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The cIMPACT-NOW Update 7 has replaced the WHO nosology of "ependymoma, RELA fusion positive" by "Supratentorial-ependymoma, C11orf95-fusion positive". This modification reinforces the idea that supratentorial-ependymomas exhibiting fusion that implicates the C11orf95 (now called ZFTA) gene with or without the RELA gene, represent the same histomolecular entity. A hot off the press molecular study has identified distinct clusters of the DNA methylation class of ZFTA fusion-positive tumors. Interestingly, clusters 2 and 4 comprised tumors of different morphologies, with various ZFTA fusions without involvement of RELA. In this paper, we present a detailed series of thirteen cases of non-RELA ZFTA-fused supratentorial tumors with extensive clinical, radiological, histopathological, immunohistochemical, genetic and epigenetic (DNA methylation profiling) characterization. Contrary to the age of onset and MRI aspects similar to RELA fusion-positive EPN, we noted significant histopathological heterogeneity (pleomorphic xanthoastrocytoma-like, astroblastoma-like, ependymoma-like, and even sarcoma-like patterns) in this cohort. Immunophenotypically, these NFκB immunonegative tumors expressed GFAP variably, but EMA constantly and L1CAM frequently. Different gene partners were fused with ZFTA: NCOA1/2, MAML2 and for the first time MN1. These tumors had epigenetic homologies within the DNA methylation class of ependymomas-RELA and were classified as satellite clusters 2 and 4. Cluster 2 (n = 9) corresponded to tumors with classic ependymal histological features (n = 4) but also had astroblastic features (n = 5). Various types of ZFTA fusions were associated with cluster 2, but as in the original report, ZFTA:MAML2 fusion was frequent. Cluster 4 was enriched with sarcoma-like tumors. Moreover, we reported a novel anatomy of three ZFTA:NCOA1/2 fusions with only 1 ZFTA zinc finger domain in the putative fusion protein, whereas all previously reported non-RELA ZFTA fusions have 4 ZFTA zinc fingers. All three cases presented a sarcoma-like morphology. This genotype/phenotype association requires further studies for confirmation. Our series is the first to extensively characterize this new subset of supratentorial ZFTA-fused ependymomas and highlights the usefulness of ZFTA FISH analysis to confirm the existence of a rearrangement without RELA abnormality., (© 2021. The Author(s).)

Background: The management of high-grade glioma (HGG) has been affected by recent landmark trials and is now more proactive. More aggressive treatment leads to hospitalization due to side effects, however. Space-occupying tumor bed cysts have been described, but not systematically assessed. We sought to analyze this complication in a contemporary HGG cohort., Methods: We performed a retrospective review of patients with HGG treated between 2007 and 2013, identified patients with space-occupying tumor bed cysts, and reviewed their hospital notes for relevant variables. Statistical analyses were performed, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated., Results: Tumor bed cysts were found in 12 of 282 patients (4%). The main symptoms were increased intracranial pressure (n = 11), new focal deficits (n = 6), and pseudomeningocele (n = 3), presenting at a median of 19 days since the last resection. Cysts were treated with cystoperitoneal (n = 7) and ventriculoperitoneal (n = 5) shunts, resulting in clinical benefit in 75% of those treated. Intraoperative opening of ventricles is a risk factor, with an OR of 39.339. We propose a classification system comprising 3 cyst types: isolated cyst, cyst with local cerebrospinal fluid (CSF) disturbance, and cyst with global CSF disturbance., Conclusions: In modern neuro-oncology, the rate of tumor bed cysts complicating HGG management appears stable compared with historical data. Shunt implantation is feasible and effective. We propose a classification system as a common data element for comparison across future studies., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The latest World Health Organization (WHO) classification of tumors of the central nervous system (CNS) integrates both histological and molecular features in the definition of diagnostic entities. This new approach enrolls novel entities of gliomas. In this study, we aimed to reveal the epidemiological characteristics, including age at diagnosis, gender ratio, tumor distribution and survival, of these new entities. We retrospectively reclassified 1210 glioma samples according to the 2016 CNS WHO diagnostic criteria. In our cohort, glioblastoma multiforme (GBM) with wildtype isocitrate dehydrogenase (IDH) was the most common malignant tumor in the brain. Almost all gliomas were more prevalent in males, especially in the cluster of WHO grade III gliomas and IDH-wildtype GBM. Age at diagnosis was directly proportional to tumor grade. With respect to the distribution by histology, we found that gliomas concurrent with IDH-mutant and 1p/19q-codeleted or with single IDH-mutant were mainly distributed in frontal lobe, while those with IDH-wildtype were dominant in temporal lobe. Lesions located in insular lobe were more likely to be IDH-mutant astrocytoma. In summary, our results elucidated the epidemiological characteristics as well as the regional constituents of these new gliomas entities, which could bring insights into tumorigenesis and personalized treatment of Chinese glioma population.

