Diffuse glioneuronal tumour with oligodendroglioma-like features and nuclear clusters (DGONC) - a molecularly defined glioneuronal CNS tumour class displaying recurrent monosomy 14.

AIMS: DNA methylation-based central nervous system (CNS) tumour classification has identified numerous molecularly distinct tumour types, and clinically relevant subgroups among known CNS tumour entities that were previously thought to represent homogeneous diseases. Our study aimed at characterizing a novel, molecularly defined variant of glioneuronal CNS tumour. PATIENTS AND METHODS: DNA methylation profiling was performed using the Infinium MethylationEPIC or 450 k BeadChip arrays (Illumina) and analysed using the 'conumee' package in R computing environment. Additional gene panel sequencing was also performed. Tumour samples were collected at the German Cancer Research Centre (DKFZ) and provided by multinational collaborators. Histological sections were also collected and independently reviewed. RESULTS: Genome-wide DNA methylation data from >25 000 CNS tumours were screened for clusters separated from established DNA methylation classes, revealing a novel group comprising 31 tumours, mainly found in paediatric patients. This DNA methylation-defined variant of low-grade CNS tumours with glioneuronal differentiation displays recurrent monosomy 14, nuclear clusters within a morphology that is otherwise reminiscent of oligodendroglioma and other established entities with clear cell histology, and a lack of genetic alterations commonly observed in other (paediatric) glioneuronal entities. CONCLUSIONS: DNA methylation-based tumour classification is an objective method of assessing tumour origins, which may aid in diagnosis, especially for atypical cases. With increasing sample size, methylation analysis allows for the identification of rare, putative new tumour entities, which are currently not recognized by the WHO classification. Our study revealed the existence of a DNA methylation-defined class of low-grade glioneuronal tumours with recurrent monosomy 14, oligodendroglioma-like features and nuclear clusters.

Clinical, radiological, histological and molecular characteristics of paediatric epithelioid glioblastoma.

AIMS: A few case series in adults have described the characteristics of epithelioid glioblastoma (e-GB), one of the rarest variants of this cancer. We evaluated clinical, radiological, histological and molecular characteristics in the largest series to date of paediatric e-GB. METHODS: Review of clinical characteristics and therapy, imaging studies and histology was performed in patients younger than 22 years with e-GB seen at our institution over 15 years. Sequencing of hotspot mutations and fluorescence in situ hybridization of relevant genes were undertaken. RESULTS: Median age at diagnosis of six patients was 7.6 years. Tumours originated in the cerebral cortex (n = 2) or diencephalon (n = 4). Three patients presented with acute, massive haemorrhage and three had leptomeningeal dissemination at diagnosis. Paediatric e-GB had the typical histological characteristics seen in adult tumours. Universal immunoreactivity for INI1 and lack of diverse protein expression were seen in all cases. One tumour had a chromosome 22q loss. Three tumours (50%) harboured a BRAF: p.V600E. One thalamic tumour had an H3F3A p.K27M. All patients received radiation therapy with (n = 3) or without chemotherapy (n = 3). All patients experienced tumour progression with a median survival of 169 days. One patient with nonmetastatic disease had early leptomeningeal progression. Two patients had symptomatic tumour spread outside the central nervous system (CNS) through a ventriculoperitoneal shunt. One additional patient had widespread metastases outside the CNS identified at autopsy. CONCLUSIONS: Paediatric e-GBs are rare cancers with an aggressive behaviour that share histological and genetic characteristics with their adult counterparts. BRAF inhibition is a potential treatment for these tumours.

Anatomic Neuroimaging Characteristics of Posterior Fossa Type A Ependymoma Subgroups.

