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Introduction: Glioma, a prevalent and deadly brain tumor, is marked by significant cellular heterogeneity and metabolic alterations. However, the comprehensive cell-of-origin and metabolic landscape in high-grade (Glioblastoma Multiforme, WHO grade IV) and low-grade (Oligoastrocytoma, WHO grade II) gliomas remains elusive. Methods: In this study, we undertook single-cell transcriptome sequencing of these glioma grades to elucidate their cellular and metabolic distinctions. Following the identification of cell types, we compared metabolic pathway activities and gene expressions between high-grade and low-grade gliomas. Results: Notably, astrocytes and oligodendrocyte progenitor cells (OPCs) exhibited the most substantial differences in both metabolic pathways and gene expression, indicative of their distinct origins. The comprehensive analysis identified the most altered metabolic pathways (MCPs) and genes across all cell types, which were further validated against TCGA and CGGA datasets for clinical relevance. Discussion: Crucially, the metabolic enzyme phosphodiesterase 8B (PDE8B) was found to be exclusively expressed and progressively downregulated in astrocytes and OPCs in higher-grade gliomas. This decreased expression identifies PDE8B as a metabolism-related oncogene in IDH-mutant glioma, marking its dual role as both a protective marker for glioma grading and prognosis and as a facilitator in glioma progression. [ABSTRACT FROM AUTHOR]

"Oligoastrocytoma" disappeared as of the revised fourth edition of the World Health Organization Classification of Tumours of the Central Nervous System, except where appended with "not otherwise specified (NOS)". However, histopathological and genetic backgrounds of cases with dual features of astrocytoma/oligodendroglioma have been sparsely reported. We encountered a 54-year-old man with right frontal glioma comprising two distinct parts on imaging and histopathological examination: grade 4 astrocytoma with IDH1-R132H, ATRX loss, p53-positivity and intact 1p/19q; and oligodendroglioma with IDH1-R132H, intact ATRX, p53-negativity and partially deleted 1p/19q. At recurrence, histopathology showed low-grade mixed astrocytic and oligodendroglial features: the former with IDH1-R132H, ATRX loss, p53-positivity and intact 1p/19q and the latter showing IDH1-R132H, intact ATRX, p53-negativity and 1p/19q codeletion. At second recurrence, histopathology was astrocytoma grade 4 with IDH1-R132H, ATRX loss, p53-positivity and intact 1p/19q. Notably, 1p/19q codeletion was acquired at recurrence and CDKN2A was deleted at second recurrence. These findings suggest insights into tumorigenesis: (1) gliomas with two distinct lineages might mix to produce "oligoastrocytoma"; and (2) 1p/19q codeletion and CDKN2A deletion might be acquired during chemo-radiotherapy. Ultimately, astrocytic and oligodendroglial clones might co-exist developmentally or these two lineages might share a common cell-of-origin, with IDH1-R132H as the shared molecular feature. [ABSTRACT FROM AUTHOR]

With increasing life expectancies and population aging, the incidence of elderly patients with grade 2 and 3 gliomas is increasing. However, there is a paucity of knowledge on factors affecting their treatment selection and overall survival (OS). Geriatric patients aged between 60 and 89 years with histologically proven grade 2 and 3 intracranial gliomas were identified from the National Cancer Database between 2010 and 2017. We analyzed patients' demographic data, tumor characteristics, treatment modality, and outcomes. The Kaplan-Meier method was used to analyze OS. Univariate and multivariate analyses were performed to assess the predictive factors of mortality and treatment selection. A total of 6257 patients were identified: 3533 (56.3 %) hexagenerians, 2063 (32.9 %) septuagenarians, and 679 (10.8 %) octogenarians. We identified predictors of lower OS in patients, including demographic factors (older age, non-zero Charlson-Deyo score, non-Hispanic ethnicity), socioeconomic factors (low income, treatment at non-academic centers, government insurance), and tumor-specific factors (higher grade, astrocytoma histology, multifocality). Receiving surgery and chemotherapy were associated with a lower risk of mortality, whereas receiving radiotherapy was not associated with better OS. Our findings provide valuable insights into the complex interplay of demographic, socioeconomic, and tumor-specific factors that influence treatment selection and OS in geriatric grade 2 and 3 gliomas. We found that advancing age correlates with a decrease in OS and a reduced likelihood of undergoing surgery, chemotherapy, or radiotherapy. While receiving surgery and chemotherapy were associated with improved OS, radiotherapy did not exhibit a similar association. [ABSTRACT FROM AUTHOR]