Background/aim: Meningioma is the most frequent meningeal neoplasm, usually without relapse or metastasis. Patient follow-up is challenging, not standardized and is decided in multidisciplinary case discussion. Our aim was to determine the clinical and histological factors influencing the time to relapse., Patients and Methods: We conducted a single-Center retrospective study on 38 patients with surgically-excised relapsing meningiomas and collected clinical and pathological data., Results: Our results show that none of the histological factors included in the WHO classification, nor those not included are related to a shorter time to relapse., Conclusion: In our study, none of the histological, immunohistochemical and clinical parameters evaluated seem to be able to predict the time to relapse in meningioma., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Management of gliomas depends on histological diagnosis; there are, however, limitations to the systems presently used. Tumors in the same entity can have different clinical courses, especially when they are diagnosed as WHO grade II-III. Previous studies revealed that genetic subgrouping of gliomas provides useful information that could help establishment of treatment procedures on the basis of the genetic background of the tumors. Recently, the authors analyzed the chromosomal copy number aberrations (CNAs) of adult supratentorial gliomas by comparative genomic hybridization using microdissected tissue sections. The tumors were classified into subgroups according to chromosomal CNAs. WHO grade II-III gliomas contained a variety of genetic subgroups that correlated well with the clinical course. Of these, long progression-free survival was observed for tumors with +7q and those with -1p/19q, low-grade tumors of 2 major lineages, and, in our preliminary data, both were closely correlated with mutation of IDH1. Furthermore, in contrast with +7q tumors, the great majority of +7 or +7/-10q groups had wildtype IDH1. Genetic studies suggest that cytogenetic characterization may provide an additional classification system for gliomas, and new criteria could help to establish rational and objective means for analysis of treatment procedures.

Supratentorial hemispheric diffuse low-grade gliomas (LGGs), i.e., World Health Organization grade II gliomas, are a heterogeneous group of tumors. During their natural course, LGGs tend to progress to a higher grade of malignancy, leading to neurological disability and ultimately to death. In this review, we will show, that during their low-grade period, these tumors exhibit systematically a spontaneous and continuous radiological growth, whatever their histological subtypes. The radiological tumor growth is easily quantified by measuring the evolution of the equivalent tumor diameter (calculated from the tumor volume), obtaining the velocity of diametric expansion (VDE). The spontaneous VDE of LGGs varies markedly with an average VDE of about 4 mm/year. It depends on intrinsic factors (1p19q codeletion status, P53 overexpression status) and can be modified by extrinsic factors (pregnancy). The spontaneous VDE carries a strong prognostic significance regarding progression-free and overall survivals. As a consequence, VDE should be integrated along with the other "static" parameters (multimodal imaging, histological and molecular analyses) in the initial investigations. In addition, the assessment of VDE obtained before, during, and after a particular oncological treatment helps in analyzing their effects on LGGs on an individual basis, helping to guide the decision making.

Object: In this study, the authors address whether neurofilament protein (NFP) expression can be used as an independent prognostic factor in primary glioblastoma multiformes (GBMs)., Methods: Three hundred and two consecutive adult patients with newly diagnosed supratentorial primary GBMs were analyzed (January 2000-August 2008). Detailed data regarding clinical, imaging, and pathological findings, oncological treatments, and outcomes were recorded. Neurofilament protein immunoexpression served to identify NFP-positive tumor cells (normal entrapped neurons and mature ganglion-like cells excluded)., Results: Neurofilament-positive cells were identified in 177 GBMs (58.6%). Patients with NFP-positive GBMs were younger (p < 0.0001), and their GBMs presented with more temporal lobe tumor localization (p = 0.029) and more cortical involvement (p = 0.0003). Neurofilament-negative GBMs presented with more ventricular contact (p < 0.0001) and more tumor midline crossing (p = 0.03). Median overall survival and progression-free survival (PFS) were 13.0 and 7.6 months, respectively, for NFP-positive GBMs, and 7.0 and 5.1 months, respectively, for NFP-negative GBMs. Multivariate analysis revealed NFP immunoexpression, tumor midline crossing, complete resection, and radiotherapy combined with chemotherapy as independent factors associated with overall survival. Neurofilament protein-positive immunoexpression was associated with longer overall survival (hazard ratio [HR] 0.54, 95% CI 0.40-0.74; p < 0.0001) and longer PFS (HR 0.71, 95% CI 0.53-0.96; p = 0.02)., Conclusions: Neurofilament protein-positive immunoexpression represents a strong, therapeutically independent prognostic factor for primary supratentorial GBM clinical outcome among adult patients. Neurofilament protein-GBM's unique pathological features are not only associated with distinct clinical and anatomical behavior, but are also predictive of overall patient survival and PFS. Neurofilament protein immunoexpression may help identify a distinct subgroup of primary GBMs with a favorable prognosis, which should be considered in the design of future targeted therapies.