BACKGROUND AND PURPOSE: Posterior fossa type A (PFA) ependymomas have 2 molecular subgroups (PFA-1 and PFA-2) and 9 subtypes. Gene expression profiling suggests that PFA-1 and PFA-2 tumors have distinct developmental origins at different rostrocaudal levels of the brainstem. We, therefore, tested the hypothesis that PFA-1 and PFA-2 ependymomas have different anatomic MR imaging characteristics at presentation. MATERIALS AND METHODS: Two neuroradiologists reviewed the preoperative MR imaging examinations of 122 patients with PFA ependymomas and identified several anatomic characteristics, including extension through the fourth ventricular foramina and encasement of major arteries and tumor type (midfloor, roof, or lateral). Deoxyribonucleic acid methylation profiling assigned ependymomas to PFA-1 or PFA-2. Information on PFA subtype from an earlier study was also available for a subset of tumors. Associations between imaging variables and subgroup or subtype were evaluated. RESULTS: No anatomic imaging variable was significantly associated with the PFA subgroup, but 5 PFA-2c subtype ependymomas in the cohort had a more circumscribed appearance and showed less tendency to extend through the fourth ventricular foramina or encase blood vessels, compared with other PFA subtypes. CONCLUSIONS: PFA-1 and PFA-2 ependymomas did not have different anatomic MR imaging characteristics, and these results do not support the hypothesis that they have distinct anatomic origins. PFA-2c ependymomas appear to have a more anatomically circumscribed MR imaging appearance than the other PFA subtypes; however, this needs to be confirmed in a larger study.

Relative ADC and Location Differ between Posterior Fossa Pilocytic Astrocytomas with and without Gangliocytic Differentiation.

BACKGROUND AND PURPOSE: Pilocytic astrocytomas, the most common posterior fossa tumors in children, are characterized by KIAA1549-BRAF fusions and shows excellent 5-year survival rates. Pilocytic astrocytoma with gangliocytic differentiation, a recently defined pilocytic astrocytoma variant that includes glial and neuronal elements similar to a ganglioglioma, may be distinguished from a classic ganglioglioma by molecular, radiologic, and histopathologic features. This study investigated whether imaging could distinguish posterior fossa pilocytic astrocytoma with and without gangliocytic differentiation. MATERIALS AND METHODS: Preoperative MRIs (± CTs) of 41 children (age range, 7 months to 15 years; mean age, 7.3 ± 3.7 years; 58.5% male) with pilocytic astrocytoma with gangliocytic differentiation (n = 7) or pilocytic astrocytoma (n = 34) were evaluated; differences in tumor location, morphology, and minimum relative ADC between tumor types were compared (Wilcoxon rank sum test, Fisher exact test). Histopathology and BRAF fusion/mutation status were reviewed. Associations of progression-free survival with diagnosis, imaging features, and BRAF status were examined by Cox proportional hazards models. RESULTS: Pilocytic astrocytoma with gangliocytic differentiation appeared similar to pilocytic astrocytoma but had lower minimum relative ADC (mean, 1.01 ± 0.17 compared with 2.01 ± 0.38 for pilocytic astrocytoma; P = .0005) and was more commonly located within midline structures (P = .0034). BRAF status was similar for both groups. Non-total resection (hazard ratio, 52.64; P = .0002), pilocytic astrocytoma with gangliocytic differentiation diagnosis (hazard ratio, 4.66; P = .0104), and midline involvement (hazard ratio, 3.32; P = .0433) were associated with shorter progression-free survival. CONCLUSIONS: Minimum relative ADC and tumor location may be useful adjuncts to histopathology in differentiating pilocytic astrocytoma with gangliocytic differentiation from pilocytic astrocytoma. Shorter progression-free survival in pilocytic astrocytoma with gangliocytic differentiation is likely due to a propensity for involvement of midline structures and poor resectability.

Complete Genome Sequences of Zika Virus Strains Isolated from the Blood of Patients in Thailand in 2014 and the Philippines in 2012.