A 12-year and 3-month spayed female mixed cat was presented with severe lumbar pain. Magnetic resonance imaging and postmortem examination revealed a swollen lesion in the spinal cord at L3 level. Histologic examination identified extensive neoplastic cell proliferation with massive necrosis in the tumor tissue. Two types of neoplastic cells were recognized. One type of neoplastic cells were large cells characterized by round to polygonal shape and abundant eosinophilic cytoplasm (referred to as "large cells"). The other neoplastic cells were small, densely proliferated, and had round to irregular shape and scant eosinophilic cytoplasm (referred to as "small cells"). Both types of cells were positive for oligodendrocyte transcription factor 2 and SRY-box transcription factor 10. Glial fibrillary acidic protein was positive in large cells but negative in most small cells. Digital analysis for Ki-67-stained tumor tissues found that total 21.1% ± 6.5% of tumor cells were positive for Ki-67. Based on these findings, we diagnosed malignant oligoastrocytoma in the spinal cord. [ABSTRACT FROM AUTHOR]

Abstract A case of a true dual-genotype IDH-mutant oligoastrocytoma with two different cell types within a single mass in a young woman is presented. Imaging findings of the left frontal infiltrating glioma predicted the two neoplastic components that were identified upon resection. Tissue examination demonstrated areas of tumor with contrasting histologic and molecular features, including specific IDH1, ATRX, TP53, TERT and CIC mutational profiles, consistent with oligodendroglioma and astrocytoma, respectively. The clinical and radiological course over 17 months from first diagnosis included three surgical resections with slow progression of the astrocytic component, and ultimately chemotherapy and radiation treatments were commenced. Reports of the clinical courses for these rare cases of dual-genotype oligoastrocytomas will inform therapy choices, to optimize benefit while minimizing side effects. The steadily increasing number of cases suggests that the neoplasm might be reconsidered as an official entity by the WHO.

Introduction: Glioma, a prevalent and deadly brain tumor, is marked by significant cellular heterogeneity and metabolic alterations. However, the comprehensive cell-of-origin and metabolic landscape in high-grade (Glioblastoma Multiforme, WHO grade IV) and low-grade (Oligoastrocytoma, WHO grade II) gliomas remains elusive., Methods: In this study, we undertook single-cell transcriptome sequencing of these glioma grades to elucidate their cellular and metabolic distinctions. Following the identification of cell types, we compared metabolic pathway activities and gene expressions between high-grade and low-grade gliomas., Results: Notably, astrocytes and oligodendrocyte progenitor cells (OPCs) exhibited the most substantial differences in both metabolic pathways and gene expression, indicative of their distinct origins. The comprehensive analysis identified the most altered metabolic pathways (MCPs) and genes across all cell types, which were further validated against TCGA and CGGA datasets for clinical relevance., Discussion: Crucially, the metabolic enzyme phosphodiesterase 8B (PDE8B) was found to be exclusively expressed and progressively downregulated in astrocytes and OPCs in higher-grade gliomas. This decreased expression identifies PDE8B as a metabolism-related oncogene in IDH-mutant glioma, marking its dual role as both a protective marker for glioma grading and prognosis and as a facilitator in glioma progression., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 He, Peng, Wang, Yang, Zhou, Gong, Song and Wang.)

