444-73.367, p = 0.031) were positive influential factors for focal resection. Age at surgery < 2 years (aOR = 15.053, 95% CI: 1.050-215.899, p = 0.036) and infrequent seizures (aOR = 8.426, 95% CI: 1.086-87.442, p = 0.042; monthly vs. weekly) were positive influential factors for hemisphere surgery.

In conclusion, epilepsy surgery resulted in a good postoperative seizure-free rate and favorable cognitive and motor functional outcomes and showed acceptable safety for patients with epilepsy and Sturge-Weber syndrome. Modified hemispherotomy is a less invasive and safer type of hemisphere surgery than traditional anatomic hemispherectomy with similar surgical outcomes. Early surgery may be helpful to achieve better seizure outcomes and cognitive protection, while the risk of surgery for young children should also be considered.

The role of adenosine A1 receptor agonist in adenosine augmentation therapy for patients with refractory epilepsy in Sturge-Weber syndrome: An in vitro electrophysiological study

PURPOSES

This study was to further explore the adenosine dysfunction in refractory epilepsy in Sturge-Weber Syndrome (SWS), to evaluate the neuronal-level effect of the A1 receptor (A1R) agonist on both excitatory pyramidal neurons and inhibitory interneurons, to discuss the possibility of adenosine augmentation therapy (AAT) using A1R agonist for treating refractory epilepsy in SWS.

MATERIALS AND METHODS

The intrinsic excitatory properties of pyramidal cells (PCs) and fast-spiking (FS) interneurons from human brain tissues with SWS cases and malformations of cortical development (MCD) cases were compared using electrophysiology. With application of either A1R agonist or antagonist, the neuronal-level effect of A1R agonist was evaluated in vitro in PCs and FS interneurons from SWS cases and MCD cases.

RESULTS

No significant difference of passive excitatory properties of PCs and FS interneurons was found between SWS cases and MCD cases. In terms of the neuronal-level effect of A1R agonist, with 22.88 ± 1.12% percentage of decreased frequency, FS interneurons showed relatively highest sensitivity of A1R agonist application, compared with PCs from SWS cases and FS interneurons and PCs from MCD cases.

CONCLUSION

Our results supported the potential of AATs using A1R agonist to be a novel therapy for reducing life burden from patients with refractory epilepsy in SWS, with application to epileptic generation region but not propagation region.

Physical and Family History Variables Associated With Neurological and Cognitive Development in Sturge-Weber Syndrome

BACKGROUND

Sturge-Weber syndrome (SWS) is caused by a somatic mutation in GNAQ leading to capillary venous malformations in the brain presenting with various neurological, ophthalmic, and cognitive symptoms of variable severity. This clinical variability makes accurate prognosis difficult. We hypothesized that the greater extent of physical factors (extent of skin, eye, and brain involvement), presence of possible genetic factors (gender and family history), and age of seizure onset may be associated with greater symptom severity and need for surgery in patients with SWS.

METHODS

The questionnaire was collected from 277 participants (age: two months to 66 years) with SWS brain involvement at seven US sites.

RESULTS

Bilateral brain involvement was associated with both learning disorder and intellectual disability, whereas port-wine birthmark extent was associated with epilepsy and an increased likelihood of glaucoma surgery. Subjects with family history of vascular birthmarks were also more likely to report symptomatic strokes, and family history of seizures was associated with earlier seizure onset. Learning disorder, intellectual disability, strokelike episodes, symptomatic stroke, hemiparesis, visual field deficit, and brain surgery were all significantly associated with earlier onset of seizures.

CONCLUSION

The extent of brain and skin involvement in SWS, as well as the age of seizure onset, affect prognosis. Other genetic factors, particularly variants involved in vascular development and epilepsy, may also contribute to neurological prognosis, and further study is needed.