The natural morphological growth and invasion of World Health Organization (WHO) grade II glioma has not been well documented in previous literature. This study retrospectively analysed the morphological invasive characteristics of adult. Data from 20 patients (15 men, 5 women; mean age, 38 years; age range, 22-64 years), who had supratentorial WHO grade II gliomas and consecutively underwent serial preoperative conventional MR examinations were retrospectively analysed, for change in location, and evidence of haemorrhage, enhancement, necrosis, peri-tumoural oedema and mass effect. Seven tumours, initially located in the grey matter (3, insula; 4, frontal cortices), expanded without definite invasion along fibres. Thirteen tumours, originated from the junction of grey and white matter, invaded in different orientations (4, contralateral invasion; 1, ipsilateral remote dissemination; 8, ipsilateral invasion via the surrounding fibres). The increased proportion of haemorrhage, enhancement, necrosis, peri-tumoural oedema and mass effect in the first and last pre-operative examinations were 14% (1/7), 29% (2/7), 43% (3/7), 43% (3/7) and 29% (2/7), respectively, for the 7 tumours initially located in grey matter, and 15% (2/13), 38% (5/13), 31% (4/13), 15% (2/13) and 38% (5/13) respectively for the 13 tumours initially located at the junction of grey and white matter. The growth of supratentorial WHO grade II glioma is a complicated process. The growth directionality may be determined by initial tumour location.

The objective of the present study was investigation of the possible role of proton magnetic resonance spectroscopy ((1)H-MRS) for differential diagnosis of suprasellar tumors. Forty patients (23 men and 17 women; median age, 45 years) with suprasellar, hypothalamic, and third ventricle neoplasms underwent long-echo (TR: 2000 ms, TE: 136 ms, 128-256 acquisitions) single-voxel (1)H-MRS before surgical treatment. The volume of the voxel was either 3.4 cc or 8 cc. Spectroscopic data were analyzed by calculation of the various metabolite ratios as well as by determination of the type of the pathological (1)H-MR spectra. There were 19 pituitary adenomas, 7 gliomas, 5 craniopharyngiomas, 3 chordomas, meningioma, hemangiopericytoma, malignant lymphoma, germinoma, Rathke cleft cyst, and hypothalamic hamartoma (one of each). Six tumors were recurrent after initial surgical resection with or without irradiation. Comparison of the individual metabolite ratios revealed only few subtle differences among neoplasms. In the same time, pattern analysis with determination of the type of the pathological (1)H-MR spectra disclosed certain specific characteristics, which seemingly can be used for tumor typing. Meanwhile, metabolic imaging was less effective for characterization of recurrent neoplasms. In conclusion, in cases of initially diagnosed suprasellar tumors with involvement of the hypothalamus and extension into the third ventricle pattern analysis of the single-voxel (1)H-MRS can provide valuable information, which, in addition to structural MRI, can be effectively used for diagnostic purposes.

Objective: The purpose of this study is to present our experience with ten cases of Central nervous system atypical teratoid rhabdoid tumor (CNS/ATRT)., Patients and Methods: A series of ten patients with CNS/ATRT, were diagnosed and treated between 1990 and 2005, at the National Institute of Pediatrics, in Mexico City. The gender, age of presentation, clinical features, tumor localization, imaging studies, grade of tumor resection, complications, adjuvant therapy, and survival are presented., Results: The mean age at diagnosis was 37.8 months, seven cases were male, and their average clinical course was 1.3 months. The more common clinical presentation was intracranial hypertension with cranial nerve deficits; location was infratentorial in four patients and supratentorial in six. Hydrocephalus was present as the most common complication (seven cases). In nine patients, the grade of resection was total or subtotal. In one case, it was only possible to perform a biopsy. There were two cases with longer survival (9 and 16 months), and their tumors were resected in total or subtotal manner and received adjuvant therapy (radiotherapy and chemotherapy)., Conclusions: Preliminary results, show that in older children, we can improve their survival with the subtotal or total resection of the tumor and the addition of chemotherapy and radiotherapy.