Purpose: A chromosomal 1p/19q codeletion was included as a required diagnostic component of oligodendrogliomas in the 2016 World Health Organization (WHO) classification of central nervous system tumors. We sought to evaluate disparities in reported testing for 1p/19q codeletion among oligodendroglioma and oligoastrocytoma patients before and after the guidelines. Methods: The National Cancer Database (NCDB) was queried for patients with histologically-confirmed WHO grade II/III oligodendroglioma or oligoastrocytoma from 2011-2017. Adjusted odds of having a reported 1p/19q codeletion test for patient- and hospital-level factors were calculated before (2011-2015) and after (2017) the guidelines. The adjusted likelihood of receiving adjuvant treatment (chemotherapy and/or radiotherapy) based on reported testing was also evaluated. Results: Overall, 6,404 patients were identified. The reported 1p/19q codeletion testing rate increased from 45.8% in 2011 to 59.8% in 2017. From 2011-2015, lack of insurance (OR 0.77; 95% CI 0.62-0.97;p=0.025), lower zip code-level educational attainment (OR 0.62; 95% CI 0.49-0.78;p<0.001), and Northeast (OR 0.68; 95% CI 0.57-0.82;p<0.001) or Southern (OR 0.62; 95% CI 0.49-0.79;p<0.001) facility geographic region were negatively associated with reported testing. In 2017, Black race (OR 0.49; 95% CI 0.26-0.91;p=0.024) and Northeast (OR 0.50; 95% CI 0.30-0.84;p=0.009) or Southern (OR 0.42; 95% CI 0.22-0.78;p=0.007) region were negatively associated with reported testing. Patients with a reported test were more likely to receive adjuvant treatment (OR 1.73; 95% CI 1.46-2.04;p<0.001). Conclusion: Despite the 2016 WHO guidelines, disparities in reported 1p/19q codeletion testing by geographic region persisted while new disparities in race/ethnicity were identified, which may influence oligodendroglioma and oligoastrocytoma patient management. [ABSTRACT FROM AUTHOR]

PurposeA chromosomal 1p/19q codeletion was included as a required diagnostic component of oligodendrogliomas in the 2016 World Health Organization (WHO) classification of central nervous system tumors. We sought to evaluate disparities in reported testing for 1p/19q codeletion among oligodendroglioma and oligoastrocytoma patients before and after the guidelines.MethodsThe National Cancer Database (NCDB) was queried for patients with histologically-confirmed WHO grade II/III oligodendroglioma or oligoastrocytoma from 2011-2017. Adjusted odds of having a reported 1p/19q codeletion test for patient- and hospital-level factors were calculated before (2011-2015) and after (2017) the guidelines. The adjusted likelihood of receiving adjuvant treatment (chemotherapy and/or radiotherapy) based on reported testing was also evaluated.ResultsOverall, 6,404 patients were identified. The reported 1p/19q codeletion testing rate increased from 45.8% in 2011 to 59.8% in 2017. From 2011-2015, lack of insurance (OR 0.77; 95% CI 0.62-0.97;p=0.025), lower zip code-level educational attainment (OR 0.62; 95% CI 0.49-0.78;p

We present a case of a patient with the initial diagnosis of oligoastrocytoma WHO grade II. After multiple previous treatments and transformation to an anaplastic oligoastrocytoma WHO grade III, imaging after radiotherapy showed another tumor progression. Histopathological analysis after tumor resection confirmed parts of an astrocytic and an oligodendroglial tumor with extensive therapy-related changes. This constellation is not sufficiently covered by the current classification system and currently described as a diffuse glioma.

The molecular characteristics of glioma patients, such as 1p/19q codeletion, MGMT promoter region methylation, and IDH1/IDH2 mutations, carry important information for tumor classification, biological behavior, and the prediction of patient survival. We sought to address the clinical characteristics of brain tumor patients in the Taiwanese population. Our aim was to compare the H&E-based classification and the 2016 WHO classification in glioma patients. 192 patients were recruited in this study including glioblastomas (GBMs) and lower-grade gliomas (LGGs). We performed assays to determine the statuses of 1p/19q codeletion, MGMT promoter methylation, and IDH mutations in tumors and assessed their associations with survival time. We also compared the difference between H&E and WHO 2016 classification. Using the H&E classification, the overall survival time (OST) was associated with IDH status in astrocytoma and oligoastrocytoma patients but not in oligodendroglioma and GBM patients. However, OST showed no significant correlation with MGMT promoter methylation in all the groups. Furthermore, no significant association was observed between 1p/19q codeletion and OST in GBM patients. Using the WHO 2016 classification, our results indicated that astrocytoma and oligodendroglioma patients with mutant IDH showed a significantly prolonged OST than patients with wild-type IDH. However, only oligodendroglioma patients with MGMT hypermethylation demonstrated statistically significant difference. Prognostic factors, including the age at diagnosis, IDH mutations, MGMT promoter methylation, and 1p/19q codeletion, could independently predict patient survival. Based on the WHO 2016 classification of glioma, the new histological groups provide a better and objective method to categorize glioma patients and predict patient survival.

