A comprehensive histomolecular characterization of meningioangiomatosis: Further evidence for a precursor neoplastic lesion.

Meningioangiomatosis (MAM) remains a poorly understood lesion responsible for epileptic disease. In the past, MAM was primarily described in the context of neurofibromatosis type 2 before being mainly reported sporadically. Moreover, the malformative or tumoral nature is still debated. Because a subset of MAM are associated with meningiomas, some authors argue that MAM corresponds to an infiltration pattern of these tumors. For these reasons, MAM has not been added to the World Health Organization (WHO) Classification of Central Nervous System Tumors as a specific entity. In the present study, we characterized a series of pure MAM (n = 7) and MAM associated with meningiomas (n = 4) using histopathology, immunohistochemistry, genetic (fluorescent in situ and DNA sequencing analyses), and epigenetic (DNA-methylation profiling) data. We evidenced two distinct morphological patterns: MAM with a fibroblastic-like pattern having few lesional cells, and MAM with a more cellular pattern. A subset was associated with the genetic alterations previously reported in meningiomas (such as a KMT2C mutation and a hemizygous deletion of chromosome 22q including the NF2 gene). The DNA-methylation profile, using a t-distributed stochastic neighbor embedding analysis, evidenced that MAM (pure or associated with meningiomas) clustered in a separate group from pediatric meningiomas. The present results seem to suggest that MAM represents a neoplastic lesion and encourage the further study of similar additional series so that it may be included in a future WHO classification.

CNS tumors with PLAGL1-fusion: beyond ZFTA and YAP1 in the genetic spectrum of supratentorial ependymomas.

A novel methylation class, "neuroepithelial tumor, with PLAGL1 fusion" (NET-PLAGL1), has recently been described, based on epigenetic features, as a supratentorial pediatric brain tumor with recurrent histopathological features suggesting an ependymal differentiation. Because of the recent identification of this neoplastic entity, few histopathological, radiological and clinical data are available. Herein, we present a detailed series of nine cases of PLAGL1-fused supratentorial tumors, reclassified from a series of supratentorial ependymomas, non-ZFTA/non-YAP1 fusion-positive and subependymomas of the young. This study included extensive clinical, radiological, histopathological, ultrastructural, immunohistochemical, genetic and epigenetic (DNA methylation profiling) data for characterization. An important aim of this work was to evaluate the sensitivity and specificity of a novel fluorescent in situ hybridization (FISH) targeting the PLAGL1 gene. Using histopathology, immunohistochemistry and electron microscopy, we confirmed the ependymal differentiation of this new neoplastic entity. Indeed, the cases histopathologically presented as "mixed subependymomas-ependymomas" with well-circumscribed tumors exhibiting a diffuse immunoreactivity for GFAP, without expression of Olig2 or SOX10. Ultrastructurally, they also harbored features reminiscent of ependymal differentiation, such as cilia. Different gene partners were fused with PLAGL1: FOXO1, EWSR1 and for the first time MAML2. The PLAGL1 FISH presented a 100% sensitivity and specificity according to RNA sequencing and DNA methylation profiling results. This cohort of supratentorial PLAGL1-fused tumors highlights: 1/ the ependymal cell origin of this new neoplastic entity; 2/ benefit of looking for a PLAGL1 fusion in supratentorial cases of non-ZFTA/non-YAP1 ependymomas; and 3/ the usefulness of PLAGL1 FISH.

An immune signature of postoperative cognitive decline in elderly patients.

Postoperative cognitive decline (POCD) is the predominant complication affecting elderly patients following major surgery, yet its prediction and prevention remain challenging. Understanding biological processes underlying the pathogenesis of POCD is essential for identifying mechanistic biomarkers to advance diagnostics and therapeutics. This longitudinal study involving 26 elderly patients undergoing orthopedic surgery aimed to characterize the impact of peripheral immune cell responses to surgical trauma on POCD. Trajectory analyses of single-cell mass cytometry data highlighted early JAK/STAT signaling exacerbation and diminished MyD88 signaling post-surgery in patients who developed POCD. Further analyses integrating single-cell and plasma proteomic data collected before surgery with clinical variables yielded a sparse predictive model that accurately identified patients who would develop POCD (AUC = 0.80). The resulting POCD immune signature included one plasma protein and ten immune cell features, offering a concise list of biomarker candidates for developing point-of-care prognostic tests to personalize perioperative management of at-risk patients. The code and the data are documented and available at https://github.com/gregbellan/POCD . Teaser: Modeling immune cell responses and plasma proteomic data predicts postoperative cognitive decline.

