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A 41-year-old man presented to us with left arm and leg weakness and mild word finding difficulties. His preoperative magnetic resonance imaging (MRI) demonstrated abnormal T1 and T2 signal changes in the right temporal lobe and basal ganglia, indicative of possible glioma. An awake craniotomy for right temporal lobectomy was performed and the tumor was resected. Full pathologic workup later revealed the patient had two distinct tumors occurring simultaneously, anaplastic astrocytoma and astroblastoma. We review the literature regarding the treatment of anaplastic astrocytoma and astroblastoma and discuss their co-occurrence.

Astroblastoma is an uncommon pediatric neuroepithelial tumor. The prognosis and appropriate treatment of astroblastoma were not well understood. Previous reports suggested the best treatment for astroblastoma is surgical total resection. The authors report a case of pediatric astroblastoma that underwent gross total resection with the use of fluorescent guidance by 5-aminolevulinic acid (5-ALA). A 13-year-old girl presented with the tumor that was well-circumscribed cystic and solid mass with marked gadolinium enhancement in the right occipital lobe. At surgery, fluorescence of the tumor was clearly distinctive from the normal cerebral tissue. All fluorescent tissue including residual cyst wall was removed. Postoperative MRI showed gross total resection of the tumor. No serious side effect or complications occurred. The histopathologic diagnosis was suggestive of astroblastoma. The patients had no evidence of recurrence of tumor without adjuvant radiotherapy during the last 1 year of follow-up time. 5-ALA is useful to achieve gross total resection including cystic lesion of pediatric astroblastoma. A larger prospective study is warranted to establish the use of 5-ALA in pediatric brain tumor.

Objective Pediatric glial tumors comprise wide range pathologies which may mimic histomorphological features of each other's but generally have very diverse disease course. WHO Classification of Tumors of Central Nervous System (2016 and 2021) points to the necessity of investigating several molecular alterations for integrated pathological diagnosis of childhood CNS tumors. This makes customized next-generation sequencing (NGS) a powerful tool for the diagnosis of childhood CNS tumors. Methodology Acibadem Molecular Pathology Brain Tumor NGS Panel was designed according to targeted deep RNA and DNA sequencing. RNA and DNA were isolated from paraffin blocks containing more than 50% tumor in 45 cases with childhood CNS tumors. Miniseq Sequencing System, Illumina and Archer Analysis Ver 6.0.3.2 platforms were used. Fusions (translocations), mutations, and DNA copy number changes in 81 genes were screened for the most common molecular alterations in CNS tumors. Results Fourty-five childhood CNS tumors were evaluated with NGS results. Among these there were 19 pilocytic astrocytomas, 1 case of high grade astrocytoma with piloid features, 4 diffuse leptomeningeal glioneuronal tumors, 1 pleomorphic xanthoastrocytoma, 4 pediatric diffuse glial tumors, 1 infantile hemispheric astrocytoma, 1 astroblastoma, 12 diffuse midline glioma. Sixteen of these tumors were able to be diagnosed based on these molecular findings. Thirty-four cases received targeted therapies. Conclusion The customized NGS panel, as a single molecular workflow is very helpful and supportive in diagnosis for CNS childhood tumors. Since the number of driver mutations are few in childhood tumors, detection of the driver molecular alteration is guiding the medical treatment startegy in terms of targeted regimens.