We report unusual distinctive histopathological features in malignant supratentorial tumours of two infants (patient 1: congenital, patient 2: 30 months). Both patients had paraventricularly located well-delineated tumours. Gross total resection could be performed and postoperative chemotherapy was administered. At the last follow-up, 18 (patient 1) and 10 months (patient 2) postoperatively, both patients were in continuous complete remission. Histologically, both tumours were characterized by high cellular density and monomorphic appearance. Tumour cells were small to medium-sized and the majority of cells showed a distinctive minigemistocytic shape. A small fraction of cells lacked a distinct cytoplasm. Mitotic figures were abundant, tumour necrosis and hypertrophic vascular proliferations were absent. Immunohistochemically, the tumour cells expressed glial (GFAP, S100) and focally neuronal (NFP) proteins. Comparative genomic hybridization showed few, dissimilar chromosomal aberrations in the two tumours. Although sharp demarcation and monomorphic architecture of both tumours are reminiscent of a primitive neuroectodermal tumour, cytological and immunohistochemical glial differentiation refer to a glial tumour origin. To our knowledge the histopathological features of the described tumours do not correspond unequivocally to any established glioma variant and could represent a distinctive new glioma subtype.

To optimize treatment strategies for patients with glioblastoma, a more precise understanding of the molecular basis of this disease clearly is necessary. Therefore, numerous studies have focused on the molecular biology of glioblastoma and its linkage to clinical behavior. Here we investigated 70 glioblastomas using the array-based comparative genomic hybridization (array-CGH) with GenoSensor Array 300 to identify recurrent DNA copy number imbalances associated with patient outcomes. Univariate log-rank analysis of array-CGH data revealed 46 copy number aberrations (CNAs) associated with outcome. Among them, 26 CNAs were associated with shortened survival whereas the remaining 20 CNAs correlated with good prognosis. A hierarchical cluster analysis disclosed two genetically distinct groups of glioblastomas (1 and 2; 56 and 14 tumors, respectively). Univariate log-rank test discerned significant difference in survival between both genetic subsets while the 5-year survival rate consisted of 0 for group 1 and 63% for group 2. Multivariate analysis revealed that unfavorable genetic signature is an independent prognostic factor increasing a risk of patient death (hazard ratio, 4.38; P=0.00001). In conclusion, our current study suggests that glioblastomas can be subdivided into clinically relevant genetic subsets. Therefore, array-CGH screening of glioblastomas could provide clinically useful information and, perhaps, potentially improve the quality of treatment.

Background: Detailed long-term outcome data are not available for adult patients with World Health Organization (WHO) Grade 2 astrocytoma or oligoastrocytoma., Methods: A previously published short-term data set of 239 adult patients with circumscribed de novo supratentorial astrocytoma (187 patients) and oligoastrocytoma (52 patients) treated with interstitial iodine-125 ((125)I) radiosurgery as primary treatment (1979-1992) was revisited. Survival, progression-free survival, functionally independent survival, postrecurrence survival, and time to malignant transformation were estimated with the Kaplan-Meier method. Prognostic factors were obtained from the Cox multivariate proportional hazards model., Results: Five-, 10-, and 15-year survival was 56%, 37%, and 26%, respectively (median follow-up, 10.3 yrs). Progression-free survival was 45%, 21%, and 14%, respectively. The corresponding malignant transformation rates were 33%, 54%, and 67%. No leveling off of the Kaplan-Meier curves could be observed for any of the chosen endpoints. Age > 50 years, a tumor volume > 20 mL, and/or a Karnofsky score < or = 80 were associated with decreased survival or progression-free survival. Age > 35 years and/or a tumor volume > 20 mL increased risk of malignant transformation. Prognostic factors determined subsets of patients with 10-year survival ranging from as low as 6% to as high as 55% and progression-free survival ranging 1-31%., Conclusions: Long-term tumor stabilization is rare. As outcome is mainly determined by treatment-independent factors, minimization of any treatment-related risk must be considered essential., ((c) 2006 American Cancer Society.)