Radiographic growth rate as a predictor of aggressiveness of diffuse gliomas without 1p19q codeletion.

OBJECTIVE: The 2021 WHO classification of CNS tumors has refined the definition of adult-type diffuse gliomas without 1p19q codeletion. Nevertheless, the aggressiveness of gliomas is based exclusively on histomolecular criteria performed on a limited sample of the tumor. The authors aimed to assess whether the spontaneous radiographic tumor growth rate is associated with tumor aggressiveness and allows preoperative identification of malignancy grade of adult-type diffuse gliomas without 1p19q codeletion. METHODS: The authors retrospectively reviewed the records of adult patients harboring a newly diagnosed supratentorial diffuse glioma without 1p19q codeletion, with available preoperative MRI follow-up between January 2008 and April 2022. The spontaneous radiographic tumor growth rate was quantified by tumor volume segmentation and regression of the evolution of the mean tumor diameter over time and was compared with clinical, imaging, histomolecular, and survival data. RESULTS: Ninety-six patients were included. The spontaneous radiographic tumor growth rates (mean 17.8 ± 38.8 mm/year, range 0-243.5 mm/year) significantly varied according to IDH1/2 mutation (p < 0.001), grade of malignancy (p < 0.001), and presence of microvascular proliferation (p < 0.001). The spontaneous radiographic tumor growth rate allowed preoperative identification of high-grade cases: 100% of grade 3 and 4 IDH-mutant diffuse astrocytomas had a spontaneous radiographic tumor growth rate ≥ 8.0 mm/year, and 100% of IDH-wild-type glioblastomas had a spontaneous radiographic tumor growth rate ≥ 42.0 mm/year. A spontaneous radiographic growth rate ≥ 8.0 mm/year was an independent predictor of shorter progression-free (p = 0.014) and overall (p = 0.007) survival. A mitotic count threshold ≥ 4 mitoses was the optimal threshold for identifying aggressive IDH-mutant astrocytomas based on spontaneous radiographic tumor growth. CONCLUSIONS: The spontaneous radiographic tumor growth rates could be used as an additional tool to preoperatively screen tumor aggressiveness of adult-type diffuse gliomas without 1p19q codeletion.

"Hemispheric pilocytic astrocytoma" revisited: A comprehensive clinicopathological and molecular series emphasizing their overlap with other glioneuronal tumors.

Pilocytic astrocytomas (PA) typically exhibit distinct clinical, radiological, histopathological, and genetic features. DNA-methylation profiling distinguishes PA according to their location (infratentorial, midline, hemispheric, or spinal). In the hemispheric location, distinguishing PA from glioneuronal tumors remains a common diagnostic challenge for neuropathologists. Furthermore, the current version of the DKFZ classifier seems to have difficulty separating them from gangliogliomas. In this study, after central radiological review, we identified a histopathologically defined set of PA (histPA, n = 11) and a cohort of DNA-methylation defined PA (mcPA, n = 11). Nine out of the 11 histPA matched the methylation class of hemispheric PA, whereas 2 cases were classified at the end of the study as dysembryoplastic neuroepithelial tumors. Similarly, the mcPA cohort contained tumors mainly classified as PA (7/11), but 4 cases were classified as glioneuronal. The analysis of the 16 tumors with an integrated diagnosis of PA revealed that they affect mainly children with a wide spectrum of radiological, histopathological (i.e. a predominantly diffuse growth pattern), and genetic characteristics (large range of mitogen-activated protein kinase alterations). Based on these results, we consider hemispheric PA to be different from their counterparts in other locations and to overlap with other glioneuronal tumors, reinforcing the necessity of interpreting all data to obtain an accurate diagnosis.

