Intratumoral histological and molecular heterogeneity in an adult diffuse glioma.

Adult-type diffuse gliomas are the most prevalent type of malignant adult brain tumors. Intratumoral heterogeneity can hinder accurate diagnosis and subsequent treatment. This case report documents a tumor with intratumoral heterogeneity, both histologically and by methylation analysis, located within the left cerebral hemisphere of a 29-year-old female. She presented after a witnessed generalized tonic clonic seizure at home. Two years prior she had a witnessed seizure; however, no brain imaging was done at the time. Magnetic resonance imaging (MRI), on this admission, showed a mass lesion in the left frontal operculum with poorly identified margins and right-sided midline shift. Sampling from the left temporal lobe showed an IDH-mutant, ATRX-mutant astrocytoma, which appeared grade 4 in the enhancing anterior portion and grade 2 in the left temporal lobe. Methylation analysis confirmed this heterogeneity. In summary, this is an excellent example of tumor heterogeneity both histologically and by molecular analysis. It is probable, given the clinical history of presentation 2 years prior, that this tumor originated as a low-grade glioma and subsequently evolved.

A clinically relevant computed tomography (CT) radiomics strategy for intracranial rodent brain tumour monitoring.

Here, we establish a CT-radiomics based method for application in invasive, orthotopic rodent brain tumour models. Twenty four NOD/SCID mice were implanted with U87R-Luc2 GBM cells and longitudinally imaged via contrast enhanced (CE-CT) imaging. Pyradiomics was employed to extract CT-radiomic features from the tumour-implanted hemisphere and non-tumour-implanted hemisphere of acquired CT-scans. Inter-correlated features were removed (Spearman correlation > 0.85) and remaining features underwent predictive analysis (recursive feature elimination or Boruta algorithm). An area under the curve of the receiver operating characteristic curve was implemented to evaluate radiomic features for their capacity to predict defined outcomes. Firstly, we identified a subset of radiomic features which distinguish the tumour-implanted hemisphere and non- tumour-implanted hemisphere (i.e, tumour presence from normal tissue). Secondly, we successfully translate preclinical CT-radiomic pipelines to GBM patient CT scans (n = 10), identifying similar trends in tumour-specific feature intensities (E.g. 'glszm Zone Entropy'), thereby suggesting a mouse-to-human species conservation (a conservation of radiomic features across species). Thirdly, comparison of features across timepoints identify features which support preclinical tumour detection earlier than is possible by visual assessment of CT scans. This work establishes robust, preclinical CT-radiomic pipelines and describes the application of CE-CT for in-depth orthotopic brain tumour monitoring. Overall we provide evidence for the role of pre-clinical 'discovery' radiomics in the neuro-oncology space.

Comparative analysis of deeply phenotyped GBM cohorts of 'short-term' and 'long-term' survivors.

BACKGROUND: Glioblastoma (GBM) is an aggressive brain cancer that typically results in death in the first 15 months after diagnosis. There have been limited advances in finding new treatments for GBM. In this study, we investigated molecular differences between patients with extremely short (≤ 9 months, Short term survivors, STS) and long survival (≥ 36 months, Long term survivors, LTS). METHODS: Patients were selected from an in-house cohort (GLIOTRAIN-cohort), using defined inclusion criteria (Karnofsky score > 70; age < 70 years old; Stupp protocol as first line treatment, IDH wild type), and a multi-omic analysis of LTS and STS GBM samples was performed. RESULTS: Transcriptomic analysis of tumour samples identified cilium gene signatures as enriched in LTS. Moreover, Immunohistochemical analysis confirmed the presence of cilia in the tumours of LTS. Notably, reverse phase protein array analysis (RPPA) demonstrated increased phosphorylated GAB1 (Y627), SRC (Y527), BCL2 (S70) and RAF (S338) protein expression in STS compared to LTS. Next, we identified 25 unique master regulators (MR) and 13 transcription factors (TFs) belonging to ontologies of integrin signalling and cell cycle to be upregulated in STS. CONCLUSION: Overall, comparison of STS and LTS GBM patients, identifies novel biomarkers and potential actionable therapeutic targets for the management of GBM.

Brain biopsy in neurological disease of unknown etiology: A single-center 12-year retrospective analysis.