Upregulation of Rho7 in the temporal lobe tissue of humans with intractable epilepsy

Patients with intractable epilepsy (IE) exhibit an increased risk of premature death, psychosocial dysfunction and decreasing quality of life. The present study aimed to investigate the alteration in the expression of Rho7 in brain tissue from patients with IE, and to examine the association between Rho7 protein expression and IE. Temporal lobe samples were collected from the temporal lobes of 33 patients with IE patients and 10 age‑ and gender‑matched histologically healthy controls. Immunohistochemical staining was conducted to assess the number of Rho7‑positive cells. In addition, double‑label immunofluorescent staining was performed to examine the cellular localization of Rho7. The protein expression of Rho7 was examined using western blotting. Marked immunoreactivity for Rho7 was detected in the IE group, while faint and scattered immunoreactive staining was observed in the control group. The count of Rho7 positive cells in the IE patients was significantly increased compared with the control subjects (23.47±3.9% vs. 12.09±1.05%; P<0.01). Double‑label immunofluorescent staining indicated that Rho7 was primarily expressed in the cell membrane and cytoplasm, and colocalized with neuron‑specific enolase. Western blot analysis demonstrated that the expression of Rho7 in the IE group was significantly increased compared with the control group (0.41±0.031 vs. 0.25±0.025; P<0.01). The results of the present study demonstrated that upregulation of Rho7 immunoreactivity occurs in the brains of patients with IE, suggesting that Rho7 may be associated with the progression of IE or act as a potential treatment target.

GNAQ Mutation in the Venous Vascular Malformation and Underlying Brain Tissue in Sturge-Weber Syndrome

The recent identification of the somatic GNAQ mutation (c.548G > A) provides insight into the pathogenesis of Sturge–Weber syndrome (SWS). Although the primary SWS brain pathology is the leptomeningeal angiomatosis (LMA), cerebral cortical and white matter abnormalities play a prominent role in the disease manifestations. In some cases, SWS brain involvement is present even without detectable LMA on magnetic resonance imaging (MRI). To expand our understanding of the etiology of SWS brain pathology, surgical SWS brain specimens from nine children (age: 0.8–7.5 years) were carefully separated into LMA and (non-LMA) brain tissue; the latter did not contain any vascular malformation. A custom Competitive Allele-Specific TaqMan PCR (castPCR) assay to detect the mutation in GNAQ was performed in these separated specimens. The mutation was present in all nine LMA and seven of the nine non-LMA brain tissues. LMA tissues were significantly enriched by the mutation, as compared with non-LMA brain (mean: 7.2 ± 2.1% and 1.2 ± 0.4%, respectively; p = 0.008). These results demonstrate that the somatic GNAQ mutation in SWS is not confined to the venous vascular malformation but can directly (although less severely) affect underlying brain parenchyma, not directly affected by LMA, and possibly contribute to SWS brain pathology. Future studies should identify the specific cell type(s) affected by the mutation in the SWS-affected brain parenchyma.

A distinct clinicopathological variant of focal cortical dysplasia IIId characterized by loss of layer 4 in the occipital lobe in 12 children with remote hypoxic-ischemic injury

OBJECTIVE

In 2011, the International League Against Epilepsy (ILAE) proposed a consensus classification system of focal cortical dysplasia (FCD) to distinguish clinicopathological subtypes, for example, "isolated" FCD type Ia-c and IIa-b, versus "associated" FCD type IIIa-d. The histopathological differentiation of FCD type I and III variants remains, however, a challenging issue in everyday practice. We present a unique histopathological pattern in patients with difficult-to-diagnose FCD, which highlights this dilemma, but also helps to refine the current ILAE classification scheme of FCD.

METHODS

We present a retrospective series of 11 male and one female patient with early onset pharmacoresistant epilepsy of the posterior quadrant (mean age at seizure onset = 4.6 years). All surgical specimens were reviewed. Clinical histories were retrieved and extracted from archival patient files.

RESULTS

Microscopic inspection revealed abnormalities in cortical architecture with complete loss of layer 4 in all surgical samples of the occipital lobe, as confirmed by semiquantitative measurements (p < 0.01). Clinical history reported early transient hypoxic condition in nine patients (75%). Magnetic resonance imaging (MRI) revealed abnormal signals in the occipital lobe in all patients, and signal changes suggestive of subcortical encephalomalacia were found in seven patients. Surgical treatment achieved favorable seizure control (Engel class I and II) in seven patients with an available follow-up period of 6.1 years.