Characteristics and Prognosis of Tumor-Related Epilepsy During Tumor Evolution in Patients With IDH Wild-Type Glioblastoma.

BACKGROUND AND OBJECTIVES: Tumor-related epilepsy is a well-known symptom of glioblastoma. However, the particular characteristics of epileptic seizures related to glioblastoma, isocitrate dehydrogenase (IDH)-wild-type is almost unexplored longitudinally during the whole course of the disease. We assessed tumor-related epilepsy and seizure control during tumor evolution and the prognostic significance of tumor-related epilepsy. METHODS: We performed an observational, retrospective single-center study at one tertiary referral neuro-oncology surgical center (2000-2020). We included adult patients treated for a newly diagnosed supratentorial glioblastoma, IDH-wild-type with available preoperative and postoperative MRI and with available epileptic seizure status at diagnosis. To determine factors associated with tumor-related epilepsy or seizure control, univariate analyses were performed using the χ2 or Fisher exact tests for categorical variables and the unpaired t test or Mann-Whitney rank-sum test for continuous variables. Predictors associated with tumor-related epilepsy and seizure control in unadjusted analysis were entered into backward stepwise logistic regression models. RESULTS: One thousand six patients were enrolled. The cumulative incidence of tumor-related epilepsy increased during tumor evolution (33.1% at diagnosis, 44.7% after oncologic treatment, 52.4% at progression, and 51.8% at the end-of-life phase) and is related to tumor features (cortex involvement, no necrosis, and small volume). Uncontrolled epileptic seizures increased during tumor evolution (20.1% at diagnosis, 32.0% after oncologic treatment, 46.7% at progression, and 41.1% at the end-of-life phase). Epileptic seizure control after oncologic treatment was related to seizure features (uncontrolled before oncologic treatment and focal-to-bilateral tonic-clonic seizures) and to the extent of resection. Epileptic seizure control at tumor progression was related to seizure features (presence at diagnosis and uncontrolled after oncologic treatment) and to the time to progression. Tumor-related epilepsy at diagnosis was a predictor of a longer overall survival (adjusted hazard ratio, 0.78; 95% CI 0.67-0.90; p < 0.001) independent of age, Karnofsky Performance Status score, tumor location and volume, extent of resection, standard combined chemoradiotherapy, levetiracetam use, and MGMT promoter methylation. DISCUSSION: The progression of tumor-related epilepsy with the evolution of glioblastoma, IDH-wild-type and the effects of surgery on seizure control argue for proper antiseizure medication and maximal safe resection. Tumor-related epilepsy is an independent predictor of a longer survival.

Presentation and Management of Cerebral Venous Sinus Thrombosis After Supratentorial Craniotomy.

BACKGROUND AND OBJECTIVES: Cerebral venous sinus thrombosis (CVST) after supratentorial craniotomy is a poorly studied complication, for which there are no management guidelines. This study assessed the incidence, associated risk factors, and management of postoperative CVST after awake craniotomy. METHODS: This is an observational, retrospective, monocentric analysis of patients who underwent a supratentorial awake craniotomy. Postoperative CVST was defined as a flow defect on the postoperative contrast-enhanced 3D T1-weighted sequence and/or as a T2* hypointensity within the sinus. RESULTS: In 401 supratentorial awake craniotomies (87.3% of diffuse glioma), the incidence of postoperative CVST was 4.0% (95% CI 2.5-6.4): 14/16 thromboses located in the superior sagittal sinus and 12/16 located in the transverse sinus. A venous sinus was exposed during craniotomy in 45.4% of cases, and no intraoperative injury to a cerebral venous sinus was reported. All thromboses were asymptomatic, and only two cases were diagnosed at the time of the first postoperative imaging (0.5%). Postoperative complications, early postoperative Karnofsky Performance Status score, and duration of hospital stay did not significantly differ between patients with and without postoperative CVST. Adjusted independent risk factors of postoperative CVST were female sex (adjusted Odds Ratio 4.00, 95% CI 1.24-12.91, P = .021) and a lesion ≤1 cm to a venous sinus (adjusted Odds Ratio 10.58, 95% CI 2.93-38.20, P < .001). All patients received standard prophylactic-dose anticoagulant therapy, and none received treatment-dose anticoagulant therapy. No thrombosis-related adverse event was reported. All thromboses presented spontaneous sinus recanalization radiologically at a mean of 89 ± 41 days (range, 7-171). CONCLUSION: CVST after supratentorial awake craniotomy is a rare event with satisfactory clinical outcomes and spontaneous sinus recanalization under conservative management without treatment-dose anticoagulant therapy. These findings are comforting to neurosurgeons confronted with postoperative MRI reports suggesting CVST.