Objective: The authors tested the hypothesis that among Grade II astrocytomas with a particularly long seizure history, a subgroup is hidden with a different prognosis and possibly histological characteristics. To do so, clinical and histological characteristics of two groups of World Health Organization Grade II astrocytoma patients were analyzed: the long-term epilepsy-associated tumor (LEAT) astrocytoma group, with a mean duration of 12.5 years of seizures (n = 19), and the ordinary astrocytomas (n = 87), with a mean length of seizure history of 1.5 years (Non-LEAT)., Methods: All astrocytomas operated on between 1988 and 1999 were collected and followed up for 2 to 13 years (median, 7.0 yr). The 19 LEAT astrocytomas belonged to a group of 207 long-term epilepsy-associated tumors from the epilepsy surgery program. The 87 Non-LEAT cases were 60 so-called ordinary or diffuse World Health Organization Grade II astrocytomas and 27 oligoastrocytomas without long-term epilepsy operated on during the same time period. All tumor cases have been reviewed and partly reclassified as a result of the use of modern immunohistochemical techniques. Statistical analyses for possible discriminating factors included chi(2) test, Fisher's exact test, Kaplan-Meier curves, and multifactorial analysis., Results: Histological subtyping revealed a possible new isomorphic astrocytoma subtype in seven patients. By use of Kaplan-Meier curves, this isomorphic subtype had 50% fewer recurrences at 7.5 years and an estimated long-term survival of 80%. LEAT astrocytomas differed from ordinary Non-LEAT astrocytomas in overall length of history, younger age at first seizure, and higher percentage of 10-year survivors (80%). Temporal location did not influence outcome, and the presence of epilepsy per se was also not a prognostic factor., Conclusion: Differences between astrocytomas with a very long seizure history and those with a very short seizure history do exist. Significant factors for prognosis were age at surgery and presence of postoperative tumor residue but not the presence of epilepsy per se. A new subtype of astrocytomas, provisionally called isomorphic LEA astrocytoma, has putatively been identified with significantly better survival and lower recurrence rate. The negative prognostic factor of a gemistocytic differentiation pattern in diffuse astrocytomas was confirmed.

The concept of different genetic pathways leading to glioblastoma multiforme (GBM) has gained considerable acceptance, and two major groups are now described, primary or de novo GBM and secondary GBM. The present study was undertaken to elucidate whether additional pathways exist and to determine whether there is any correlation between these different variants and clinical parameters, such as age, duration of symptoms, and outcome. For this purpose, immunophenotyping was performed to study the simultaneous expression of p53 protein and epidermal growth factor receptor (EGFR) in 58 cases of adult supratentorial GBM. By this method, four variants of GBM could be distinguished: 34% were p53 positive only, 38% were EGFR positive only, 14% were double negative (p53 negative/EGFR negative), and 14% were double positive (p53 positive/EGFR positive). Interestingly, all nine cases of secondary GBM in which there was clinical and histological evidence of progression from a preexisting low-grade lesion were p53 positive. Differences were observed with regard to the age distribution of the four variants, in that the p53 negative/EGFR negative tumors occurred most frequently in the younger age group (21-40 years). In the elderly group (61-80 years), two-thirds of the tumors were p53 negative/EGFR positive primary GBMs, and no case of the double positive or double negative variant was encountered. The differences in duration of symptoms and symptom-free survival according to age group and genetic subset were not statistically significant. There were no differences in outcome within each age category for any GBM variant, although the longest mean symptom-free survival was noted among patients aged 41-60 years with the p53 positive/EGFR negative variant. This study therefore indicates that at least four subsets of GBM exist, but despite different genotypes, the biologic behavior remains similar. Other genetic alterations therefore need to be investigated to identify prognostic makers.

In Germany about 400 children are diagnosed of having a brain tumour each year. About half of them are located in the supratentorial region. Despite the fact, that brain tumours are the most common solid tumour in childhood, they are very heterogeneous, regarding clinical symptoms, pathology, treatment and prognosis. Imaging studies play an important role for diagnosis and follow-up.

Because of its unpredictable clinical course, treatment strategies for low-grade (grade II) astrocytoma vary from "wait and see" to gross tumour resection followed by immediate radiotherapy. Clinical studies on grade II astrocytoma show that 5-year-survival ranges from 27% to 85% of patients with very few consistent prognostic variables besides the patient's age and the presence of neurological deficit. There is no universally recognised choice of therapy for patients with astrocytoma grade II, partly because of the shortcomings of histological classification systems. Routine microscopy tends to underestimate malignancy grading of astrocytomas and in most cases cannot distinguish between indolent and progressive subtypes. Recent studies suggest that proliferation and genetic markers can be used to identify subgroups of astrocytoma grade II with a rapid progressive clinical course. Therefore these markers should be included in ongoing and future clinical studies of patients with astrocytoma grade II.