Rationale Astroblastoma is a rare tumor of the central nervous system with uncertain biological behavior and origin. Its histopathological features have been well established, while, to our knowledge, astroblastoma with oligodendroglial-like cells have not been reported. Patient concerns A 15-year-old girl presented with nausea, vomiting, headache, and visual disturbance. Diagnosis Magnetic resonance imaging revealed a large neoplasm in the left temporal. Histologically, the tumor showed solid and pseudopapillary structure. Immunohistochemical staining showed that the tumor cells were positive for glial fibrillary acidic protein and vimentin. The oligodendroglial-like cells were positive for glial fibrillary acidic protein, vimentin, and oligodendrocyte transcription factor 2. The antigen KI67 labeling index was about 4%. Sequencing for isocitrate dehydrogenase (IDH) 1 codon 132 and IDH2 codon 172 gene mutations showed negative results. Furthermore, fluorescent analysis revealed neither 1p nor 19q deletion in the lesion. Based on these findings, the girl was finally diagnosed as astroblastoma. Interventions A craniotomy with total excision of the tumor was performed. Outcomes The follow-up time was 1 year, no evidence of disease recurrence was found in magnetic resonance imaging. Lessons Cerebral astroblastoma with oligodendroglial-like cells is a clinically rare tumor of central nervous system. Clear distinction and diagnosis are critical.

Astroblastoma is a rare and controversial glioma with variable clinical behavior. The diagnosis currently rests on histologic findings of a circumscribed glioma with astroblastomatous pseudorosettes and vascular hyalinization. Immunohistochemical studies have suggested different oncogenic drivers, such as BRAF p.V600E, but very few cases have been studied using genome-wide methodologies. Recent genomic profiling identified a subset of CNS embryonal tumors with astroblastoma-like morphology that harbored MN1 gene fusions, termed "CNS high-grade neuroepithelial tumors with MN1 alteration" (CNS-HGNET-MN1). To further characterize the genetic alterations that drive astroblastomas, we performed targeted next-generation sequencing (NGS) of 500 cancer-associated genes in a series of eight cases. We correlated these findings with break-apart fluorescence in situ hybridization (FISH) analysis of the MN1 locus and genome-wide DNA methylation profiling. Four cases showed MN1 alteration by FISH, including two pediatric cases that lacked other pathogenic alterations, and two adult cases that harbored other cancer-associated gene mutations or copy number alterations (eg, CDKN2A/B homozygous deletion, TP53, ATM and TERT promoter mutations). Three of these cases grouped with the CNS-HGNET-MN1 entity by methylation profiling. Two of four MN1 intact cases by FISH showed genetic features of either anaplastic pleomorphic xanthoastrocytoma (BRAF p.V600E mutation, CDKN2A/B homozygous deletion and TERT promoter mutation) or IDH-wildtype glioblastoma (trisomy 7, monosomy 10, CDK4 amplification and TP53, NRAS and TERT promoter mutations) and these cases had an aggressive clinical course. Two clinically indolent cases remained unclassifiable despite multimodal molecular analysis. We conclude that astroblastoma histology is not specific for any entity including CNS-HGNET-MN1, and that additional genetic characterization should be considered for astroblastomas, as a number of these tumors likely contain a methylation profile or genetic alterations that suggest classification as other tumor entities. Our heterogeneous molecular findings help to explain the clinical unpredictability of astroblastoma.

A recurrent glycine-to-arginine/valine alteration at codon 34 (G34R/V) within H3F3A, a gene that encodes the replication-independent histone variant H3.3, reportedly occurs exclusively in pediatric glioblastomas. However, the clinicopathological and biological significances of this mutation have not been completely elucidated; especially, no such data exist for tumor samples from Japanese patients. We analyzed 411 consecutive glioma cases representing patients of all ages. Our results demonstrated that 14 patients (3.4%) harbored H3F3A mutations, of which four had G34R mutations and 10 had K27M mutations. G34R-mutant tumors were located in the parietal region in two patients and the basal ganglia in one patient. One patient showed multi-lobular extension similar to the pattern observed in gliomatosis cerebri. Regarding neuroradiological features, intratumoral calcification was evident in two cases and all cases showed no or scarce contrast enhancement on MRI. Histopathologically, the four G34R-mutant cases included three glioblastomas and one astroblastoma. We have also investigated alterations in histone methylation including H3K27me3, H3K9me3, and H3K4me3 in G34R-mutant samples by immunohistochemistry. These results indicate that G34R-mutant tumors are likely to show extensive infiltration and alterations in global histone trimethylation might also play an important role in G34R mutant tumors.