The optimal management of patients with low-grade glioma (LGG) is controversial. The controversy largely stems from the lack of well-designed clinical trials with adequate follow-up to account for the relatively long progression-free survival and overall survival of patients with LGG. Nonetheless, the literature increasingly suggests that expectant management is no longer optimal. Rather, there is mounting evidence supporting active management including consideration of surgical resection, radiotherapy, chemotherapy, molecular and histopathologic characterization, and use of modern imaging techniques for monitoring and prognostication. In particular, there is growing evidence favoring extensive surgical resection and increasing interest in the role of chemotherapy (especially temozolomide) in the management of these tumors. In this review, we critically analyze emerging trends in the literature with respect to management of LGG, with particular emphasis on reports published during the past year.

Background Mixed gliomas, such as oligoastrocytomas (OA), anaplastic oligoastrocytomas, and glioblastomas (GBMs) with an oligodendroglial component (GBMO) are defined as tumors composed of a mixture of two distinct neoplastic cell types, astrocytic and oligodendroglial. Recently, mutations ATRX and TP53, and codeletion of 1p/19q are shown to be genetic hallmarks of astrocytic and oligodendroglial tumors, respectively. Subsequent molecular analyses of mixed gliomas preferred the reclassification to either oligodendroglioma or astrocytoma. This study was designed to apply genetically integrated diagnostic criteria to mixed gliomas and determine usefulness and prognostic value of new classification in Korean patients. Methods Fifty-eight cases of mixed OAs and GBMOs were retrieved from the pathology archives of Seoul National University Hospital from 2004 to 2015. Reclassification was performed according to genetic and immunohistochemical properties. Clinicopathological characteristics of each subgroup were evaluated. Overall survival was assessed and compared between subgroups. Results We could reclassify all mixed OAs and GBMOs into either astrocytic or oligodendroglial tumors. Notably, 29 GBMOs could be reclassified into 11 cases of GBM, IDH-mutant, 16 cases of GBM, IDH-wildtype, and two cases of anaplastic oligodendroglioma, IDH mutant. Overall survival was significantly different among these new groups (p

A case of a true dual-genotype IDH-mutant oligoastrocytoma with two different cell types within a single mass in a young woman is presented. Imaging findings of the left frontal infiltrating glioma predicted the two neoplastic components that were identified upon resection. Tissue examination demonstrated areas of tumor with contrasting histologic and molecular features, including specific IDH1, ATRX, TP53, TERT and CIC mutational profiles, consistent with oligodendroglioma and astrocytoma, respectively. The clinical and radiological course over 17 months from first diagnosis included three surgical resections with slow progression of the astrocytic component, and ultimately chemotherapy and radiation treatments were commenced. Reports of the clinical courses for these rare cases of dual-genotype oligoastrocytomas will inform therapy choices, to optimize benefit while minimizing side effects. The steadily increasing number of cases suggests that the neoplasm might be reconsidered as an official entity by the WHO. [ABSTRACT FROM AUTHOR]

Background Super-refractory status epilepticus (SRSE) is a life-threatening neurologic emergency defined as "status epilepticus (SE) that continues 24 hours or more after the onset of anesthesia, including those cases in which the SE recurs on the reduction or withdrawal of anesthesia," which occurs in 10% to 15% of patients with SE and rarely has been resolved surgically. Case Descriptions A 20-year-old man with SRSE and a long history of left parieto-occipital oligoastrocytoma was admitted for convulsive SE that became SRSE and underwent lesionectomy guided by electrocorticography and neuronavigation for local tumor recurrence. Histopathologic diagnosis was oligoastrocytoma. SRSE was aborted and the patient recovered fully without any functional deficits. Conclusions The lesionectomy guided by electrocorticography and neuronavigation should be considered as a treatment option for patients with SRSE. [ABSTRACT FROM AUTHOR]