There are no international guidelines for brain biopsy in neurological disease of unknown etiology, yet most practicing neurologists will encounter difficult cases in which biopsy is considered. This patient cohort is heterogenous, and it is unclear in which circumstances biopsy is most useful. We performed an audit of brain biopsies reviewed in our neuropathology department from 2010 to 2021. Of 9,488 biopsies, 331 biopsies undertaken for an undiagnosed neurological disease were identified. Where documented, the commonest symptoms were hemorrhage, encephalopathy, and dementia. 29% of biopsies were non-diagnostic. The most common clinically relevant findings on biopsy were infection, cerebral amyloid angiopathy with or without angiitis, and demyelination. Rarer conditions included CNS vasculitis, non-infectious encephalitis, and Creutzfeldt Jakob Disease. We highlight the value of brain biopsy in the workup of cryptogenic neurological disease despite recent advances in less invasive diagnostics.

Establishing a committee for antemortem reviews of suspect Creutzfeldt-Jakob disease cases in Ireland.

BACKGROUND: Creutzfeldt-Jakob disease (CJD) is a rapidly progressive, neurodegenerative disease. In Ireland, clinical diagnostics and laboratory testing remain the responsibility of the managing clinician and the Neuropathology Department at the Beaumont Hospital, respectively. Centralized review of individual cases is not undertaken. AIMS: To determine how diagnostic processes for CJD could be improved in Ireland and to outline the structure and referral process for a new CJD review panel at the Beaumont Hospital. METHODS: We surveyed Irish neurologists' experiences on the management of CJD in Ireland. We measured turnaround times (TAT) for CSF samples referred for diagnostic CJD testing. Finally, we retrospectively reviewed imaging of autopsy-proven CJD cases to compare with initial reports. RESULTS: Ninety-three percent of neurologists supported a national central review of suspect CJD cases. A second clinical opinion was considered to be of likely benefit by 79%. Additionally, 93% reported that a centralized review of neuroradiology would be useful. All respondents felt that expediting turnaround of CSF analysis would be of benefit. The average TAT for CSF testing was 35.4 days. In retrospective review of imaging, all patients demonstrated MRI findings consistent with CJD. However, in only one of these cases were the initial pre-autopsy radiological findings reported as being consistent with CJD. CONCLUSIONS: These findings support the need for improvements to the Irish National CJD Surveillance Unit to maximize antemortem diagnostic accuracy. On foot of this, a clinical CJD Multidisciplinary Team (CJD MDT) has been established to provide a second opinion on (i) the patient's clinical history, (ii) neuroradiology and (iii) and neurophysiology reports (where available).

Intracranial haemorrhage and falls: cause or effect?

INTRODUCTION: A difficult question in autopsy practice is whether intracranial haemorrhage has resulted from or brought about a fall. MATERIAL AND METHODS: To address this we undertook a retrospective study of all autopsy reports (N = 2126) complied over a 10 year period (2009-2018). Of 720 patients who underwent a comprehensive post mortem neuropathologic examination we found 226 patients who had a history of a fall. RESULTS: Of the 226 with a history of fall, 175 (79%) had an intracranial haemorrhage which was classified as truamatic (n = 134, 77%) or spontaneous (n = 41, 23%. Within the traumatic group, falls from a standing height (51%) were more common than falls involving stairs (31%) or falls from a height (12%). Cerebral contusional injury (51%) and subdural haemorrhage (45%) were the most common type of haemorrhage in the traumatic group. In the spontaneous haemorrhage group cerebral amyloid angiopathy (49%) was the commonest detected cause and was typically lobar in distribution). CONCLUSION: We are of the view that a comprehensive analysis of fatal falls with intracranial haemorrhage warrants a detailed neuropathologic examination as part of the overall death analysis.

Multicystic Encephalomalacia: The Neuropathology of Systemic Neonatal Parechovirus Infection.

The Neuropathology of Human Parechovirus (HPeV) is not widely described due to the relatively recent discovery of the virus combined with a limited number of autopsy case reports. We report the case of an infant boy born at 38 weeks who, six days after birth, presented with fever and severe neurological dysfunction. Human Parechovirus Type 3 (HPeV3) RNA was detected in his cerebrospinal fluid (CSF) and blood. He died five days after his initial presentation. Neuropathologic examination demonstrated multicystic encephalomalacia (ME). This case report confirms that white matter pathology is dominant in HPeV3 infection. A unique feature, of HPeV encephalomalacia is absence of CSF pleocytosis and minimal inflammation in the meninges. The findings permit comment on the pathogenesis of brain injury by this virus.