Objective: The aim of this prospective study was to compare the diagnostic value of magnetic resonance imaging (MRI) and stereotactic biopsy in patients harboring WHO grade II gliomas., Methods: Stereotactic biopsy was performed in 62 adult patients with low-signal, nonenhancing, space-occupying lesions on T1 MR imaging between 1998 and 2001. The results of histological analysis were compared to the preoperative imaging diagnoses. Any adverse perioperative sequel was considered as morbidity. Applied treatment strategies are described., Results: Transient perioperative morbidity for the stereotactic approach was 4.8% (three patients), and there was no mortality or permanent morbidity. In four patients, neoplastic lesions could be excluded (gliosis: three patients, encephalitis: one), and WHO grade III gliomas were seen in five patients (14.8.% false positive rate of neurodiagnostic imaging). The diagnostic reliability of stereotactic biopsy was 96.8%. The following treatment strategies were initiated: microsurgery (17 patients), interstitial radiosurgery (12 patients), combination of microsurgery and interstitial radiosurgery (21 patients), external beam irradiation (six patients),and chemotherapy (two patients). Four patients were initially not treated., Conclusions: Diagnostic neuroimaging is not sufficient for the planning of rational treatment strategies in patients harboring WHO grade II gliomas. Frame-based stereotactic biopsy is a prerequisite for individualized treatment strategies.

Background: In the context of many implied but not rigorously stated histologic feature combinations, the World Health Organization (WHO) classification of astrocytic tumors specifies only the presence or absence of endothelial proliferation, necrosis, and mitosis to distinguish astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme., Methods: The authors examined the effects of these and other reliably recognized histologic features on survival in the Childhood Brain Tumor Consortium (CBTC) sample of 340 children with supratentorial astrocytic tumors., Results: Overall, the WHO criteria distinguished only two prognostically distinct classes of astrocytomas. When the specific combinations of the three features were unambiguously designated, three diagnostic categories resulted. These revised diagnostic categories are consistent with WHO guidelines and have significantly different survival distributions. However, neither the original WHO diagnoses nor the revised categories adequately separated these tumors prognostically, because histologic features other than those specified by WHO were significantly associated with improved or worsened survival., Conclusions: Classifications based on small numbers of specified histologic features may not be feasible because they inadequately separate childhood astrocytic tumors into prognostically homogeneous groups. Preferable classification techniques are those that simultaneously account for all reliably recognized histologic features., (Copyright 2000 American Cancer Society.)

Our objective in this study was to identify histologically homogenous classes of childhood supratentorial neuroglial tumors. Previously, we identified five quantitative histologic factors (differing linear combinations of 17 reliably recognized histologic features in neuroglial tumors). They account for much of the histologic variance in the 703 supratentorial tumors in the Childhood Brain Tumor Consortium (CBTC) database. In this study, we used the scores on the factors in cluster analyses and identified eight classes of neuroglial tumors. Each of these classes had significant differences in histology, allowing the separation of many of the conventional types of neuroglial tumors into two or more classes. For instance, fibrillary astrocytoma, pilocytic astrocytoma, subependymal giant cell astrocytoma, anaplastic astrocytoma, oligodendroglioma, and ependymoma were represented in two or more classes. Often these classes had statistically significant differences in survival distributions. For instance, the two classes of "anaplastic astrocytomas" have widely discrepant 5-year survival probabilities of 0.7 and 0.2. Use of the classes identified in this study ensures relatively homogeneous histologic subsets of tumors. We suggest that these classes will be useful for the selection of children for therapeutic clinical trials.