SIGNIFICANCE

Prominent disorganization of cortical layering and lack of any other microscopically visible principle lesion in the surgical specimen would result in this neuropathological pattern hitherto being classified as FCD ILAE type Ib. However, perinatal hypoxia with distinctive MRI changes suggested primarily a hypoxemic lesion and acquired pathomechanism of neuronal cell loss in the occipital lobe of our patient series. We propose, therefore, classifying this distinctive clinicopathological pattern as a separate variant of FCD ILAE type IIId.

Epilepsy surgery in patients with autism

OBJECTIVE The purpose of this study was to report outcomes of epilepsy surgery in 56 consecutive patients with autism spectrum disorder. METHODS Medical records of 56 consecutive patients with autism who underwent epilepsy surgery were reviewed with regard to clinical characteristics, surgical management, postoperative seizure control, and behavioral changes. RESULTS Of the 56 patients with autism, 39 were male, 45 were severely autistic, 27 had a history of clinically significant levels of aggression and other disruptive behaviors, and 30 were considered nonverbal at baseline. Etiology of the epilepsy was known in 32 cases, and included structural lesions, medical history, and developmental and genetic factors. Twenty-nine patients underwent resective treatments (in 8 cases combined with palliative procedures), 24 patients had only palliative treatments, and 3 patients had only subdural electroencephalography. Eighteen of the 56 patients had more than one operation. The mean age at surgery was 11 ± 6.5 years (range 1.5-35 years). At a mean follow-up of 47 ± 30 months (range 2-117 months), seizure outcomes included 20 Engel Class I, 12 Engel Class II, 18 Engel Class III, and 3 Engel Class IV cases. The age and follow-up times are stated as the mean ± SD. Three patients were able to discontinue all antiepileptic drugs (AEDs). Aggression and other aberrant behaviors observed in the clinical setting improved in 24 patients. According to caregivers, most patients also experienced some degree of improvement in daily social and cognitive function. Three patients had no functional or behavioral changes associated with seizure reduction, and 2 patients experienced worsening of seizures and behavioral symptoms. CONCLUSIONS Epilepsy surgery in patients with autism is feasible, with no indication that the comorbidity of autism should preclude a good outcome. Resective and palliative treatments brought seizure freedom or seizure reduction to the majority of patients, although one-third of the patients in this study required more than one procedure to achieve worthwhile improvement in the long term, and few patients were able to discontinue all AEDs. The number of palliative procedures performed, the need for multiple interventions, and continued use of AEDs highlight the complex etiology of epilepsy in patients with autism spectrum disorder. These considerations underscore the need for continued analysis, review, and reporting of surgical outcomes in patients with autism, which may aid in better identification and management of surgical candidates. The reduction in aberrant behaviors observed in this series suggests that some behaviors previously attributed to autism may be associated with intractable epilepsy, and further highlights the need for systematic evaluation of the relationship between the symptoms of autism and refractory seizures.

Neuropathology of epilepsy

Epilepsy is one of the most common neurologic disorders, affecting about 50 million people worldwide. The disease is characterized by recurrent seizures, which are due to aberrant neuronal networks resulting in synchronous discharges. The term epilepsy encompasses a large spectrum of syndromes and diseases with different etiopathogenesis. The recent development of imaging and epilepsy surgery techniques is now enabling the identification of structural abnormalities that are part of the epileptic network, and the removal of these lesions may result in control of seizures. Access of this clinically well-characterized neurosurgical material has provided neuropathologists with the opportunity to study a variety of structural brain abnormalities associated with epilepsy, by combining traditional routine histopathologic methods with molecular genetics and functional analysis of the resected tissue. This approach has contributed greatly to a better diagnosis and classification of these structural lesions, and has provided important new insights into their pathogenesis and epileptogenesis. The present chapter provides a detailed description of the large spectrum of histopathologic findings encountered in epilepsy surgery patients, addressing in particular the nonneoplastic pathologies, including hippocampal sclerosis, malformations of cortical development, Sturge-Weber syndrome, and Rasmussen encephalitis, and reviews current knowledge regarding the underlying molecular pathomechanisms and cellular mechanisms mediating hyperexcitability.