The purpose of this study is to investigate the incidence of cystic malacia in long-term survivors of pediatric brain tumors treated with high-dose cranial irradiation. Between 1997 and 2015, we treated 41 pediatric patients (26 males, 15 females; age ranging from 3.3 to 15.7 years, median 9-year-old) of pediatric brain tumors [17 medulloblastomas, 7 primitive neuroectodermal tumors (PNET), 3 pineoblastomas, 6 non-germinomatous germ cell tumors (NGGCT), 8 gliomas (including 4 ependymomas, 1 anaplastic astrocytoma, 1 oligodendroglioma, 1 pilocytic astrocytoma, 1 astroblastoma)] with high-dose craniospinal irradiation. Follow-up ranged from 14.0 to 189.2 months (median 86.0 months, mean 81.5 months), the irradiation dose to the whole neural axis ranged from 18 to 41.4 Gy, and the total local dose from 43.2 to 60.4 Gy. All patients underwent follow-up magnetic resonance imaging (MRI) studies at least once a year. Diagnosis of cystic malacia was based solely on MRI findings. Of the 41 patients, 31 were censored during their follow-up due to recurrence of the primary disease (n = 5), detection of secondary leukemia after development of cystic malacia (n = 1), or the absence of cystic malacia on the last follow-up MRI study (n = 25). We also evaluated the development of post-irradiation cavernous angioma and white matter changes. Following irradiation treatment, 11 patients developed 19 cystic malacia during a median course of 30.8 months (range 14.9 to 59.3 months). The site of predilection for cystic malacia was white matter around trigone of lateral ventricles with an incidence of 47.4% (9 of 19 lesions, 7 in 11 patients). Patients with supratentorial tumors developed cystic malacia statistically earlier than the patients with infratentorial tumors (P = 0.0178, log-rank test). Among the same patient group, incidence of post-irradiation cavernous angioma increased progressively, while the incidence of post-irradiation cystic malacia did not increase after 5 years. White matter degeneration developed earlier than cystic malacia or cavernous angioma, and these three clinical entities developed mutually exclusive of each other. We attribute the higher incidence of post-irradiation cystic malacia, in our long-term follow-up study, to the cranial irradiation for pediatric brain tumors, particularly supratentorial brain tumors, and recommend a regular, long-term follow-up of brain tumor patients treated with cranial irradiation.

Astroblastomas are uncommon tumors of uncertain histogenesis. Recently tanycyte is postulated to be the cell of origin. These occur predominantly in the cerebral hemisphere of young adults and children. Astroblastoma constitutes approximately 0.45 to 2.8% of all neuroglial tumors. We are reporting a case of 28-year-old woman who presented with headache and double vision. Magnetic resonance imaging (MRI) of the brain revealed well-demarcated, ring-enhancing solid cystic mass in right temporoparietal lobe with significant mass effect. The patient underwent gross total resection of the lesion through right temporoparietal craniotomy. The histopathologic diagnosis was suggestive of astroblastoma. She was advised for postoperative radiotherapy, but she lost to follow-up and again presented 1 year later with recurrent tumor in the same location along with another lesion in infratentorial location. She was reoperated and gross total excision of supra- and infratentorial tumor was done. She also received radiotherapy. We are reporting this uncommon case of astroblastoma and also reviewing the existing literature.

Cell lines established from tumors are the most commonly used models in cancer research, and their use in recent years has enabled a greater understanding of the biology of cancer and the means to develop effective treatment strategies. Astroblastomas are uncommon neuroepithelial tumors of glial origin, predominantly affecting young people, mainly teenagers and children, predominantly females. To date, only a single study has reported that astroblastomas contain a large number of neural stem-like cells, which had only a partial proliferation capacity and differentiation. Our objective was to establish an astroblastoma cell line to investigate the presence of astroblastic cells and cancer stem-like cells. The migratory and invasion abilities of the cells were quantified with invasion and migration assays and compared to a glioblastoma cell line. The presence of stem cells was detected with surface-marker analysis by using flow cytometry, and measuring the differentiation ability with a differentiation assay and the self-renewal capacity with a sphere-forming assay. These characteristics may determine whether this novel cell line is a model for astroblastomas that may have stem-cell characteristics. With this novel cell line, scientists can investigate the molecular pathways underlying astroblastomas and develop new therapeutic strategies for patients with these tumors.

