HLA-DQB1*05 subtypes and not DRB1*10:01 mediates risk in anti-IgLON5 disease.

Anti-IgLON5 disease is a rare and likely underdiagnosed subtype of autoimmune encephalitis. The disease displays a heterogeneous phenotype that includes sleep, movement and bulbar-associated dysfunction. The presence of IgLON5-antibodies in CSF/serum, together with a strong association with HLA-DRB1*10:01∼DQB1*05:01, supports an autoimmune basis. In this study, a multicentric human leukocyte antigen (HLA) study of 87 anti-IgLON5 patients revealed a stronger association with HLA-DQ than HLA-DR. Specifically, we identified a predisposing rank-wise association with HLA-DQA1*01:05∼DQB1*05:01, HLA-DQA1*01:01∼DQB1*05:01 and HLA-DQA1*01:04∼DQB1*05:03 in 85% of patients. HLA sequences and binding cores for these three DQ heterodimers were similar, unlike those of linked DRB1 alleles, supporting a causal link to HLA-DQ. This association was further reflected in an increasingly later age of onset across each genotype group, with a delay of up to 11 years, while HLA-DQ-dosage dependent effects were also suggested by reduced risk in the presence of non-predisposing DQ1 alleles. The functional relevance of the observed HLA-DQ molecules was studied with competition binding assays. These proof-of-concept experiments revealed preferential binding of IgLON5 in a post-translationally modified, but not native, state to all three risk-associated HLA-DQ receptors. Further, a deamidated peptide from the Ig2-domain of IgLON5 activated T cells in two patients, compared with one control carrying HLA-DQA1*01:05∼DQB1*05:01. Taken together, these data support a HLA-DQ-mediated T-cell response to IgLON5 as a potentially key step in the initiation of autoimmunity in this disease.

A morphological analysis of calcium hydroxylapatite and poly-l-lactic acid biostimulator particles.

Injectable fillers, pivotal in aesthetic medicine, have evolved significantly with recent trends favoring biostimulators like calcium hydroxylapatite (CaHA-CMC; Radiesse, Merz Aesthetics, Raleigh, NC) and poly-l-lactic acid (PLLA; Sculptra Aesthetics, Galderma, Dallas, TX). This study aims to compare the particle morphology of these two injectables and examine its potential clinical implications. Utilizing advanced light and scanning electron microscopy techniques, the physical characteristics of CaHA-CMC and PLLA particles were analyzed, including shape, size, circularity, roundness, aspect ratio, and quantity of phagocytosable particles. The findings reveal several morphological contrasts: CaHA-CMC particles exhibited a smooth, homogenous, spherical morphology with diameters predominantly ranging between 20 and 45 µm, while PLLA particles varied considerably in shape and size, appearing as micro flakes ranging from 2 to 150 µm in major axis length. The circularity and roundness of CaHA-CMC particles were significantly higher compared to PLLA, indicating a more uniform shape. Aspect ratio analysis further underscored these differences, with CaHA-CMC particles showing a closer resemblance to circles, unlike the more oblong PLLA particles. Quantification of the phagocytosable content of both injectables revealed a higher percentage of phagocytosable particles in PLLA. These morphological distinctions may influence the tissue response to each treatment. CaHA-CMC's uniform, spherical particles may result in reduced inflammatory cell recruitment, whereas PLLA's heterogeneous particle morphology may evoke a more pronounced inflammatory response.

Slowing of Frontal ß Oscillations in Atypical Parkinsonism.

BACKGROUND: Diagnosis of atypical parkinsonian syndromes (APS) mostly relies on clinical presentation as well as structural and molecular brain imaging. Whether parkinsonian syndromes are distinguishable based on neuronal oscillations has not been investigated so far. OBJECTIVE: The aim was to identify spectral properties specific to atypical parkinsonism. METHODS: We measured resting-state magnetoencephalography in 14 patients with corticobasal syndrome (CBS), 16 patients with progressive supranuclear palsy (PSP), 33 patients with idiopathic Parkinson's disease, and 24 healthy controls. We compared spectral power as well as amplitude and frequency of power peaks between groups. RESULTS: Atypical parkinsonism was associated with spectral slowing, distinguishing both CBS and PSP from Parkinson's disease (PD) and age-matched healthy controls. Patients with atypical parkinsonism showed a shift in ß peaks (13-30 Hz) toward lower frequencies in frontal areas bilaterally. A concomitant increase in θ/α power relative to controls was observed in both APS and PD. CONCLUSION: Spectral slowing occurs in atypical parkinsonism, affecting frontal ß oscillations in particular. Spectral slowing with a different topography has previously been observed in other neurodegenerative disorders, such as Alzheimer's disease, suggesting that spectral slowing might be an electrophysiological marker of neurodegeneration. As such, it might support differential diagnosis of parkinsonian syndromes in the future. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Results of a Randomized Clinical Trial of Speech After Early Neurostimulation in Parkinson's Disease.