Diagnostic Accuracy of Prion Disease Biomarkers in Iatrogenic Creutzfeldt-Jakob Disease.

Human prion diseases are classified into sporadic, genetic, and acquired forms. Within this last group, iatrogenic Creutzfeldt-Jakob disease (iCJD) is caused by human-to-human transmission through surgical and medical procedures. After reaching an incidence peak in the 1990s, it is believed that the iCJD historical period is probably coming to an end, thanks to lessons learnt from past infection sources that promoted new prion prevention and decontamination protocols. At this point, we sought to characterise the biomarker profile of iCJD and compare it to that of sporadic CJD (sCJD) for determining the value of available diagnostic tools in promptly recognising iCJD cases. To that end, we collected 23 iCJD samples from seven national CJD surveillance centres and analysed the electroencephalogram and neuroimaging data together with a panel of seven CSF biomarkers: 14-3-3, total tau, phosphorylated/total tau ratio, alpha-synuclein, neurofilament light, YKL-40, and real-time quaking induced conversion of prion protein. Using the cut-off values established for sCJD, we found the sensitivities of these biomarkers for iCJD to be similar to those described for sCJD. Given the limited relevant information on this issue to date, the present study validates the use of current sCJD biomarkers for the diagnosis of future iCJD cases.

Impact of the 2016 World Health Organization Classification of Tumours of the Central Nervous System: an Irish experience.

The 2016 World Health Organization Classification of Tumours of the Central Nervous System Tumours represents the most significant update to neuro-oncological tumour classification to date, compared with previous updates. This update reflects the substantial advances in molecular and genetic understanding of both adult and childhood brain tumours which have occurred in recent years. These advances have meant that an increasing array of molecular tests are required to definitively classify a tumour, allowing for a more precise integrated pathological diagnosis, but at the expense of a more challenging pathology workup. We review the changes incorporated into the 2016 classification and describe the impact of these changes in an Irish neuropathology laboratory.

Evaluation of the specificity of the central diagnostic criterion for chronic traumatic encephalopathy.

INTRODUCTION: Chronic traumatic encephalopathy (CTE) is a postmortem diagnosis. Consensus postmortem, but not antemortem, diagnostic criteria have been established. A key factor in these criteria is evidence of phosphorylated-tau (p-tau) around sulcal vessels in the cortex. However, this sign has been observed anecdotally in a diverse range of neurodegenerative diseases (NDD). We therefore hypothesise that this criterion may lack specificity. METHODS: To test this, we assessed patients with NDD, but no documented history of brain trauma, for sulcal p-tau. Tissue was retrieved from Dublin Brain Bank (known NDD n = 17; control with no diagnosed NDD n = 6; CTE n = 1), and slides were prepared from three sites with a predilection for trauma: superior frontal gyrus, temporal pole, and superior temporal gyrus. We stained the resulting anonymised slides with both hemotoxylin and eosin (H&E) and p-tau. Three neuropathologists, blinded to the clinical history and neuropathological diagnosis in each instance, evaluated each case for sulcal p-tau. We calculated the interrater agreement, using Fleiss's kappa, and the specificity of this neuropathological sign. RESULTS: Sulcal p-tau was highly specific to diagnosed CTE cases (specificity 0.98), with moderate interrater agreement (κ = 0.45). CONCLUSION: In conclusion, therefore, we observed sulcal p-tau to be a sign highly specific to CTE when compared with NDD cases in the absence of head trauma.

CJD surveillance in the Republic of Ireland from 2005 to 2015: a suggested algorithm for referrals.