Efficacy and Safety of Carmustine Wafer Implantation After Ventricular Opening in Glioblastomas, Isocitrate Dehydrogenase-Wildtype, in Adults.

BACKGROUND AND OBJECTIVES: We assessed the impact of ventricular opening on postoperative complications and survival of carmustine wafer implantation during surgery of newly diagnosed supratentorial glioblastomas, isocitrate dehydrogenase (IDH)-wildtype in adults. METHODS: We performed an observational, retrospective, single-center cohort study at a tertiary surgical neuro-oncological center between January 2006 and December 2021. RESULTS: One hundred ninety-four patients who benefited from a first-line surgical resection with carmustine wafer implantation were included. Seventy patients (36.1%) had a ventricular opening. We showed that ventricular opening (1) did not increase overall postoperative complication rates (P = .201); (2) did not worsen the early postoperative Karnofsky Performance Status score (P = .068); (3) did not increase the time interval from surgery to adjuvant oncological treatment (P = .458); (4) did not affect the completion of the standard radiochemotherapy protocol (P = .164); (5) did not affect progression-free survival (P = .059); and (6) did not affect overall survival (P = .142). CONCLUSION: In this study, ventricular opening during first-line surgical resection did not affect the survival and postoperative complications after use of carmustine wafer implantation in adult patients with a newly diagnosed supratentorial glioblastoma, IDH-wildtype. This warrants a prospective and multicentric study to clearly assess the impact of the ventricular opening after carmustine wafer implantation in glioblastoma, IDH-wildtype.

CNS erythroblastic sarcoma: a potential emerging pediatric tumor type characterized by NFIA::RUNX1T1/3 fusions.

Erythroblastic sarcoma (ES) (previously called chloroma or granulocytic sarcoma) are rare hematological neoplams characterized by the proliferation of myeloid blasts at extramedullary sites, and primarily involve the skin and soft tissue of middle-aged adults. ES may be concomitant with or secondary to myeloid neoplasms (mostly acute myeloid leukemia (AML)) or in isolated cases (de novo) without infiltration of the bone marrow by blasts. ES share cytogenetic and molecular abnormalities with AML, including RUNX1T1 fusions. Some of these alterations seem to be correlated with particular sites of involvement. Herein, we report an isolated erythroblastic sarcoma with NFIA::RUNX1T1 located in the central nervous system (CNS) of a 3-year-old boy. Recently, two pediatric cases of CNS MS with complete molecular characterization have been documented. Like the current case, they concerned infants (2 and 3 years-old) presenting a brain tumor (pineal involvement) with leptomeningeal dissemination. Both cases also harbored a NFIA::RUNX1T3 fusion. ES constitutes a diagnostic challenge for neuropathologists because it does not express differentiation markers such as CD45, and may express CD99 which could be confused with CNS Ewing sarcoma. CD43 is the earliest pan-hematopoietic marker and CD45 is not expressed by erythroid lineage cells. E-cadherin (also a marker of erythroid precursors) and CD117 (expressed on the surface of erythroid lineage cells) constitute other immunhistochemical hallmarks of ES. The prognosis of patients with ES is similar to that of other patients with AML but de novo forms seem to have a poorer prognosis, like the current case. To conclude, pediatric ES with NFIA::RUNX1T1/3 fusions seem to have a tropism for the CNS and thus constitute a potential pitfall for neuropathologists. Due to the absence of circulating blasts and a DNA-methylation signature, the diagnosis must currently be made by highlighting the translocation and expression of erythroid markers.