BACKGROUND: The EARLYSTIM trial demonstrated for Parkinson's disease patients with early motor complications that deep brain stimulation of the subthalamic nucleus (STN-DBS) and best medical treatment (BMT) was superior to BMT alone. OBJECTIVE: This prospective, ancillary study on EARLYSTIM compared changes in blinded speech intelligibility assessment between STN-DBS and BMT over 2 years, and secondary outcomes included non-speech oral movements (maximum phonation time [MPT], oral diadochokinesis), physician- and patient-reported assessments. METHODS: STN-DBS (n = 102) and BMT (n = 99) groups underwent assessments on/off medication at baseline and 24 months (in four conditions: on/off medication, ON/OFF stimulation-for STN-DBS). Words and sentences were randomly presented to blinded listeners, and speech intelligibility rate was measured. Statistical analyses compared changes between the STN-DBS and BMT groups from baseline to 24 months. RESULTS: Over the 2-year period, changes in speech intelligibility and MPT, as well as patient-reported outcomes, were not different between groups, either off or on medication or OFF or ON stimulation, but most outcomes showed a nonsignificant trend toward worsening in both groups. Change in oral diadochokinesis was significantly different between STN-DBS and BMT groups, on medication and OFF STN-DBS, with patients in the STN-DBS group performing slightly worse than patients under BMT only. A signal for clinical worsening with STN-DBS was found for the individual speech item of the Unified Parkinson's Disease Rating Scale, Part III. CONCLUSION: At this early stage of the patients' disease, STN-DBS did not result in a consistent deterioration in blinded speech intelligibility assessment and patient-reported communication, as observed in studies of advanced Parkinson's Disease. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Update on quality assurance in neuropathology: Summary of the round robin trials on TERT promoter mutation, H3-3A mutation, 1p/19q codeletion, and KIAA1549::BRAF fusion testing in Germany in 2020 and 2021.

We previously reported on the first neuropathological round robin trials operated together with Quality in Pathology (QuIP) GmbH in 2018 and 2019 in Germany, i.e., the trials on IDH mutational testing and MGMT promoter methylation analysis [1]. For 2020 and 2021, the spectrum of round robin trials has been expanded to cover the most commonly used assays in neuropathological institutions. In addition to IDH mutation and MGMT promoter methylation testing, there is a long tradition for 1p/19q codeletion testing relevant in the context of the diagnosis of oligodendroglioma. With the 5th edition of the World Health Organization (WHO) classification of the central nervous system tumors, additional molecular markers came into focus: TERT promoter mutation is often assessed as a molecular diagnostic criterion for IDH-wildtype glioblastoma. Moreover, several molecular diagnostic markers have been introduced for pediatric brain tumors. Here, trials on KIAA1549::BRAF fusions (common in pilocytic astrocytomas) and H3-3A mutations (in diffuse midline gliomas, H3-K27-altered and diffuse hemispheric gliomas, H3-G34-mutant) were most desired by the neuropathological community. In this update, we report on these novel round robin trials. In summary, success rates in all four trials ranged from 75 to 96%, arguing for an overall high quality level in the field of molecular neuropathological diagnostics.

Comparison of Physicochemical Characteristics and Biostimulatory Functions in Two Calcium Hydroxyapatite-Based Dermal Fillers.