Sturge-Weber Syndrome: Brain Magnetic Resonance Imaging and Neuropathology Findings

BACKGROUND

We describe the brain magnetic resonance imaging (MRI) abnormalities and neuropathologic findings of patients with Sturge-Weber syndrome and medically refractory epilepsy.

METHODS

We reviewed the clinical features, preoperative MRI studies, and pathologic findings of all patients with Sturge-Weber syndrome who underwent excisional surgery for intractable epilepsy at Boston Children's Hospital between 1993 and 2011.

RESULTS

Eleven patients (male/female = 4/7) with Sturge-Weber syndrome were identified who underwent surgery for intractable epilepsy (mean age 13 ± 6.2 months), including hemispherectomy (n = 10) and focal cortical resection (n = 1). Mean age at seizure onset was 15 ± 11 weeks. Fifty-five percent (n = 6) of patients exhibited two different types of seizures, and 18% (n = 2) had three types of seizures. Focal clonic seizures were the most common type, occurring in nine patients; apnea was the second most common, occurring in four patients. Brain MRIs were reviewed in five patients. Histopathologic examination revealed varied degrees of cortical morphologic anomaly in seven of 11 patients. Overall, there were no abnormalities in the MRIs that corresponded directly with the pathologic findings except in one patient with polymicrogyria.

CONCLUSIONS

In spite of pathologic findings of cortical anomalies in varied degrees, these findings could not be readily detected on brain MRIs. The failure to detect focal cortical dysplasia on MRIs may be attributable to the subtle microscopic nature of the abnormalities; in some of the older individuals, the imaging studies available for review were done during an advanced stage of the disease.

Epileptogenesis in neurocutaneous disorders with focus in Sturge Weber syndrome

Epilepsy is a major morbidity in Sturge Weber syndrome, a segmental vascular neurocutaneous disorder classically associated with facial angiomas, glaucoma, and leptomeningeal capillary-venous type vascular malformations. The extent of the latter correlates with neurological outcome. Post-zygotic mosaicism for the activating mutation p.R183Q of the GNAQ gene has been identified as the major cause.  GNAQ encodes for an alpha subunit of a heterotrimeric G protein critical to blood vessel development. The earlier the timing of the mutation in development, the more severe the involvement, e.g. from isolated port-wine stains to the full syndrome. The strongest predictors of adverse outcomes are MRI and the presence of angiomas involving any part of the forehead, delineated inferiorly from the outer canthus of the eye to the top of the ear, and including the upper eyelid.  The neurological course may be progressive and the typical constellation of symptoms is focal onset seizures, hemiparesis, headache, stroke-like episodes, behavior problems, intellectual disability, and visual field deficits. Antiseizure medications are effective in about half of patients. The presence of localized seizures, focal neurological deficits, and drug resistant epilepsy indicate epilepsy surgical evaluation. Earlier seizure onset, i.e. before six months of age, is associated with a more severe course with significant residual deficits. Factors contributing to epileptogenesis include decreased brain tissue perfusion due to abnormal venous drainage, anoxic injury contributing to cerebral calcification, breakdown of the blood-brain barrier, and the presence of developmental cortical malformations. Pre-symptomatic prophylactic treatment may be a future option to modify the course of the disease including the associated epileptogenesis.

Imaging increased glutamate in children with Sturge-Weber syndrome: Association with epilepsy severity

BACKGROUND

Sturge-Weber syndrome (SWS) is strongly associated with epilepsy. Brain tissue studies have suggested that epileptic activity in SWS is driven by glutamatergic synaptic activity. Here, we used proton magnetic resonance spectroscopic imaging (MRSI) to test if glutamate (GLU) concentrations are increased in the affected hemisphere and if such increases are associated with severity of epilepsy in children with SWS. We also studied the metabolic correlates of MRSI abnormalities, using glucose positron emission tomography (PET) imaging.

METHODS

3T MRI and glucose PET were performed in 10 children (age: 7-78 months) with unilateral SWS and a history of epilepsy. MRSI data were acquired from the affected (ipsilateral) and non-affected (contralateral) hemispheres. GLU, N-acetyl-aspartate (NAA) and creatine (Cr) were quantified in multiple voxels; GLU/Cr and NAA/Cr ratios were calculated and compared to seizure frequency as well as glucose PET findings.