Background: Extracranial metastasis is a rare phenomenon of anaplastic oligoastrocytoma. When patients progress after comprehensive treatment, there is often no effective treatment. Rapid development of gene detection technology makes precision treatment of glioma possible. Patient and methods: A 22-year-old girl was firstly diagnosed with anaplastic oligoastrocytoma WHO grade III-IV in 2014, and progressed rapidly after chemoradiotherapy in multiple extraneural lesions in 2016. She was expected to have a short life and Next-Generation Sequencing (NGS) was applied. Results: Mutation of BRAF (V600E) was reported by 1st NGS and oral vemurafenib stabilized her disease for 6 months. PIK3CA was reported by 2nd NGS after her progression of vemurafenib. The oral administration of everolimus together with vemurafenib stabilized her disease for another 6 months. However, the patient died due to the rapid progression of the disease on 24 February 2018. Conclusion: We successfully treated a BRAF V600E-mutated anaplastic oligoastrocytoma with multiple extraneural metastases with vemurafenib and everolimus. For late-staged patients who have no clear and effective treatment plan, NGS may serve as an effective option. [ABSTRACT FROM AUTHOR]

Background: Low‐grade gliomas (LGG) are slow‐growing primary brain tumors that typically affect young adults. Advanced age is widely recognized as a poor prognostic factor in LGG. The impact of age on postoperative outcome in this patient group has not been systemically studied. Methods: We performed a nationwide register‐based study with data from the Swedish Brain Tumor Registry (SBTR) for all adults diagnosed with a supratentorial LGG (WHO grade II astrocytoma, oligoastrocytoma, or oligodendroglioma) during 2005‐2015. Patient‐ and tumor‐related characteristics, postoperative complications, and survival were compared between three different age groups (18‐39 years, 40‐59 years, and ≥60 years). Results: We identified 548 patients; 204 patients (37.2%) aged 18‐39 years, 227 patients (41.4%) aged 40‐59 years, and 117 patients (21.4%) ≥60 years of age. Unfavorable preoperative prognostic factors (eg, functional status and neurological deficit) were more common with increased age (P < .001). In addition, overall survival was significantly impaired in those 60 years and above (P < .001). We observed a clear dose‐response for age with separation of survival curves at 50 years. Biopsy was more common in patients ≥60 years (P < .001). Subgroup analysis of patients with resection revealed a higher amount of postoperative neurological deficits in older patients (P = .029). Conclusion: In general, older patients with LGG have several unfavorable prognostic factors compared with younger patients but seem to tolerate surgery in a comparable fashion. However, more neurological deficits were observed following resections in elderly. Our data further support a cutoff at 50 years rather than 40 years for selection of high‐risk patients. [ABSTRACT FROM AUTHOR]

We report a case of meningioma in the left temporal lobe which was successfully treated in our clinic. Howewer, two years later the new tumor was grown in the same temporal lobe. MRi and PET scan demonstrated the oligoastrocytoma of the medial temporal lobe.

Objective Patients with diffuse low-grade gliomas (DLGGs) typically present with seizures. We sought to review the neurosurgical literature for seizure outcome after resection of these tumors. Methods Using PubMed, we identified surgical series reporting seizure freedom rates for grade II astrocytoma, oligoastrocytoma, and oligodendroglioma. Inclusion criteria included seizure outcomes reported specifically for DLGGs and at least 10 patients with follow-up data. Results Twelve articles met the inclusion criteria. The median seizure-free rate after surgery in these patients was 71%, with an interquartile range of 64%–82%. In 10 studies, more than 60% of patients were seizure free. Studies used varying reporting times for seizure outcome determination. In the 6 studies that reported postoperative antiepileptic medication use, 5%–69% of seizure-free patients were weaned off these agents (median, 32%). The durability of seizure freedom has not been clearly studied to date. The most commonly reported prognostic factor for seizure freedom after resection was increasing extent of resection. Conclusions Among articles reporting seizure outcomes after resection of DLGG, the median seizure-free rate was 71% (interquartile range, 64%–82%). Seizure freedom is likely associated with extent of resection. [ABSTRACT FROM AUTHOR]