BACKGROUND:   Dermal fillers containing calcium hydroxyapatite (CaHA) are categorized as biostimulatory. However, differences in CaHA biomaterial likely affect the resultant induction of collagen synthesis, and variability in microsphere shape and size likely influences a patient’s immune response. This study compares 2 CaHA based fillers: one suspended in carboxymethylcellulose (denoted "CaHA/CMC"), and one crosslinked with 1,4-butanediol diglycidyl ether to hyaluronic acid (denoted "CaHA/HA"). OBJECTIVE: To characterize CaHA/CMC and CaHA/HA fillers to stimulate in vitro collagen biosynthesis. METHODS: Physicochemical evaluations included G′ and extrusion force. Scanning electron microscopy (SEM) was used to characterize isolated CaHA microspheres and freeze-dried formulations. Collagen I and III expression were evaluated using immunofluorescence. RESULTS: CaHA/CMC showed higher G′ (P<0.001) and lower extrusion force (P=0.0003), with uniform polymeric-matrix interactions, compared with CaHA/HA. On SEM, isolated microspheres and freeze-dried CaHA/CMC showed round and smooth surfaced microspheres of similar size. Isolated microspheres and freeze-dried CaHA/HA showed nonhomogeneous, broken microspheres, of various sizes, with fragments embedded in the polymer matrix. Although both fillers induced collagen III expression, only CaHA/CMC induced longer-lasting collagen I expression, with increases of 123% (P=0.007) and 164% (P<0.0001) at 2 and 5 mg/mL, respectively, compared with control. CaHA/CMC also increased collagen I expression at equivalent CaHA microsphere concentrations at 2 (P=0.0052) and 5 mg/mL (P<0.0001), compared with CaHA/HA. CONCLUSION: The physicochemical characteristics selected for evaluation were more favorable for CaHA/CMC than CaHA/HA. When compared with CaHA/HA, the smooth, homogeneous microsphere composition of CaHA/CMC promoted significantly more collagen I biosynthesis, an essential process for tissue augmentation and long-lasting aesthetic improvement. Citation: Kunzler C, Hartmann C, Nowag B, et al. Comparison of physicochemical characteristics and biostimulatory functions in two calcium hydroxyapatite-based dermal fillers. J Drugs Dermatol. 2023;22(9):910-916. doi:10.36849/JDD.7684.

Low-grade diffusely infiltrative tumour (LGDIT), SMARCB1-mutant: A clinical and histopathological distinct entity showing epigenetic similarity with ATRT-MYC.

Low-grade diffusely infiltrative tumour (LGDIT), SMARCB1-mutant, is a histopathological distinct low-grade lesion encountered in older children and young adults that shows epigenetic similarity with ATRT-MYC and has the potential for malignant progression.

Anaplastic ganglioglioma-A diagnosis comprising several distinct tumour types.

AIMS: Anaplastic ganglioglioma is a rare tumour, and diagnosis has been based on histological criteria. The 5th edition of the World Health Organization Classification of Tumours of the Central Nervous System (CNS WHO) does not list anaplastic ganglioglioma as a distinct diagnosis due to lack of molecular data in previous publications. We retrospectively compiled a cohort of 54 histologically diagnosed anaplastic gangliogliomas to explore whether the molecular profiles of these tumours represent a separate type or resolve into other entities. METHODS: Samples were subjected to histological review, desoxyribonucleic acid (DNA) methylation profiling and next-generation sequencing. Morphological and molecular data were summarised to an integrated diagnosis. RESULTS: The majority of tumours designated as anaplastic gangliogliomas resolved into other CNS WHO diagnoses, most commonly pleomorphic xanthoastrocytoma (16/54), glioblastoma, isocitrate dehydrogenase protein (IDH) wild type and diffuse paediatric-type high-grade glioma, H3 wild type and IDH wild type (11 and 2/54), followed by low-grade glial or glioneuronal tumours including pilocytic astrocytoma, dysembryoplastic neuroepithelial tumour and diffuse leptomeningeal glioneuronal tumour (5/54), IDH mutant astrocytoma (4/54) and others (6/54). A subset of tumours (10/54) was not assignable to a CNS WHO diagnosis, and common molecular profiles pointing to a separate entity were not evident. CONCLUSIONS: In summary, we show that tumours histologically diagnosed as anaplastic ganglioglioma comprise a wide spectrum of CNS WHO tumour types with different prognostic and therapeutic implications. We therefore suggest assigning this designation with caution and recommend comprehensive molecular workup.

Oligosarcomas, IDH-mutant are distinct and aggressive.