Here, we present the complete genome sequences of two Zika virus (ZIKV) strains, Zika virus/Homo sapiens-tc/THA/2014/SV0127-14 and Zika virus/H. sapiens-tc/PHL/2012/CPC-0740, isolated from the blood of patients collected in Thailand, 2014, and the Philippines, 2012, respectively. Sequencing and phylogenetic analysis showed that both strains belong to the Asian lineage.

MR Imaging Characteristics of Wingless-Type-Subgroup Pediatric Medulloblastoma.

BACKGROUND AND PURPOSE: "Transcriptionally different" medulloblastoma groups are associated with specific signaling pathway abnormalities; hence, they may present with distinct imaging manifestations. In this study, we sought to describe the MR imaging features of wingless-type-subgroup medulloblastomas with embryologic correlations. MATERIALS AND METHODS: Pre- and postoperative imaging studies of 16 patients with wingless-type-subgroup medulloblastoma were evaluated for tumor location, involvement of surrounding CSF spaces or parenchymal structures, conventional and DWI signal properties, and postsurgical damage patterns. Laterality scores were assigned to tumors at each step in the evaluation process. Continuous variables were summarized by using descriptive statistics. The Wilcoxon signed rank test was performed to compare laterality scores. To determine the interobserver variability, we computed the intraclass correlation and Cohen κ coefficients. RESULTS: Wingless-type-subgroup medulloblastomas in our series were histopathologically "classic." Wingless-type-subgroup medulloblastomas occur in specific sites, with involvement of the foramen of Luschka (75%), the fourth ventricle (68.75%), the cisterna magna (31.25%), and the cerebellopontine angle cistern (18.75%). Laterality scores were low (<2) when preoperative primary and secondary anatomic features were evaluated separately, but they increased (>2) when all pre- and postoperative anatomic features were considered. Results were statistically shown to be reproducible (interclass correlation coefficient, 0.71-0.94; Cohen κ, 0.63-1.00). On the basis of anatomic lesion patterns, 4 location-based subtypes may be distinguished: 1) midline-intraventricular, 2) midline-extraventricular, 3) off-midline-intraventricular, and 4) off-midline-extraventricular, which represent a continuum. CONCLUSIONS: Wingless-type-subgroup medulloblastomas are lateralized tumors arising from the brain stem and cerebellum around the foramen of Luschka. Our current understanding of their embryologic origins is in concordance with the spatial distribution of these tumors.

Cross-species epigenetics identifies a critical role for VAV1 in SHH subgroup medulloblastoma maintenance.

The identification of key tumorigenic events in Sonic Hedgehog (SHH) subgroup medulloblastomas (MBSHH) will be essential for the development of individualized therapies and improved outcomes. However, beyond confirmation of characteristic SHH pathway mutations, recent genome-wide sequencing studies have not revealed commonly mutated genes with widespread relevance as potential therapeutic targets. We therefore examined any role for epigenetic DNA methylation events in MBSHH using a cross-species approach to candidate identification, prioritization and validation. MBSHH-associated DNA methylation events were first identified in 216 subgrouped human medulloblastomas (50 MBSHH, 28 Wnt/Wingless, 44 Group 3 and 94 Group 4) and their conservation then assessed in tumors arising from four independent murine models of Shh medulloblastoma, alongside any role in tumorigenesis using functional assessments in mouse and human models. This strategy identified widespread regional CpG hypo-methylation of VAV1, leading to its elevated expression, as a conserved aberrant epigenetic event, which characterizes the majority of MBSHH tumors in both species, and is associated with a poor outcome in MBSHH patients. Moreover, direct modulation of VAV1 in mouse and human models revealed a critical role in tumor maintenance, and its abrogation markedly reduced medulloblastoma growth. Further, Vav1 activity regulated granule neuron precursor germinal zone exit and migration initiation in an ex vivo model of early postnatal cerebellar development. These findings establish VAV1 as a critical epigenetically regulated oncogene with a key role in MBSHH maintenance, and highlight its potential as a validated therapeutic target and prognostic biomarker for the improved therapy of medulloblastoma.