Astroblastomas are rare, potentially curable primary brain tumors which can be difficult to diagnose. We present the case of astroblastoma in a 73-year-old male, an atypical age for this tumor, more classically found in pediatric and young adult populations. Through our case and review of the literature, we note that this tumor is frequently reported in adult populations and the presentation of this tumor in the elderly is well described. This tumor is an important consideration in the differential diagnosis when managing both pediatric and adult patients of any age who present with the imaging findings characteristic of this rare tumor.

Astroblastoma (AB) is a rare CNS tumor demonstrating abundant astroblastomatous pseudorosettes. Its molecular features have not been comprehensively studied and its status as a tumor entity is controversial. We analyzed a cohort of 27 histologically-defined ABs using DNA methylation profiling, copy number analysis, FISH and site-directed sequencing. Most cases demonstrated mutually exclusive MN1 rearrangements (n = 10) or BRAFV600E mutations (n = 7). Two additional cases harbored RELA rearrangements. Other cases lacked these specific genetic alterations (n = 8). By DNA methylation profiling, tumors with MN1 or RELA rearrangement clustered with high-grade neuroepithelial tumor with MN1 alteration (HGNET-MN1) and RELA-fusion ependymoma, respectively. In contrast, BRAFV600E-mutant tumors grouped with pleomorphic xanthoastrocytoma (PXA). Six additional tumors clustered with either supratentorial pilocytic astrocytoma and ganglioglioma (LGG-PA/GG-ST), normal or reactive cerebrum, or with no defined DNA methylation class. While certain histologic features favored one genetic group over another, no group could be reliably distinguished by histopathology alone. Survival analysis between genetic AB subtypes was limited by sample size, but showed that MN1-rearranged AB tumors were characterized by better overall survival compared to other genetic subtypes, in fact, significantly better than BRAFV600E-mutant tumors (P = 0.013). Our data confirm that histologically-defined ABs are molecularly heterogeneous and do not represent a single entity. They rather encompass several low- to higher-grade glial tumors including neuroepithelial tumors with MN1 rearrangement, PXA-like tumors, RELA ependymomas, and possibly yet uncharacterized lesions. Genetic subtyping of tumors exhibiting AB histology, particularly determination of MN1 and BRAFV600E status, is necessary for important prognostic and possible treatment implications. Electronic supplementary material The online version of this article (10.1186/s40478-019-0689-3) contains supplementary material, which is available to authorized users.

Astroblastoma is a rare tumor of the central nervous system (CNS) with uncertain clinical behavior. Recently, DNA methylation profiling has been shown to provide a highly robust and reproducible approach for the classification of all CNS tumors across different age groups. By using DNA methylation profiling, a subset of CNS high-grade tumors with astroblastoma-like morphology characterized by the meningioma 1 gene (MN1) rearrangements, has been identified; they were termed "CNS high-grade neuroepithelial tumors with MN1 alteration" (CNS-HGNET-MN1). Here, we describe a case of CNS-HGNET-MN1 diagnosed by DNA methylation profiling, using Illumina Infinium HumanMethylationEPIC BeadChip (EPIC), that offers the opportunity to conduct a brief literature review. The patient presented with an episode of partial seizures involving the right hemisoma. A gross total resection was performed. No other treatment was proposed in light of the histological and molecular findings. After 21 months, the patient is disease-free in good clinical conditions. Also in view of this case, we recommend DNA-methylation profiling as an important tool for diagnosis and more effective patient stratification and management.