Classification and grading of astrocytic tumors has been the subject of several controversies and no universally accepted classification system is yet available. Nevertheless, acceptance of a common system is important for assessing prognosis as well as easy comparative evaluation and interpretation of the results of multi-center therapeutic trials. We report the results of a single center study on comparative survival evaluation along with assessment of inter-classification concordance in 102 cases of supratentorial astrocytic tumors in adults ((3) (3)16 years of age). Hematoxylin and eosin (H&E) stained slides of these 102 cases were reviewed independently by two pathologists and each case classified or graded according to four different classification systems viz. Kernohan, Daumas-Duport (SAM-A), TESTAST-268 and WHO. The histological grading was then correlated with the survival curves as estimated by the Kaplan-Meier method. The most important observation was that similar survival curves were obtained for any one grade of tumor by all the four classification systems. Fifty three of the 102 cases (51.9%) showed absolute grading concordance using all 4 classifications with maximum concordant cases belonging to grades 2 and 4. Intra-classification grade-wise survival analysis revealed a statistically significant difference between grade 2 and grades 3 or 4, but no difference between grades 3 and 4 in any of the classification systems. It is apparent from the results of this study that if specified criteria related to any of the classification systems is rigorously adhered to, it will produce comparable results. Hence, preferential adoption of any one classification system in practice will be guided by the relative ease of histologic feature value evaluation with maximum possible objectivity and reproducibility. We recommend the Daumas-Duport (SAM-A) system since it appears to be the simplest, most objectivized for practical application and highly reproducible with relative ease.

The histologic heterogeneity of childhood supratentorial neuroglial tumors, when quantified, identifies relatively homogeneous subgroups for prognostic purposes and for assignment in clinical trials. Our sample consisted of supratentorial tumors in the Childhood Brain Tumor Consortium. The data consist of reliably identified histologic features and demographic, clinical, operative, and survival information. Factor analysis was used to identify uncorrelated "factors," each represented by a different combination of histologic features in 703 tumors. The defining histologic features were used to label each factor. The heterogeneity of each tumor was summarized using the factor scores for each factor. We compared the survival estimates of subgroups of tumors within common diagnostic classes. We identified five uncorrelated quantitative factors that accounted for much of the histologic variation. Our factor labels were Jumbo, Fibrillary, Proliferative, Spongy, an Oligodendroglial. Two thirds of tumors had high scores on two or more factors, indicating a high degree of heterogeneity among these tumors. Eighty-four percent of supratentorial tumors were accounted for by 19 nonoverlapping relatively homogeneous histologic groups. The five quantitative factors complement standard qualitative taxonomies by summarizing more completely the histologic feature aspects of a tumor than by diagnosis alone and quantify the histologic heterogeneity of individual tumors. Histologically homogeneous groups of tumors are essential for clinical trials, biologic research, and prognostic models.

The aim of this study was to obtain an MRI severity-related classification of diffuse astrocytic tumours able to integrate the histological data in the grading of such tumours. We studied presurgical MR images of 91 patients with a histological diagnosis of astrocytoma, anaplastic astrocytoma and glioblastoma. A score ranging from 1 to 3 was assigned by two independent readers to each of the following MR features: oedema, mass effect, contrast enhancement, borders, signal homogeneity, necrosis, haemorrhage and flow void. Statistical analysis showed significant differences in the mean MRI scores between the three histological grades. Contrast enhancement was found to be the best predictor of the histological grade followed by necrosis, signal homogeneity and border scores. This classification represents a simple and reproducible means of carefully evaluating some macroscopic characteristics of these tumours. It could be used to integrate histological data especially in cases in which tissue sampling defects may affect the validity of this examination.

Although conventional proton magnetic resonance imaging has increased our ability to detect brain tumors, it has not enhanced to nearly the same degree our ability to diagnose tumor type. Proton magnetic resonance spectroscopy is a safe, noninvasive means of performing biochemical analysis in vivo. Using this technique, we characterized and classified tissue from normal brains, as well as tissue from the five most common types of adult supratentorial brain tumors. These six tissue types differed in their pattern across the six metabolites measured. 'Leaving-one-out' linear discriminant analyses based on these resonance profiles correctly classified 104 of 105 spectra, and, whereas conventional preoperative clinical diagnosis misclassified 20 of 91 tumors, the linear discriminant analysis approach missed only 1. Thus, we have found that a pattern-recognition analysis of the biochemical information obtained from proton magnetic resonance spectroscopy can enable accurate, noninvasive diagnosis of the most prevalent types of supratentorial brain tumors.