Orthotopic models of pediatric brain tumors in zebrafish.

High-throughput screens (HTS) of compound toxicity against cancer cells can identify thousands of potential new drug-leads. But only limited numbers of these compounds can progress to expensive and labor-intensive efficacy studies in mice, creating a 'bottle neck' in the drug development pipeline. Approaches that triage drug-leads for further study are greatly needed. Here we provide an intermediary platform between HTS and mice by adapting mouse models of pediatric brain tumors to grow as orthotopic xenografts in the brains of zebrafish. Freshly isolated mouse ependymoma, glioma and choroid plexus carcinoma cells expressing red fluorescence protein were conditioned to grow at 34 °C. Conditioned tumor cells were then transplanted orthotopically into the brains of zebrafish acclimatized to ambient temperatures of 34 °C. Live in vivo fluorescence imaging identified robust, quantifiable and reproducible brain tumor growth as well as spinal metastasis in zebrafish. All tumor xenografts in zebrafish retained the histological characteristics of the corresponding parent mouse tumor and efficiently recruited fish endothelial cells to form a tumor vasculature. Finally, by treating zebrafish harboring ERBB2-driven gliomas with an appropriate cytotoxic chemotherapy (5-fluorouracil) or tyrosine kinase inhibitor (erlotinib), we show that these models can effectively assess drug efficacy. Our data demonstrate, for the first time, that mouse brain tumors can grow orthotopically in fish and serve as a platform to study drug efficacy. As large cohorts of brain tumor-bearing zebrafish can be generated rapidly and inexpensively, these models may serve as a powerful tool to triage drug-leads from HTS for formal efficacy testing in mice.

Case of the month: June 1998--2 year old boy with lumbosacral mass.

We report the case of a boy aged 2 years with spina bifida and a lipomyelomeningocele which contained ectopic immature renal tissue. He presented with a swelling over the lumbosacral region, incontinence, and bilateral leg weakness. Histopathologic examination revealed adipose tissue in which a focus of fibrous tissue contained neuroglial elements, striated muscle fibres and clusters of glomeruloid structures surrounded by immature tubules. The differential diagnosis of teratoma and lipomyelomeningocele with nephrogenic rests is discussed with reference to possible pathogenesis.

Subset of neurons characterized by the presence of NADPH-diaphorase in human substantia innominata.

The substantia innominata encompasses an area of the basal forebrain that is ventral to the lenticular nucleus and anterior commissure, medial to the claustrum and external capsule, and lateral to the hypothalamus. The nucleus basalis of Meynert consists primarily of large acetylcholinesterase (AchE)-positive neurons embedded within the substantia innominata. Damage to these neurons may be important in the pathogenesis of cortical dysfunction in Alzheimer's disease. In order to characterize other neuronal elements in the substantia innominata and their relationship to the nucleus basalis, we chose to study a biochemically distinct neuronal subset containing the enzyme nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d). The substantia innominata was blocked from six normal brains obtained postmortem and fixed in neutral-buffered formalin at 4 degrees C for 48 hours. Free-floating 50-micron sections from several levels were stained for NADPH-d or AchE activities. Selected sections were double stained for NADPH-d and AchE. NADPH-d activity was present in a network of pleomorphic neurons that extended through all levels of the substantia innominata and into the striatum and amygdala. NADPH-d neurons were particularly numerous at the level of the anterior commisure and were closely associated with the cholinergic neurons of the nucleus basalis. They were not seen in the ventral pallidum, or the vertical limb of the diagonal band of Broca or in the islands of Calleja. The cell bodies of NADPH-d neurons were quite varied in shape, ranging from ovoid to fusiform, and about half the cells were bipolar. Where neuronal density was high, their dendrites formed an interlacing pattern. NADPH-d-positive fibres were seen coursing through the external capsule, hypothalamus, and amygdala. This novel set of neurons in the substantia innominata may be part of a more extensive network that interacts with the magnocellular basal forebrain system at the level of the nucleus basalis. Whether other neurotransmitters are present within these neurons and whether NADPH-d neurons are involved in Alzheimer's disease remain to be elucidated.