Background: Astroblastoma is rare neuroglial intracranial tumor most commonly occurring in the first three decades of life. Case report: A 5 year old female child presented with intermittent headache, diplopia and recurrent seizures over a period of approximately 4 months. Her neurological examination revealed 6th nerve palsy and papilledema. Both CT and MRI revealed a well defined enhancing solid-cystic mass in the left fronto-parietal cerebral cortex with mass effect suggestive of primitive neuroectodermal tumor. She underwent gross total resection of the lesion through craniotomy. Histopathology along with immunohistochemistry was surprisingly suggestive of astroblastoma. Conclusion: Astroblastomas are very rare and often misdiagnosed.

Brain tumors harbor various BRAF alterations, the vast majority of which are the BRAF kinase-activating V600E mutation. BRAF mutations are most frequently detected in certain subtypes of low-grade glioma, such as pilocytic astrocytoma (PA), pleomorphic xanthoastrocytoma (PXA), ganglioglioma (GG) and dysembryoplastic neuroepithelial tumor (DNT). However, it is unclear whether gliomas harboring BRAF mutations can be invariably regarded as these glioma subtypes or their derivatives. To address this question, we analyzed 274 gliomas in our institutional case series. We performed high-resolution melting analyses and subsequent direct Sanger sequencing on DNA isolated from snap-frozen tumor tissues. As expected, BRAF mutations were detected in the aforementioned low-grade gliomas: in 4/27 PAs, 2/3 PXAs, 4/8 GGs, and 1/6 DNTs. In addition to these gliomas, 1/2 astroblastomas (ABs) and 2/122 glioblastomas (GBs) harbored BRAF mutations. Pathological investigation of the two GBs revealed that one was a GB displaying epithelial features that presumably arose from a precedent GG, whereas the other GB, which harbored a rare G596 A mutation, showed marked epithelial features, including astroblastic rosettes. Our results indicate that in addition to being present in established BRAF-associated gliomas, BRAF mutations might be associated with epithelial features in high-grade gliomas, including sheet-like arrangement of polygonal tumor cells with a plump cytoplasm and astroblastic rosettes, and thus could potentially serve as a genetic marker for these features.

Astroblastomas are rare primary brain tumors, diagnosed based on histologic features. Not currently assigned a WHO grade, they typically display indolent behavior, with occasional variants taking a more aggressive course. We characterized the immunohistochemical characteristics, copy number (high-resolution array comparative genomic hybridization, OncoCopy) and mutational profile (targeted next-generation exome sequencing, OncoPanel) of a cohort of seven biopsies from four patients to identify recurrent genomic events that may help distinguish astroblastomas from other more common high-grade gliomas. We found that tumor histology was variable across patients and between primary and recurrent tumor samples. No common molecular features were identified among the four tumors. Mutations commonly observed in astrocytic tumors ( IDH1/2 , TP53 , ATRX , and PTEN ) or ependymoma were not identified. However one case with rapid clinical progression displayed mutations more commonly associated with GBM ( NF1 N1054H/K63 *, PIK3CA R38H and ERG A403T ). Conversely, another case, originally classified as glioblastoma with nine-year survival before recurrence, lacked a GBM mutational profile. Other mutations frequently seen in lower grade gliomas ( BCOR, BCORL1, ERBB3, MYB, ATM ) were also present in several tumors. Copy number changes were variable across tumors. Our findings indicate that astroblastomas have variable growth patterns and morphologic features, posing significant challenges to accurate classification in the absence of diagnostically specific copy number alterations and molecular features. Their histopathologic overlap with glioblastoma will likely confound the observation of long-term GBM "survivors". Further genomic profiling is needed to determine whether these tumors represent a distinct entity and to guide management strategies.