Oligodendrogliomas are defined at the molecular level by the presence of an IDH mutation and codeletion of chromosomal arms 1p and 19q. In the past, case reports and small studies described gliomas with sarcomatous features arising from oligodendrogliomas, so called oligosarcomas. Here, we report a series of 24 IDH-mutant oligosarcomas from 23 patients forming a distinct methylation class. The tumors were recurrences from prior oligodendrogliomas or developed de novo. Precursor tumors of 12 oligosarcomas were histologically and molecularly indistinguishable from conventional oligodendrogliomas. Oligosarcoma tumor cells were embedded in a dense network of reticulin fibers, frequently showing p53 accumulation, positivity for SMA and CALD1, loss of OLIG2 and gain of H3K27 trimethylation (H3K27me3) as compared to primary lesions. In 5 oligosarcomas no 1p/19q codeletion was detectable, although it was present in the primary lesions. Copy number neutral LOH was determined as underlying mechanism. Oligosarcomas harbored an increased chromosomal copy number variation load with frequent CDKN2A/B deletions. Proteomic profiling demonstrated oligosarcomas to be highly distinct from conventional CNS WHO grade 3 oligodendrogliomas with consistent evidence for a smooth muscle differentiation. Expression of several tumor suppressors was reduced with NF1 being lost frequently. In contrast, oncogenic YAP1 was aberrantly overexpressed in oligosarcomas. Panel sequencing revealed mutations in NF1 and TP53 along with IDH1/2 and TERT promoter mutations. Survival of patients was significantly poorer for oligosarcomas as first recurrence than for grade 3 oligodendrogliomas as first recurrence. These results establish oligosarcomas as a distinct group of IDH-mutant gliomas differing from conventional oligodendrogliomas on the histologic, epigenetic, proteomic, molecular and clinical level. The diagnosis can be based on the combined presence of (a) sarcomatous histology, (b) IDH-mutation and (c) TERT promoter mutation and/or 1p/19q codeletion, or, in unresolved cases, on its characteristic DNA methylation profile.

Neurologic manifestations of COVID-19 in critically ill patients: results of the prospective multicenter registry PANDEMIC.

BACKGROUND: Neurologic manifestations are increasingly reported in patients with coronavirus disease 2019 (COVID-19). Yet, data on prevalence, predictors and relevance for outcome of neurological manifestations in patients requiring intensive care are scarce. We aimed to characterize prevalence, risk factors and impact on outcome of neurologic manifestations in critically ill COVID-19 patients. METHODS: In the prospective, multicenter, observational registry study PANDEMIC (Pooled Analysis of Neurologic DisordErs Manifesting in Intensive care of COVID-19), we enrolled COVID-19 patients with neurologic manifestations admitted to 19 German intensive care units (ICU) between April 2020 and September 2021. We performed descriptive and explorative statistical analyses. Multivariable models were used to investigate factors associated with disorder categories and their underlying diagnoses as well as to identify predictors of outcome. RESULTS: Of the 392 patients included in the analysis, 70.7% (277/392) were male and the mean age was 65.3 (SD ± 3.1) years. During the study period, a total of 2681 patients with COVID-19 were treated at the ICUs of 15 participating centers. New neurologic disorders were identified in 350 patients, reported by these centers, suggesting a prevalence of COVID-19-associated neurologic disorders of 12.7% among COVID-19 ICU patients. Encephalopathy (46.2%; 181/392), cerebrovascular (41.0%; 161/392) and neuromuscular disorders (20.4%; 80/392) were the most frequent categories identified. Out of 35 cerebrospinal fluid analyses with reverse transcriptase PCR for SARS-COV-2, only 3 were positive. In-hospital mortality was 36.0% (140/389), and functional outcome (mRS 3 to 5) of surviving patients was poor at hospital discharge in 70.9% (161/227). Intracerebral hemorrhage (OR 6.2, 95% CI 2.5-14.9, p < 0.001) and acute ischemic stroke (OR 3.9, 95% CI 1.9-8.2, p < 0.001) were the strongest predictors of poor outcome among the included patients. CONCLUSIONS: Based on this well-characterized COVID-19 ICU cohort, that comprised 12.7% of all severe ill COVID-19 patients, neurologic manifestations increase mortality and morbidity. Since no reliable evidence of direct viral affection of the nervous system by COVID-19 could be found, these neurologic manifestations may for a great part be indirect para- or postinfectious sequelae of the infection or severe critical illness. Neurologic ICU complications should be actively searched for and treated.

Sustained response to bevacizumab in a patient with mosaic neurofibromatosis type 2 carrying the NF2:c.784C>T p.(Arg262*) variant.