Definitive diagnosis of Creutzfeldt Jakob disease (CJD) remains tissue-based. Possible and probable CJD are useful clinical terms but may be used indiscriminately. The aim of this study was to assess the effectiveness of the Irish surveillance system and to ascertain how diagnostic accuracy in identifying clinically "definite" cases might be improved. We reviewed the clinical information, relevant investigations, and samples n = 100; (autopsy n = 87; biopsy n = 13) in 96 patients between January 1, 2005 and December 31, 2015. In 4 cases both a biopsy and autopsy were performed. CJD was confirmed in 50 patients (45 at autopsy and 5 at biopsy). Sporadic CJD (sCJD) accounted for 90% of cases (n = 45); variant CJD (vCJD) for 6% (n = 3) with 1 case each of familial CJD and iatrogenic CJD. CSF 14-3-3, EEG, and MRI investigations were helpful but not available on all patients. CJD mimics (n = 46) fell into the following categories: neurodegenerative (n = 22), immune mediated (n = 3), cerebrovascular disease (n = 5), tumor (n = 5), dual pathology (n = 3), and miscellaneous (n = 8). The Irish surveillance system fulfils its main objective as all clinically suspicious cases are being referred. CJD was confirmed in 52% (n = 50/96) of referrals. Based on this, we propose an algorithm for CJD referrals to reduce both infection control and diagnostic difficulties encountered in CJD surveillance.
.

Genetic features of oligodendrogliomas and presence of seizures. The relationship of seizures and genetics in LGOs.

Low grade oligodendrogliomas (LGO) are diffusely infiltrating World Health Organization (WHO) grade II gliomas, 20 - 30% of which show contrast enhancement. Seizures are a common presenting feature. It has been suggested that 1p19q co-deletion is associated with occurrence of seizures in adults, however, to date, the relationship of tumor genetics and seizure activity has not been extensively investigated. We sought to assess the influence of 1p19q co-deletion, IDH1-R132H positivity, and radiological variables on seizure activity in LGO patients. Specifically, we examined whether these characteristics were associated with seizure at initial presentation, or if they could predict outcome in terms of seizure free survival. In 62 LGOs, neither tumor location nor tumor enhancement were associated with seizures. 1p19q co-deletion status did not predict seizures when controlled for mutant IDH1-R132H expression, tumor location, or enhancement status (odds ratio (OR) 0.9, 95% confidence interval (CI) 0.1 - 4.3). This study, although of limited statistical power, did not demonstrate an association between 1p19q status and seizure occurrence in LGO's. Replication in a larger cohort would further support our hypothesis that 1p19q status alone cannot be used as a reliable predictor of seizure occurrence in LGO's.

Loss of chromosome 1p/19q in oligodendroglial tumors: refinement of chromosomal critical regions and evaluation of internexin immunostaining as a surrogate marker.

Loss of chromosome 1p/19q in oligodendrogliomas represents a powerful predictor of good prognosis. Expression of internexin (INA), a neuronal specific intermediate filament protein, has recently been proposed as a surrogate marker for 1p/19q deletion based on the high degree of correlation between both parameters in oligodendrogliomas. The aim of this study was to assess further the diagnostic utility of INA expression in a set of genetically well-characterized oligodendrogliomas. On the basis of a conservative approach for copy number determination, using both comparative genomic hybridization and fluorescent in situ hybridization, INA expression as a surrogate marker for 1p/19q loss had both reduced specificity (80%) and sensitivity (79%) compared with respective values of 86% and 96% reported in the previous report. The histologic interpretation and diagnostic value of INA expression in oligodendrogliomas should therefore be assessed with greater caution when compared with 1p/19q DNA copy number analysis. In addition, DNA copy number aberrations of chromosomes 10, 16, and 17 were detected exclusively in 1p/19q codeleted samples, suggesting that other regions of the genome may contribute to the 1p/19q-deleted tumor phenotype inthese samples.

Creutzfeldt-Jakob disease in Ireland: epidemiological aspects 1980-2002.

Surveillance for Creutzfeldt-Jakob disease (CJD) has been carried out in the Republic of Ireland since 1980. Initial surveillance was passive and based on consented autopsy confirmation of CJD in patients in whom there was a high index of clinical suspicion. Since 1999, an active surveillance programme involving formal notification of all suspect CJD cases has been in place. The annual mortality rate has increased from 0.34 cases/million in 1980 to 1.27 cases/million in 2001. In all, 29 cases have been pathologically confirmed: 1 had variant CJD (vCJD), 1 had iatrogenic human growth hormone-induced CJD and 1 had fatal insomnia. Sporadic CJD (sCJD) accounted for the remainder. This paper details the change in incidence over 22 years as the surveillance programme in Ireland got under way; the increased incidence is attributed to better case ascertainment, as has occurred in other countries where active surveillance programmes have been established.