The diagnosis of 206 low and high grade adult gliomas, including 40 oligoastrocytomas, was revised based on the immunohistochemical reactivity for the ATRX protein, IDH1/ 2 mutation status and 1p/19q chromosomal status. All oligodendrogliomas kept the initial diagnosis. Astrocytomas did not change diagnosis in 30 of 36 cases (83.3 %); four of 36 (11.1 %) cases were reclassified as oligodendroglioma, one (2.8 %) as DNT and the other (2.8 %) as reactive gliosis. Oligoastrocytomas changed diagnosis in 35 of 40 (87.5 %) cases, being reclassified 22 of 40 (55 %) as astrocytoma, 11 of 40 (27.5 %) as oligodendroglioma and two of 40 (5 %) as reactive gliosis. Four (10 %) remained unclassifiable. In one case only (2.5 %), the diagnosis of oligoastrocytoma could not be excluded since tumor astrocytes and tumor oligodendrocytes coexisted in mixed tumor areas. In the GBM tumor subgroup, GBMO disappeared because they were not substantiated by molecular genetics. Pilocytic astrocytomas retained ATRX expression. Loss of nuclear ATRX protein expression was strongly associated to IDH1/ 2 mutations ( p = 0.0001) and mutually exclusive with total 1p/19q co-deletion ( p = 0.0001). In astrocytic tumors, loss of immunoreactivity for the ATRX protein was significantly associated to the ALT phenotype ( p = 0.0003). The constitutive ATRX expression in microglia/macrophages may be misleading, especially in the identification of an oligodendroglial tumor infiltration. Of paramount importance in the recognition of oligodendroglial and astrocytic tumor cells were the double immunostainings for ATRX/GFAP, ATRX/IDH1, ATRX/Iba-1 and ATRX/CD68. [ABSTRACT FROM AUTHOR]

We report a case of pathologically confirmed tumefactive multiple sclerosis (MS) followed shortly thereafter by the diagnosis of an oligoastrocytoma. The complexity of diagnosis and management of concomitant presence of tumefactive MS and glial cell tumors is discussed.

Aims: To assess whether in oligoastrocytomas ATRX deficiency, as a surrogate of the alternative lengthening of telomeres (ALT) pathway, has a role in predicting the presence or absence of loss of heterozygosity (LOH) of 1p and 19q, the genetic signature of oligodendroglial differentiation and a favourable prognostic marker. Methods and results: A series of 54 oligoastrocytomas were investigated by immunohistochemistry as well as microsatellite analysis for LOH 1p19q. Genetic findings were correlated with morphological assessment. Conclusions: ATRX deficiency was mutually exclusive with LOH. Conversely, ATRX-proficient tumours immunoreactive for R132H-mutant isocitrate dehydrogenase 1 (IDH1) showed a high rate (85%) of LOH. A more oligodendroglioma-like morphology was associated with a higher rate of LOH even in the morphologically ambiguous group of oligoastrocytomas. Our findings support the concept that oligoastrocytomas represent a morphological grey zone, rather than a group of truly 'mixed' or 'intermediate' tumours. More precise classification of diffuse gliomas may also improve grading of borderline cases. We propose an immunohistochemical algorithm for classification of morphologically ambiguous diffuse gliomas. [ABSTRACT FROM AUTHOR]

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Although some existing evidence supports the addition of chemotherapy (CT) to radiation therapy (RT) for anaplastic oligodendroglioma treatment, controversy about both the criteria for suitable candidates and the optimal treatment schedule remains. We reviewed data from 376 newly diagnosed anaplastic oliogodendroglial tumor patients from nine Korean institutes were reviewed from 2000 to 2010. Total tumor removal was performed in 146 patients. More than 85 % of the entire patients received postoperative RT, and 59 % received CT. Approximately 50 % (n = 189) received CT in addition to RT and 9 % (n = 32) received CT only. A multivariate analysis revealed that younger age, frontal lobe location of the tumor, gross total removal, 1p/19q codeletion, and initial RT were associated with longer progression-free and overall survival rates. No difference was observed in outcomes from the treatment that included either temozolomide or PCV (procarbazine, lomustine, and vincristine) in addition to RT regardless of the 1p/19q deletion status. A clear improvement in progression-free and overall survival was observed for RT and combined CT/RT in compared with CT only. Postoperative RT appears to improve survival for entire group thus total removal and 1p/19q codeletion may not be sufficient criteria to omit RT as a treatment option. These results suggest that RT should continue to be offered as the standard treatment option for patients with anaplastic oligodendroglial tumors. [ABSTRACT FROM AUTHOR]