Astroblastoma is a rare tumor of uncertain origin most commonly presenting in the cerebrum of children and young adults. The literature contains only case reports and small series regarding its radiologic features. This systematic review is the largest study of imaging findings of astroblastoma to date and serves to identify features that might differentiate it from other neoplasms. This study describes the imaging features of astroblastoma based on a systematic review of the literature and two new cases. We conducted a PubMed and Google Scholar database search that identified 59 publications containing 125 cases of pathology-confirmed astroblastoma, and we also added two new cases from our own institution. Data collected include patient age, gender, tumor location, morphology, calcifications and calvarial changes. We recorded findings on CT, MRI, diffusion-weighted imaging (DWI), MR spectroscopy, positron emission tomography (PET) and catheter angiography. Age at diagnosis ranged 0–70 years (mean 18 years; median 14 years). Female-to-male ratio was 8:1. Of 127 cases, 66 reported CT, 78 reported MRI and 47 reported both findings. Not all authors reported all features, but the tumor features reported included supratentorial in 96% (122/127), superficial in 72% (48/67), well-demarcated in 96% (79/82), mixed cystic–solid in 93% (79/85), and enhancing in 99% (78/79). On CT, 84% (26/31) of astroblastomas were hyperattenuated, 73% (27/37) had calcifications and 7 cases reported adjacent calvarial erosion. Astroblastomas were hypointense on T1-W in 58% (26/45) and on T2-W in 50% (23/46) of MRI sequences. Peritumoral edema was present in 80% (40/50) of cases but was typically described as slight. Six cases included DWI findings, with 100% showing restricted diffusion. On MR spectroscopy, 100% (5/5) showed nonspecific tumor spectra with elevated choline and decreased N-acetylaspartate (NAA). PET revealed nonspecific reduced uptake of [F-18] 2-fluoro-2-deoxyglucose (18F-FDG) and increased uptake of [11C]-Methionine in 100% (3/3) of cases. Catheter angiography findings (n=12) were variable, including hypervascularity in 67%, arteriovenous shunting in 33% and avascular areas in 25%. Astroblastomas occur most often in adolescent girls. Imaging often shows a supratentorial, superficial, well-defined, cystic–solid enhancing mass. On CT, most are hyperattenuated, have calcifications, and may remodel adjacent bone if superficial. MRI characteristically reveals a hypointense mass on T1-W and T2-W sequences with restricted diffusion. MR spectroscopy, PET and catheter angiography findings are nonspecific.

El Astroblastoma es una neoplasia maligna de células gliales derivada de una célula primitiva, el astroblasto, precursor del astrocito. Situado de forma intermedia entre el glioblastoma y astrocitoma anaplásico, por lo cual su principio estructural es una imagen microscópica sin patrón anatomoclínico definido. Es una neoplasia poco frecuente, de crecimiento rápido e infiltrante, su incidencia es totalmente desconocida y su diagnóstico en ciertos casos es complejo. Predomina en niños, adultos jóvenes y sexo femenino. Suelen aparecer en los hemisferios cerebrales como lesiones ocupantes de espacio (LOE), bien definidos, presentando a menudo un componente quístico. Su principal característica histopatológica es la presencia de pseudorosetas perivasculares. Las manifestaciones clínicas más frecuentes son: cefaleas y crisis comiciales tardías. Presentamos el caso de escolar masculino de 8 años de edad, que ingresó al Hospital Universitario de Los Andes por presentar cefalea constante de tipo opresiva de fuerte intensidad de 2 meses de aparición, el cual aliviaba con analgésicos comunes (Paracetamol), concomitante dolor punzante en la región orbitaria derecha irradiado a hemicráneo ipsilateral, visión borrosa y vómitos. Al examen físico presentaba disminución de la agudeza visual de globo ocular derecho, sin otros signos relevantes. Se realizó TAC y RMN donde se visualizó LOE de ubicación temporo-parietal derecha con compresión del nervio óptico del mismo lado: por tal motivo se procedió a realizar craneotomía más exéresis del LOE temporo-parietal. El estudio anatomopatológico reportó una neoplasia de células gliales: astroblastoma.