Neurofibromatosis type 2 (NF2) is a tumor predisposition syndrome characterized by the growth of schwannomas, especially bilateral vestibular schwannomas (VS), meningiomas, and ependymomas. The anti-VEGF antibody bevacizumab has shown efficacy for VS in some NF2 patients. However, there is limited data on the effect of bevacizumab on non-vestibular tumors, and on the correlation between therapy response and genotype. Here, we report on a 33-year-old patient with bilateral VS, 14 additional intracranial or spinal schwannomas, and a meningioma treated with bevacizumab, off-label in the European Union, for 2 years. The genotype of the patient was determined by mutational analysis of NF2, SMARCB1, and LZTR1 on DNA of multiple tissues. Additionally, we performed volumetric measurements of quantifiable non-vestibular tumors (n = 8) on MRI scans from 5 pre-therapeutic and 2 therapeutic years, and pure-tone audiometry of the non-deaf ear. A heterozygous NM_000268.3(NF2):c.784C>T p.(Arg262*) variant was identified in DNA from 3 schwannomas, but not in leukocyte or oral mucosa DNA, and no rare SMARCB1/LZTR1 variants were detected, establishing the diagnosis of definite NF2 mosaicism. While schwannomas had progressed with a mean annual growth rate of 38% pre-therapeutically, volume stabilization or reduction of all schwannomas along with improvement of pain and neurological deficits, including hearing impairment, were observed under 24 months of bevacizumab. In summary, this is the first report of a sustained response to bevacizumab in a patient shown to carry the frequent mosaic NF2:c.784C>T p.(Arg262*) variant. Our results may be of particular relevance to guide treatment decisions in mosaic NF2 patients harboring this variant.

Multicenter Validation of Individual Preoperative Motor Outcome Prediction for Deep Brain Stimulation in Parkinson's Disease.

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN DBS) is an established therapy for Parkinson's disease (PD) patients suffering from motor response fluctuations despite optimal medical treatment, or severe dopaminergic side effects. Despite careful clinical selection and surgical procedures, some patients do not benefit from STN DBS. Preoperative prediction models are suggested to better predict individual motor response after STN DBS. We validate a preregistered model, DBS-PREDICT, in an external multicenter validation cohort. METHODS: DBS-PREDICT considered eleven, solely preoperative, clinical characteristics and applied a logistic regression to differentiate between weak and strong motor responders. Weak motor response was defined as no clinically relevant improvement on the Unified Parkinson's Disease Rating Scale (UPDRS) II, III, or IV, 1 year after surgery, defined as, respectively, 3, 5, and 3 points or more. Lower UPDRS III and IV scores and higher age at disease onset contributed most to weak response predictions. Individual predictions were compared with actual clinical outcomes. RESULTS: 322 PD patients treated with STN DBS from 6 different centers were included. DBS-PREDICT differentiated between weak and strong motor responders with an area under the receiver operator curve of 0.76 and an accuracy up to 77%. CONCLUSION: Proving generalizability and feasibility of preoperative STN DBS outcome prediction in an external multicenter cohort is an important step in creating clinical impact in DBS with data-driven tools. Future prospective studies are required to overcome several inherent practical and statistical limitations of including clinical decision support systems in DBS care.

IgG4-related hypertrophic pachymeningitis with tumor-like intracranial and intracerebral lesions.

OBJECTIVE: IgG4-related hypertrophic pachymeningitis is a rare fibroinflammatory disorder that may cause localized or diffused thickening of the dura mater. Misinterpretations of the clinical and imaging findings are common. Clinical manifestations depend on the location of the inflammatory lesion and on compression of neural structures leading to functional deficits. A dural biopsy is commonly needed for a definitive diagnosis. Immunomodulatory therapy is considered the therapy of choice. METHODS: Four patients with IgG4-related hypertrophic pachymeningitis were identified over a 5-year period. Patient-related characteristics including age, preoperative workup, signs and symptoms of patients, and diagnostic procedures were evaluated. Furthermore, the surgical treatment and 5-year follow-up outcomes were analyzed. RESULTS: There were two adults and two adolescents (mean age 32 years; range 15 to 67 years). Two patients were male, and two were female. No history of disease was known in any of the patients. Clinical symptoms were epilepsy (n = 2), ataxia and nausea (n = 1), and facial nerve palsy (n = 1). MR imaging studies showed contrast enhancing lesions in the temporal region in two patients, and in the cerebellar region in the other two patients. Subtotal resection was performed in two instances and a biopsy via a suboccipital retrosigmoid approach was obtained in the other two patients. Histochemical and immunohistochemical investigations revealed an IgG 4 disease in all of these patients. Immunomodulatorry therapy led to clinical stability during follow-up of 5 years in all four cases. CONCLUSION: The diagnosis of IgG4-related hypertrophic pachymeningitis is challenging, but is of great relevance as treatment differs significantly from other forms of pachymeningitis and a specific therapeutic approach may avoid long-term neurological complications. Our series contributes to a better clinical characterization of this rare disease.