This study investigated the treatment of anaplastic oligodendroglial tumors across nine Korean institutions. We reviewed the medical records from 381 patients with histologically confirmed anaplastic oligodendroglioma or anaplastic oligoastrocytoma (AOA) from 2000 to 2010. Clinical factors and treatment patterns were analyzed for each year. Post-operative therapy was performed in 354 patients (94.1 %), of which 133 received radiotherapy (RT) alone and 189 received both RT and chemotherapy. RT alone was the preferred treatment toward the end of the study period (29.4 % in 2000-2001 vs. 56.3 % in 2010, P = 0.005). The use of procarbazine, lomustine, and vincristine (PCV) decreased (57.6 % in 2000-2001 vs. 28.6 % in 2010, P = 0.001) and the use of temozolomide (TMZ) increased (0 % in 2000-2001 vs. 61.9 % in 2010, P < 0.001) over the study period. A combination of chemotherapy and RT was used more often than RT alone in young patients ( P = 0.036) and patients with a good performance status ( P = 0.023). The 1p/19q co-deletion status and O-6-methyguanine-DNA methyltransferase methylation were analyzed since 2004 but were not significant factors for determining whether to administer chemotherapy. Among the patients who received chemotherapy, TMZ was used more often in patients with AOA ( P = 0.007) and PCV was used more often in patients with either multiple lesions ( P = 0.027) or the 1p/19q co-deletion ( P = 0.026). Our results demonstrate that the treatment pattern for oligodendroglial tumors changed significantly across the study period. In particular, TMZ has replaced PCV, and the use of molecular markers as well as RT alone has increased, but a unified protocol remains to be established. [ABSTRACT FROM AUTHOR]

Summary This report describes an oligoastrocytoma in the brain of a 3.5-year-old female pet African hedgehog ( Atelerix albiventris ) that showed progressive central nervous system signs for 6 months. Microscopical examination of the brain revealed a widely infiltrative, deep-seated glioma within the white matter of the cerebral hemispheres, basal nuclei, hippocampus, thalamus, midbrain, pons and the medulla of the cerebellum with extension of neoplastic cells into the cerebral cortex and overlying leptomeninges. Morphological features of the neoplastic cells, together with variable immunohistochemical expression of glial fibrillary acidic protein, Olig-2 and Nogo-A, indicated the presence of intermingled astrocytic and oligodendroglial tumour cells with an astrocytic component of approximately 40% consistent with an oligoastrocytoma. The distribution of the tumour is consistent with gliomatosis cerebri. [ABSTRACT FROM AUTHOR]

Diagnosis of low-grade diffuse gliomas based on morphology is highly subjective and, therefore, is often difficult, with significant intra- and interobserver variability. Here, we investigated WHO grade II diffuse astrocytomas, oligoastrocytomas and oligodendrogliomas for immunohistochemical expression of Olig2, measuring its labeling index (LI), and evaluated the significance of Olig2 LI in the histological and molecular classifications. The means of Olig2 LI in glioma cells were 43.7 % in diffuse astrocytomas, 59.3 % in oligoastrocytomas and 76.1 % in oligodendrogliomas. There was a statistically significant difference between all pairs of histological types. The mean of Olig2 LI of gliomas with 1p/19q loss ± IDH1/2 mutation, the majority of them being oligodendrogliomas, was significantly higher than the means of those with TP53 mutation ± IDH1/2 mutation and IDH1/2 mutation only, the majority of which were diffuse astrocytomas (70.1 vs. 47.2 and 46.5 %, respectively). When categorized according to the classification of Jiao et al., Olig2 LI of I-CF gliomas (cases with IDH and one or more of CIC, FUBP1 or combined 1p/19q loss; mean 71.0 %) was significantly higher than that of I-A gliomas (cases with IDH and ATRX alterations; mean 45.3 %). These molecular classifications were reported to correlate well with clinical outcome. However, borderlines of Olig2 LI were broad and could not clearly distinguish genotypes in the molecular classifications. In conclusion, Olig2 LI cannot be taken as a complete surrogate marker for molecular genotype, but could possibly provide some ancillary information when molecular assay is not availabe. [ABSTRACT FROM AUTHOR]