RESULTS

The highest GLU/Cr ratios were found in the affected hemisphere in all children except one with severe atrophy. The maximum ipsilateral/contralateral GLU/Cr ratios ranged between 1.0 and 2.5 (mean: 1.6). Mean ipsilateral/contralateral GLU/Cr ratios were highest in the youngest children and showed a strong positive correlation with clinical seizure frequency scores assessed at the time of the scan (r=0.88, p=0.001) and also at follow-up (up to 1 year, r=0.80, p=0.009). GLU increases in the affected hemisphere coincided with areas showing current or previous increases of glucose metabolism on PET in 5 children. NAA/Cr ratios showed no association with clinical seizure frequency.

CONCLUSIONS

Increased glutamate concentrations in the affected hemisphere, measured by MRSI, are common in young children with unilateral SWS and are associated with frequent seizures. The findings lend support to the role of excess glutamate in SWS-associated epilepsy.

Neuroimaging of epilepsy

Imaging is pivotal in the evaluation and management of patients with seizure disorders. Elegant structural neuroimaging with magnetic resonance imaging (MRI) may assist in determining the etiology of focal epilepsy and demonstrating the anatomical changes associated with seizure activity. The high diagnostic yield of MRI to identify the common pathological findings in individuals with focal seizures including mesial temporal sclerosis, vascular anomalies, low-grade glial neoplasms and malformations of cortical development has been demonstrated. Positron emission tomography (PET) is the most commonly performed interictal functional neuroimaging technique that may reveal a focal hypometabolic region concordant with seizure onset. Single photon emission computed tomography (SPECT) studies may assist performance of ictal neuroimaging in patients with pharmacoresistant focal epilepsy being considered for neurosurgical treatment. This chapter highlights neuroimaging developments and innovations, and provides a comprehensive overview of the imaging strategies used to improve the care and management of people with epilepsy.

Mosaic Neurocutaneous Disorders and Their Causes

Neurocutaneous disorders are a heterogeneous group of conditions (mainly) affecting the skin [with pigmentary/vascular abnormalities and/or cutaneous tumours] and the central and peripheral nervous system [with congenital abnormalities and/or tumours]. In a number of such disorders, the skin abnormalities can assume a mosaic patterning (usually arranged in archetypical patterns). Alternating segments of affected and unaffected skin or segmentally arranged patterns of abnormal skin often mirror similar phenomena occurring in extra-cutaneous organs/tissues [eg, eye, bone, heart/vessels, lung, kidney and gut]. In some neurocutaneous syndromes the abnormal mosaic patterning involve mainly the skin and the nervous system configuring a (true) mosaic neurocutaneous disorder; or an ordinary trait of a neurocutaneous disorder is sometimes superimposed by a pronounced linear or otherwise segmental involvement; or, lastly, a neurocutaneous disorder can occur solely in a mosaic pattern. Recently, the molecular genetic and cellular bases of an increasing number of neurocutaneous disorders have been unravelled, shedding light on the interplays between common intra- and extra-neuronal signalling pathways encompassing receptor-protein and protein-to-protein cascades (eg, RAS, MAPK, mTOR, PI3K/AKT and GNAQ pathways), which are often responsible of the mosaic distribution of cutaneous and extra-cutaneous features. In this article we will focus on the well known, and less defined mosaic neurocutaneous phenotypes and their related molecular/genetic bases, including the mosaic neurofibromatoses and their related forms (ie, spinal neurofibromatosis and schwannomatosis); Legius syndrome; segmental arrangements in tuberous sclerosis; Sturge-Weber and Klippel-Trenaunay syndromes; microcephaly/megalencephaly-capillary malformation; blue rubber bleb nevus syndrome; Wyburn-Mason syndrome; mixed vascular nevus syndrome; PHACE syndrome; Incontinentia pigmenti; pigmentary mosaicism of the Ito type; neurocutaneous melanosis; cutis tricolor; speckled lentiginous syndrome; epidermal nevus syndromes; Becker's nevus syndrome; phacomatosis pigmentovascularis and pigmentokeratotica; Proteus syndrome; and encephalocraniocutaneous lipomatosis.