Motor Evoked Potentials Improve Targeting in Deep Brain Stimulation Surgery.

OBJECTIVES: One of the main challenges posed by the surgical deep brain stimulation (DBS) procedure is the successful targeting of the structures of interest and avoidance of side effects, especially in asleep surgery. Here, intraoperative motor evoked potentials (MEPs) might serve as tool to identify the pyramidal tract. We hypothesized that intraoperative MEPs are useful to define the distance to the pyramidal tract and reduce the occurrence of postoperative capsular side effects. MATERIALS AND METHODS: Motor potentials were evoked through both microelectrode and DBS-electrode stimulation during stereotactic DBS surgery on 25 subthalamic nuclei and 3 ventral intermediate thalamic nuclei. Internal capsule proximity was calculated for contacts on microelectrode trajectories, as well as for DBS-electrodes, and correlated with the corresponding MEP thresholds. Moreover, the predictivity of intraoperative MEP thresholds on the probability of postoperative capsular side effects was calculated. RESULTS: Intraoperative MEPs thresholds correlated significantly with internal capsule proximity, regardless of the stimulation source. Furthermore, MEPs thresholds were highly accurate to exclude the occurrence of postoperative capsular side effects. CONCLUSIONS: Intraoperative MEPs provide additional targeting guidance, especially in asleep DBS surgery, where clinical value of microelectrode recordings and test stimulation may be limited. As this technique can exclude future capsular side effects, it can directly be translated into clinical practice.

Directional Deep Brain Stimulation for Parkinson's Disease: Results of an International Crossover Study With Randomized, Double-Blind Primary Endpoint.

OBJECTIVE: Published reports on directional deep brain stimulation (DBS) have been limited to small, single-center investigations. Therapeutic window (TW) is used to describe the range of stimulation amplitudes achieving symptom relief without side effects. This crossover study performed a randomized double-blind assessment of TW for directional and omnidirectional DBS in a large cohort of patients implanted with a DBS system in the subthalamic nucleus for Parkinson's disease. MATERIALS AND METHODS: Participants received omnidirectional stimulation for the first three months after initial study programming, followed by directional DBS for the following three months. The primary endpoint was a double-blind, randomized evaluation of TW for directional vs omnidirectional stimulation at three months after initial study programming. Additional data recorded at three- and six-month follow-ups included stimulation preference, therapeutic current strength, Unified Parkinson's Disease Rating Scale (UPDRS) part III motor score, and quality of life. RESULTS: The study enrolled 234 subjects (62 ± 8 years, 33% female). TW was wider using directional stimulation in 183 of 202 subjects (90.6%). The mean increase in TW with directional stimulation was 41% (2.98 ± 1.38 mA, compared to 2.11 ± 1.33 mA for omnidirectional). UPDRS part III motor score on medication improved 42.4% at three months (after three months of omnidirectional stimulation) and 43.3% at six months (after three months of directional stimulation) with stimulation on, compared to stimulation off. After six months, 52.8% of subjects blinded to stimulation type (102/193) preferred the period with directional stimulation, and 25.9% (50/193) preferred the omnidirectional period. The directional period was preferred by 58.5% of clinicians (113/193) vs 21.2% (41/193) who preferred the omnidirectional period. CONCLUSION: Directional stimulation yielded a wider TW compared to omnidirectional stimulation and was preferred by blinded subjects and clinicians.

The prognostic significance of clinicopathological features in meningiomas: Microscopic brain invasion can predict patient outcome in otherwise benign meningiomas.