Astrocytoma and oligodendroglioma are histologically and genetically well-defined entities. The majority of astrocytomas harbor concurrent TP53 and ATRX mutations, while most oligodendrogliomas carry the 1p/19q co-deletion. Both entities share high frequencies of IDH mutations. In contrast, oligoastrocytomas (OA) appear less clearly defined and, therefore, there is an ongoing debate whether these tumors indeed constitute an entity or whether they represent a mixed bag containing both astrocytomas and oligodendrogliomas. We investigated 43 OA diagnosed in different institutions employing histology, immunohistochemistry and in situ hybridization addressing surrogates for the molecular genetic markers IDH1R132H, TP53, ATRX and 1p/19q loss. In all but one OA the combination of nuclear p53 accumulation and ATRX loss was mutually exclusive with 1p/19q co-deletion. In 31/43 OA, only alterations typical for oligodendroglioma were observed, while in 11/43 OA, only indicators for mutations typical for astrocytomas were detected. A single case exhibited a distinct pattern, nuclear expression of p53, ATRX loss, IDH1 mutation and partial 1p/19q loss. However, this was the only patient undergoing radiotherapy prior to surgery, possibly contributing to the acquisition of this uncommon combination. In OA with oligodendroglioma typical alterations, the portions corresponding to astrocytic part were determined as reactive, while in OA with astrocytoma typical alterations the portions corresponding to oligodendroglial differentiation were neoplastic. These data provide strong evidence against the existence of an independent OA entity. [ABSTRACT FROM AUTHOR]

Background Tumours of the central nervous system (CNS) represent a relatively rare but serious health burden. This study provides insight into the incidence and survival patterns of gliomas in the Netherlands diagnosed in adult patients during the time period 1989-2010, with a focus on glioblastoma and low-grade gliomas. Methods Data on 21,085 gliomas (excluding grade I tumours) were obtained from the Netherlands Cancer Registry, including tumours of the CNS without pathological confirmation. We calculated the age-standardised incidence rates and the estimated annual percentage change (EAPC) for all glioma subtypes. Crude and relative survival rates were estimated using information on the vital status obtained from the Dutch Municipal Personal Records Database. Results Incidence of gliomas in adults increased over time, from 4.9 per 100,000 in 1989 to 5.9 in 2010 (EAPC 0.7%, p<0.001). Two thirds were astrocytoma, 10% oligodendroglioma/oligoastrocytoma, 3% ependymoma and 21% were unspecified. Within the group of astrocytic tumours, the proportion of glioblastoma rose, while the proportion of anaplastic and unspecified astrocytoma decreased. Unspecified neoplasms also decreased, but this was significant only after 2005. Over the course of the study period, glioblastoma patients more often received multimodality treatment with chemotherapy concomitant and adjuvant to radiotherapy. The crude two-year survival rate of glioblastoma patients improved significantly, from 5% in the time period 1989-1994 to 15% in 2006-2010, with median survival increasing from 5.5 to 9months. The incidence of low-grade gliomas did not change over time. Survival rates for low-grade oligodendroglial and mixed tumours show a modest improvement. Conclusions The incidence rate for the total group of gliomas slightly increased, with a decrease of anaplastic and unspecified tumours and an increase of glioblastoma. Following the introduction of combined chemoradiation, two-year survival rates for glioblastoma significantly improved. Survival improved for low-grade gliomas except for low-grade astrocytic tumours. [ABSTRACT FROM AUTHOR]