Pediatric supratentorial tumors represent about 50% of all intracranial neoplasms. The most frequent tumors of the cerebral hemispheres are gliomas that arise from astrocytes, oligodendrocytes or ependymal cells. The incidence of the different histologic types is difficult to be established as many tumors have a mixed cellularity, thus classification is based on the prevalent oncotype or the most malignant component. Choroid plexus papillomas and ependymomas are the most common ventricular neoplasms. However, subependymal giant cell astrocytomas, subependymomas, teratomas are also observed. The parasellar region is a frequent site of pediatric tumors as craniopharyngiomas, optic pathway gliomas and germinomas. Pinealomas are less common. Signs and symptoms related to increased intracranial pressure are often reported and vary according to the patient's age. Macrocrania and a bulging fontanel can be observed in infants and toddlers, whereas headache, papilledema and vomiting are present in the older children. A tumor hindering CSF circulation may cause hydrocephalus. Focal signs include epilepsy and neurological deficits characteristic of tumor location. Total removal of the tumor is the ideal surgical therapy. When eloquent areas are involved, partial exeresis is indicated. Radiotherapy is usually administered to malignant tumors even if in younger children its use in markedly limited by the possible severe side-effects on the developing brain. Chemotherapy seems effective in some brain neoplasms, however most suitable drugs and dose need to be established. It may represent an alternative to radiotherapy in children less than three years of age.

We compared quantitative analysis of conventional MR and magnetization transfer (MT) images with visual morphologic assessment of standard images in the classification of gliomas. Thirty-two patients with gliomas were imaged preoperatively. Relative signal intensities on T2- and T1-weighted images, Gd-enhancement, signal heterogeneity on T2-weighted and Gd-enhanced T1-weighted images and MT ratios were measured. In 16 astrocytomas, the MT ratios were correlated with the volume fraction of tumor cell nuclei in histological sections. Among the conventional sequences T2-weighted images were most accurate for quantitative classification; signal heterogeneity was more accurate than relative signal intensity. MT ratios were superior to quantitative analysis of conventional images and equal to visual morphologic evaluation in discriminating between low-grade and high-grade gliomas and correlated with the volume fraction of nuclei in the tumor tissue (r = 0.71, p < .01). The results indicate that quantitative analysis is generally of minor value in the grading of gliomas. In spite of sensitivity to tissue changes associated with malignancy MT imaging cannot significantly improve MR classification of gliomas.

To evaluate the usefulness of an MRI score for identifying tumour tissue characteristics, 41 histologically verified supratentorial astrocytic gliomas, including 13 low-grade astrocytomas (LGA) 14 anaplastic astrocytomas (AA) and 14 glioblastoma multiformes (GBM), were examined with a 0.5T superconductive MR imager. Nine MRI criteria were used: heterogeneity (HET), cyst formation or necrosis (CN), haemorrhage (HEM), crossing the midline (CM), oedema or mass effect (EM), border definition (BD), flow void (FV), degree (CE-D) and heterogeneity (CE-HET) of contrast enhancement; Gd-enhanced T1-weighted images were obtained in 32 cases (10 LGA, 10 AA, and 12 GBM). Each of the criteria was scored and analysed statistically. The mean values of LGA, AA and GBM were 0.45 +/- 0.31, 1.18 +/- 0.20, and 1.47 +/- 0.22, respectively. The MRI score increased with the pathological grades (P < 0.01-0.001). LGA had significantly lower values than AA in five (HET, CN, EM, BD, CE-D) of the nine criteria (55.6%) and lower values than GBM in all except HEM (88.9%). Three criteria (33.3%): HET, CN, and FV were significantly higher in GBM than AA. CE-D, HET, EM, CN, and CE-HET proved to be related to the pathological grade by a multiple regression analysis (P < 0.001).

The findings at magnetic resonance (MR) imaging in a group of 36 pathologically verified supratentorial gliomas were analyzed and compared with the biopsy diagnoses (a) to determine whether MR imaging could be used to classify astrocytic-series tumors into a three-tiered system of low-grade astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme; and (b) to evaluate MR imaging features that may aid in this classification. The MR characteristics evaluated were crossing of the midline, edema, tumor signal heterogeneity, hemorrhage, border definition, cyst formation or necrosis, and mass effect. The statistically significant MR characteristics (positive predictors) were mass effect (P = .0000) and cyst formation or necrosis (P = .0512). The MR accuracy rate approached that of neuropathologic diagnosis, which is subject to sampling errors. MR imaging may serve as an adjunct in case management when the clinical course and MR findings appear to be at odds with the neuropathologic diagnosis.

Brain tumors represent 40% to 50% of all solid tumors in children under 18 years of age, with an average incidence of 2 to 5 cases per 100,000/annum. These tumors are gliomas in 60% to 70% of cases. The most common location is infratentorial (60% of cases), with cerebellar astrocytomas, medulloblastomas and brain stem gliomas occurring in equal measure (20%). Astrocytomas are the predominant form (25%) in the supratentorial compartment. This review analyses clinical symptoms and instrumental procedures for the diagnosis of various types of brain tumor, together with recommendations for their management based on controlled clinical trials.