AIMS: Brain invasion (BI) was firstly defined as a single criterion of atypia in otherwise benign meningiomas in the revised fourth edition of 2016 WHO classification of brain tumours after being previously inconsistently addressed. However, recent studies have raised doubts about the prognostic significance of BI in otherwise benign meningiomas. In our study, we investigate the reproducibility of such a prognostic effect. METHODS: We identified two cohorts one consisting of 483 patients with meningioma WHO grade I (M°I) or atypical meningioma WHO grade II (M°II) from Hannover Medical School and the other including atypical meningiomas defined according to the classical WHO criteria (M°IIb) from the University Hospital Heidelberg. Follow-up data with a median observation time of 38.2 months were available from 308 cases. These included 243 M°I and 65 M°II patients with the latter group consisting of 25 patients with otherwise benign meningiomas with BI (M°IIa) and 40 with M°IIb. RESULTS: A significant difference of progression-free interval (PFI) was found between patients with M°I and M°II, M°I and M°IIa and those with M°I and M°IIb of both cohorts and each separately. However, PFI of M°IIa and M°IIb patients showed no significant difference. In the multivariate regression analysis adjusted for M°I/M°IIa versus M°IIb, sex, age, extent of resection and tumour location, BI exhibited the strongest risk of relapse (Hazard ratio: 4.95) serving as an independent predictor of PFI (p = 0.002). CONCLUSIONS: Our results clearly support the definition of BI as a single criterion of atypia in WHO classification of 2016.

Molecular characterisation of sporadic endolymphatic sac tumours and comparison to von Hippel-Lindau disease-related tumours.

AIMS: Although inactivation of the von Hippel-Lindau gene (VHL) on chromosome 3p25 is considered to be the major cause of hereditary endolymphatic sac tumours (ELSTs), the genetic background of sporadic ELST is largely unknown. The aim of this study was to determine the prevalence of VHL mutations in sporadic ELSTs and compare their characteristics to VHL-disease-related tumours. METHODS: Genetic and epigenetic alterations were compared between 11 sporadic and 11 VHL-disease-related ELSTs by targeted sequencing and DNA methylation analysis. RESULTS: VHL mutations and small deletions detected by targeted deep sequencing were identified in 9/11 sporadic ELSTs (82%). No other cancer-related genetic pathway was altered except for TERT promoter mutations in two sporadic ELST and one VHL-disease-related ELST (15%). Loss of heterozygosity of chromosome 3 was found in 6/10 (60%) VHL-disease-related and 10/11 (91%) sporadic ELSTs resulting in biallelic VHL inactivation in 8/10 (73%) sporadic ELSTs. DNA methylation profiling did not reveal differences between sporadic and VHL-disease-related ELSTs but reliably distinguished ELST from morphological mimics of the cerebellopontine angle. VHL patients were significantly younger at disease onset compared to sporadic ELSTs (29 vs. 52 years, p < 0.0001, Fisher's exact test). VHL-disease status was not associated with an increased risk of recurrence, but the presence of clear cells was found to be associated with shorter progression-free survival (p = 0.0002, log-rank test). CONCLUSION: Biallelic inactivation of VHL is the main mechanism underlying ELSTs, but unknown mechanisms beyond VHL may rarely be involved in the pathogenesis of sporadic ELSTs.

Rare germline variants in the E-cadherin gene CDH1 are associated with the risk of brain tumors of neuroepithelial and epithelial origin.

The genetic basis of brain tumor development is poorly understood. Here, leukocyte DNA of 21 patients from 15 families with ≥ 2 glioma cases each was analyzed by whole-genome or targeted sequencing. As a result, we identified two families with rare germline variants, p.(A592T) or p.(A817V), in the E-cadherin gene CDH1 that co-segregate with the tumor phenotype, consisting primarily of oligodendrogliomas, WHO grade II/III, IDH-mutant, 1p/19q-codeleted (ODs). Rare CDH1 variants, previously shown to predispose to gastric and breast cancer, were significantly overrepresented in these glioma families (13.3%) versus controls (1.7%). In 68 individuals from 28 gastric cancer families with pathogenic CDH1 germline variants, brain tumors, including a pituitary adenoma, were observed in three cases (4.4%), a significantly higher prevalence than in the general population (0.2%). Furthermore, rare CDH1 variants were identified in tumor DNA of 6/99 (6%) ODs. CDH1 expression was detected in undifferentiated and differentiating oligodendroglial cells isolated from rat brain. Functional studies using CRISPR/Cas9-mediated knock-in or stably transfected cell models demonstrated that the identified CDH1 germline variants affect cell membrane expression, cell migration and aggregation. E-cadherin ectodomain containing variant p.(A592T) had an increased intramolecular flexibility in a molecular dynamics simulation model. E-cadherin harboring intracellular variant p.(A817V) showed reduced ß-catenin binding resulting in increased cytosolic and nuclear ß-catenin levels reverted by treatment with the MAPK interacting serine/threonine kinase 1 inhibitor CGP 57380. Our data provide evidence for a role of deactivating CDH1 variants in the risk and tumorigenesis of neuroepithelial and epithelial brain tumors, particularly ODs, possibly via WNT/ß-catenin signaling.