Astroblastoma is a rare tumor of glial origin with characteristics of both astrocytoma and ependymoma. It is usually seen in children and young adults, and is peripherally located, well circumscribed, of solid-cystic composition and with heterogeneous contrast enhancement. Histopathology reveals perivascular pseudorosette formation and thick hyalinised vessels. Hemorrhage in astroblastoma is unusual and rarely described in literature. We report two patients with astroblastoma who presented with hemorrhage and discuss the natural history, radiological findings, pathophysiology of hemorrhage and histopathological characteristics. We emphasize the importance of early suspicion in peripherally located lesions with bleeding.

Item does not contain fulltext Primitive neuroectodermal tumors of the central nervous system (CNS-PNETs) are highly aggressive, poorly differentiated embryonal tumors occurring predominantly in young children but also affecting adolescents and adults. Herein, we demonstrate that a significant proportion of institutionally diagnosed CNS-PNETs display molecular profiles indistinguishable from those of various other well-defined CNS tumor entities, facilitating diagnosis and appropriate therapy for patients with these tumors. From the remaining fraction of CNS-PNETs, we identify four new CNS tumor entities, each associated with a recurrent genetic alteration and distinct histopathological and clinical features. These new molecular entities, designated "CNS neuroblastoma with FOXR2 activation (CNS NB-FOXR2)," "CNS Ewing sarcoma family tumor with CIC alteration (CNS EFT-CIC)," "CNS high-grade neuroepithelial tumor with MN1 alteration (CNS HGNET-MN1)," and "CNS high-grade neuroepithelial tumor with BCOR alteration (CNS HGNET-BCOR)," will enable meaningful clinical trials and the development of therapeutic strategies for patients affected by poorly differentiated CNS tumors.

The most recurrent fusion of CNS high-grade neuroepithelial tumor with MN1alteration(HGNET-MN1) is MN1- BEN Domain Containing 2(BEND2) fusion. Recently, there was a report of a 3-month-old boy with spinal astroblastoma, classified as CNS HGNET-MN1 by DKFZ methylation classification but positive for EWSR1-BEND2 fusion(Yamasaki, 2019). Here, we report a 36-year old man with a spinal cord astroblastoma with EWSR1 alternation. The patient presented with back pain, gait disorder and dysesthesia in lower extremities and trunk was referred to our hospital. MRI showed intramedullary tumor in Th3-5 level, displaying low-intensity on T1 weighted image, high-intensity on T2 weighted image, and homogeneous gadolinium enhancement. Partial removal was performed with the laminectomy. The tumor extended to extramedullary and its boundary was unclear. Histological examinations showed the epithelium-like tumor cells with eosinophilic cytoplasm with high cellularity palisade, intracellar fibrosis, and mitosis. Immunohistochemical staining showed positive for Olig2, GFAP, EMA, SSTR2, S-100, but negative for p53, PgRAE1/AE3. The tumor was diagnosed as astroblastoma, and was classified as HGNET-MN1 by the DKFZ methylation classifier. However, the MN1 alternation was not detected by fluorescence in situ hybridization, instead EWSR1 and BEND2 alternations which suggested EWSR1-BEND2 fusion were detected. After radiation therapy of 54Gy/30fr with bevacizumab and temozolomide, the residual tumor reduced the size and his symptoms improved. This case provides evidence that EWSR1-BEND2 fusion is recurrent in HGNET-MN1 and, as previously reported, suggests the importance of BEND2 in this entity. These two cases suggested that it may be the BEND2 alteration that biologically defines the HGNET-MN1 subclass rather than MN1.