A mitochondrial DNA tRNA(Val) point mutation associated with adult-onset Leigh syndrome.

Subacute necrotizing encephalomyelopathy (Leigh syndrome) is associated with a number of mitochondrial DNA (mtDNA) abnormalities. We studied a family with maternally inherited encephalomyelopathy. Two siblings developed adult-onset Leigh syndrome. Muscle biopsy specimens showed enhanced succinic dehydrogenase activity and cytochrome oxidase-negative fibers. We sequenced the ATPase- and transfer RNA (tRNA)-encoding genes of mtDNA and identified a novel mtDNA valine tRNA mutation at base pair 1644. This transversion was heteroplasmic in blood and muscle in all individuals studied, and the proportion of mutant mtDNA correlated with disease severity. This is the first heteroplasmic transversion within a mtDNA tRNA gene and the second pathogenic mtDNA tRNA(Val) mutation to be associated with human disease.

Cortical myoclonus and cerebellar pathology.

OBJECTIVE: To study the electrophysiologic and pathologic findings in three patients with cortical myoclonus. In two patients the myoclonic ataxic syndrome was associated with proven celiac disease. BACKGROUND: The pathologic findings in conditions associated with cortical myoclonus commonly involve the cerebellar system, but there has only been one report of cerebellar pathology in a patient in whom cortical myoclonus was physiologically characterized antemortem. METHODS: Cortical somatosensory evoked potentials (SEPs) were recorded and EEG activity was averaged preceding myoclonic electromyographic activity. In one patient cortico-cortical inhibition was tested using two paired ipsilateral magnetic stimuli over the motor strip. Neuropathologic examination was carried out, including linear Purkinje cell densities/millimeter calculations for different regions of the cerebellum. RESULTS: The electrophysiology showed evidence of dysfunction of the sensorimotor cortex with enlarged SEPs and a time-locked cortical potential preceding the action myoclonus. In addition, motor cortical inhibition was abnormal in one case. Pathology showed unremarkable primary sensory, motor, and premotor cerebral cortices, except for unilateral gliosis of the motor cortex in one case. The cerebellum showed patchy atrophy and ongoing degeneration. A striking feature was the greater severity of Purkinje cell loss and Bergmann gliosis in the outer aspects than in the depths of the folia. CONCLUSIONS: Pathologic abnormalities are paradoxically mainly located in the cerebellum in some patients with cortical myoclonus, despite clear electrophysiologic evidence of cortical dysfunction. This observation suggests that enhanced excitability of the sensorimotor cortex may arise as a distant effect of cerebellar pathology.

A clinical and genetic study of a manifesting heterozygote with X-linked myotubular myopathy.

X-linked myotubular myopathy (XLMTM) characteristically causes severe or fatal muscle weakness in male infants. Mutations in the gene MTM1, encoding the protein myotubularin, can be identified in most families. Prior to this report, XLMTM was thought not to cause symptomatic manifestations in female carriers. We describe an adult female from a large family with typical XLMTM. The patient had progressive disabling muscle weakness of later onset and lesser severity than that observed in affected males. The distribution of weakness resembled typical XLMTM with facial weakness, marked limb-girdle weakness, respiratory muscle involvement and dysphagia. Analysis of the MTM1 gene identified a heterozygous missense mutation (G378R) within the highly conserved tyrosine phosphatase site of myotubularin. We did not identify significantly skewed X-inactivation. We conclude that XLMTM is capable of causing significant disability in heterozygotes.

Neurochemical characteristics of aluminum-induced neurofibrillary degeneration in rabbits.