Clear cell meningiomas are defined by a highly distinct DNA methylation profile and mutations in SMARCE1.

Clear cell meningioma represents an uncommon variant of meningioma that typically affects children and young adults. Although an enrichment of loss-of-function mutations in the SMARCE1 gene has been reported for this subtype, comprehensive molecular investigations are lacking. Here we describe a molecularly distinct subset of tumors (n = 31), initially identified through genome-wide DNA methylation screening among a cohort of 3093 meningiomas, of which most were diagnosed histologically as clear cell meningioma. This cohort was further supplemented by an additional 11 histologically diagnosed clear cell meningiomas for analysis (n = 42). Targeted DNA sequencing revealed SMARCE1 mutations in 33/34 analyzed samples, accompanied by a nuclear loss of expression determined via immunohistochemistry and a decreased SMARCE1 transcript expression in the tumor cells. Analysis of time to progression or recurrence of patients within the clear cell meningioma group (n = 14) in comparison to those with meningioma WHO grade 2 (n = 220) revealed a similar outcome and support the assignment of WHO grade 2 to these tumors. Our findings indicate the existence of a highly distinct epigenetic signature of clear cell meningiomas, separate from all other variants of meningiomas, with recurrent mutations in the SMARCE1 gene. This suggests that these tumors may arise from a different precursor cell population than the broad spectrum of the other meningioma subtypes.

Primary mismatch repair deficient IDH-mutant astrocytoma (PMMRDIA) is a distinct type with a poor prognosis.

Diffuse IDH-mutant astrocytoma mostly occurs in adults and carries a favorable prognosis compared to IDH-wildtype malignant gliomas. Acquired mismatch repair deficiency is known to occur in recurrent IDH-mutant gliomas as resistance mechanism towards alkylating chemotherapy. In this multi-institutional study, we report a novel epigenetic group of 32 IDH-mutant gliomas with proven or suspected hereditary mismatch repair deficiency. None of the tumors exhibited a combined 1p/19q deletion. These primary mismatch repair-deficient IDH-mutant astrocytomas (PMMRDIA) were histologically high-grade and were mainly found in children, adolescents and young adults (median age 14 years). Mismatch repair deficiency syndromes (Lynch or Constitutional Mismatch Repair Deficiency Syndrom (CMMRD)) were clinically diagnosed and/or germline mutations in DNA mismatch repair genes (MLH1, MSH6, MSH2) were found in all cases, except one case with a family and personal history of colon cancer and another case with MSH6-deficiency available only as recurrent tumor. Loss of at least one of the mismatch repair proteins was detected via immunohistochemistry in all, but one case analyzed. Tumors displayed a hypermutant genotype and microsatellite instability was present in more than half of the sequenced cases. Integrated somatic mutational and chromosomal copy number analyses showed frequent inactivation of TP53, RB1 and activation of RTK/PI3K/AKT pathways. In contrast to the majority of IDH-mutant gliomas, more than 60% of the samples in our cohort presented with an unmethylated MGMT promoter. While the rate of immuno-histochemical ATRX loss was reduced, variants of unknown significance were more frequently detected possibly indicating a higher frequency of ATRX inactivation by protein malfunction. Compared to reference cohorts of other IDH-mutant gliomas, primary mismatch repair-deficient IDH-mutant astrocytomas have by far the worst clinical outcome with a median survival of only 15 months irrespective of histological or molecular features. The findings reveal a so far unknown entity of IDH-mutant astrocytoma with high prognostic relevance. Diagnosis can be established by aligning with the characteristic DNA methylation profile, by DNA-sequencing-based proof of mismatch repair deficiency or immunohistochemically demonstrating loss-of-mismatch repair proteins.