INTRODUCTION Astroblastoma is a rare, mostly supratentorial glial tumor, occurring predominantly in children and young adults. However, treatment strategies have not yet been established for this rare disease. CASE PRESENTATION A 6-year-old male presented with headache and nausea. CT and MR imaging revealed a left frontal mass lesion with slight edema and macrocalcifications. Gross tumor resection was performed. Histological examination found neoplastic cells with astroblastic characteristics, and a striking perivascular array of pseudorosettes. The final diagnosis was high-grade astroblastoma. MR imaging 13 months after surgery suggested local recurrence and enlargement was found 3 months later. Stereotactic radiotherapy (SRT) was performed. MR imaging after SRT showed enhanced cyst formation around the tumor bed, suggesting tumor recurrence. However, 11C-methionine PET revealed radiation necrosis. The last follow-up MR imaging 15 months after SRT showed no further recurrence. CONCLUSION Astroblastoma is rare, so no optimal management is known. SRT may be effective to treat recurrent astroblastomas. 11C-methionine PET/CT is useful for the differentiation from radiation necrosis.

Recurrent mutations in H3F3A that encodes the histone 3 variant H3.3, lead to amino acid substitutions including K27M and G34R/V-which are observed in high-grade gliomas (HGGs) of children and young adults. Previous studies have focused on gliomas with K27M mutation, whereas gliomas with G34R/V mutation have received little attention. Herein, we report three rare cases of glioblastoma (GBM) with H3.3 G34 mutation arising from a cerebral hemisphere in two children and one young adult. All three cases showed microscopic characteristics of central nervous system primitive neuroectodermal tumor (CNS-PNET, called CNS embryonal tumors in WHO 2016 Revised 4th Edition) and presented H3.3 G34 mutation. H3.3 G34-mutant brain tumors were formerly a group of histopathologically distinct neoplasms, involved in GBM, CNS-PNET, and astroblastoma. However, recent studies have demonstrated that different CNS tumors with H3.3 G34 mutation display coherent epigenetic signatures, implying a single biological origin. Correspondingly, our three cases showed high consistency in tumor location, histological morphology, and molecular phenotype. Their immunophenotypes are similar to astrocytoma, with ATRX loss and TP53 mutation. Therefore it suggests that these H3.3 G34-mutant brain tumors may be a rare entity of HGG.

Angiocentric glioma (AG) is a relatively uncommon clinico-pathological entity that presents in childhood. Angiocentric glioma displays various histopathological features which resemble cortical ependymoma, astroblastoma, and pilomyxoid astrocytoma and schwannoma. The astrocytes in angiocentric glioma appear peculiarly elongated, bipolar in shape, and characteristically arranged around blood vessels. They resemble radial glia and tanycytes morphologically. Unlike ependymomas, AG is a diffusely infiltrating lesion and perivascular processes are often much thicker than those in classic ependymomas. AG usually present clinically as seizures, often as medically intractable epilepsy. In the indexed case, apart from unusual presentation with features of raised intra-cranial tension, an unusual histological picture of a more cellular oligodendroglioma like component was also seen. The appropriate diagnosis is critical as AG is usually slowly growing and treatable by surgical excision alone.

Background Astroblastoma is a controversial and an extremely rare central nervous system neoplasm. Although its histogenesis has been clarified recently, controversies exist regarding its cellular origin and validity as a distinct entity. Because of its extreme rarity and because its common features are shared with other glial neoplasms, this tumor is prone to misdiagnosis and remains challenging not only in terms of diagnosis and classification but also in the subsequent management. This case report describes a new case of astroblastoma. It discusses clinical, radiologic, pathological, and therapeutic features and differential diagnosis of this rare neoplasm, with a review of the recent literature. Case presentation We report the case of an 8-year-old Moroccan girl who presented with a 1-year history of epileptic seizure, headache, and decreased visual acuity. Cranial magnetic resonance imaging revealed a right occipito-temporal mass. A tumor resection was performed and histological examination combined with immunohistochemical study confirmed the diagnosis of low-grade astroblastoma. Conclusions Astroblastoma is a very rare primary brain tumor. Its diagnosis is often challenging because of the astroblastic aspects that can be found in astrocytic tumors, in ependymomas, and in non-neuroepithelial tumors. Considerable confusion surrounds its histogenesis and classification. The low incidence rate makes it difficult to conduct studies to examine tumor characteristics.