Aluminum-induced neurofibrillary degeneration in rabbits is known to affect particular populations of neurons. The neurotransmitter alterations which accompany aluminum neurofibrillary degeneration were examined in order to assess how closely they mimic those of Alzheimer's disease. There was a significant reduction in choline acetyltransferase activity in entorhinal cortex and hippocampus as well as significant reductions in cortical concentrations of serotonin and norepinephrine in the aluminum-treated rabbits. Significant reductions in glutamate, aspartate and taurine were found in frontoparietal and posterior parietal cortex. Concentrations of GABA were unchanged in cerebral cortex. Both substance P and cholecystokinin immunoreactivity were significantly reduced in entorhinal cortex but there were no significant changes in somatostatin, neuropeptide Y and vasoactive intestinal polypeptide. The five neuropeptides were unaffected in striatum, thalamus, cerebellum and brainstem. Neurochemical changes were found in the regions with the most neurofibrillary degeneration while regions with little or no neurofibrillary degeneration were unaffected. The reductions in choline acetyltransferase activity, serotinin and noradrenaline suggest that some neuronal populations preferentially affected in Alzheimer's disease are also affected by aluminum-induced neurofibrillary degeneration; however, the cortical somatostatin deficit which is a feature of Alzheimer's disease is not replicated in the aluminum model.

AIDS presenting as focal segmental membranous glomerulopathy.

The case of a young, heterosexual man who was investigated for proteinuria is reported. A renal biopsy specimen showed a focal and segmental membranous glomerulopathy. He was later found to be HIV positive and died from cerebral infarction associated with HIV vasculitis 16 months after his initial presentation. Unusual forms of immune complex mediated glomerulopathies should alert the pathologist to the possibility of HIV associated disease.

Age effects on central nervous system activity reflected in the olfactory event-related potential. Evidence for decline in middle age.

A series of studies in this laboratory using the olfactory event-related potential (OERP) have examined the underlying central nervous system activity associated with age-related changes in olfactory functioning. Early (sensory) components of the OERP showed reduced amplitude and longer latency in elderly subjects, with larger effects in males. Amplitudes are already decreased in middle age. The late cognitive component, P3, showed a longer latency as well as a decreased amplitude in the elderly, with effect sizes for age significantly larger for the late component than for the early components. We report here the significantly longer latency, particularly for the P3, in middle-aged persons, suggesting age-related slowing of olfactory information processing as early as the 50s. Results suggest that the elderly brain, and indeed, the middle-aged brain shows smaller responses to odors, is less able to allocate attentional resources and slows in its olfactory cognitive processing. The OERP is a potent reflection of these changes.

Amino acid neurotransmitters in postmortem human brain analyzed by high performance liquid chromatography with electrochemical detection.

In the present study we have developed a method of measuring putative neurotransmitter amino acids using high performance liquid chromatography (HPLC) with electrochemical detection. The assay had a sensitivity in the low pmol range and sample turnover time was 30 min. The postmortem stability of amino acids was examined in an animal model simulating human autopsy conditions. Aspartate concentrations increased 15% between 4 and 24 h postmortem while gamma-aminobutyric acid (GABA) concentrations rose 35% by 4 h but were stable thereafter. Glutamate and taurine were stable at all time points. The assay has been used to examine concentrations of neurotransmitter amino acids in 15 patients without neurological or psychiatric disease. Results agree well with previous work and knowledge of amino acid neurotransmitter pathways. The current technique provides a reliable method for the study of amino acid transmitter abnormalities in neurological illness.

Results of upper plexus thoracic outlet syndrome operation.

A review of 181 patients with thoracic outlet syndrome treated in our clinic revealed that 22 (12%) showed symptoms of compression of the distal median nerve only. Although there are several distinct anatomic abnormalities involving the upper brachial plexus, a first rib resection using the transaxillary approach was found to relieve these patients' symptoms as well as it did in those who exhibited the classic findings of ulnar nerve paresthesias. A comparison of the patients' outcomes showed no appreciable differences in the results obtained in those with distal median nerve compression symptoms only, lower plexus involvement, or combined upper and lower plexus symptoms.