Use of MR signal intensity variations to highlight structures at risk along brain biopsy trajectories.

OBJECTIVE: Postoperative intracerebral hemorrhages are significant complications following brain stereotactic biopsy. They can derive from anatomical structure (sulci, vessels) damage that is missed during stereotactic trajectory planning. In this study, the authors investigated the ability to detect contact between structures at risk and stereotactic trajectories using signal analysis from MRI obtained during clinical practice, with the aim to propose a visual tool to highlight areas with anatomical structures at risk of damage along the biopsy trajectory. METHODS: The authors retrospectively analyzed actual stereotactic trajectories using intraoperative imaging (intraoperative 2D radiographs in the exploratory data set and intraoperative 3D scans in the confirmatory data set). The MR signal variation along each biopsy trajectory was matched with the patient's anatomy. RESULTS: In the exploratory data set (n = 154 patients), 32 contacts between the actual biopsy trajectory and an anatomical structure at risk were identified along 28 (18.2%) biopsy trajectories, corresponding to 8 preventable intracerebral hemorrhages. Variations of the mean derivative of the MR signal intensity were significantly different between trajectories with and without contact (the pathological threshold of the mean derivative of the MR signal intensity was defined as ± 0.030 arbitrary units; p < 0.0001), with a sensitivity of 89.3% and specificity of 74.6% to detect a contact. In the confirmatory data set (n = 73 patients), the sensitivity and specificity of the 0.030 threshold to detect a contact between the actual stereotactic trajectory and an anatomical structure at risk were 81.3% and 68.4%, respectively. CONCLUSIONS: Variations of the mean derivative of the MR signal intensity can be converted into a green/red color code along the planned biopsy trajectory to highlight anatomical structures at risk, which can help neurosurgeons during the surgical planning of stereotactic procedures.

The pontine diffuse midline glioma, EGFR-subtype with ependymal features: Yet another face of diffuse midline glioma, H3K27-altered.

Diffuse midline glioma with two components: classical glial and ependymal.

[Contributions and limitations of FISH analysis for the diagnosis of central nervous system tumors according to the 2021 WHO classification: Feedback from Sainte-Anne Hospital's Department of Neuropathology]. / Apports et limites de la FISH dans le diagnostic des tumeurs du système nerveux central selon la classification de l'OMS de 2021 : retour d'expérience du service de neuropathologie de l'hôpital Sainte-Anne.

The fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System has identified many new tumor types and has established, for the first time, essential and desirable diagnostic criteria for each of them. Among these, genetic alterations play an important role associated with morphology. For the first time, epigenetic data can also constitute essential and/or desirable criteria. These genetic abnormalities can be fusions, deletions or gains/amplifications and can thus be detected by fluorescence in situ hybridization techniques. The purpose of this article is to present the advantages and limitations of this technique in reference to its specific use within neuro-oncopathology in light of the 2021 WHO classification.

Carmustine wafer implantation for supratentorial glioblastomas, IDH-wildtype in "extreme" neurosurgical conditions.

We assessed the feasibility of Carmustine wafer implantation in "extreme" conditions (i.e. patients > 80 years and Karnofsky Performance Status score < 50) and of implantation ≥ 12 Carmustine wafers in adult patients harbouring a newly diagnosed supratentorial glioblastoma, IDH-wildtype. We performed an observational, retrospective single-centre cohort study at a tertiary surgical neuro-oncological centre between January 2006 and December 2021. Four hundred eighty patients who benefited from a surgical resection at first-line treatment were included. We showed that Carmustine wafer implantation in patients > 80 years, in patients with a Karnofsky performance status score < 50, and that implantation ≥ 12 Carmustine wafers (1) did not increase overall postoperative complication rates, (2) did not affect the completion of standard radiochemotherapy protocol, (3) did not worsen the postoperative Karnofsky Performance Status scores, and (4) did not significantly affect the time to oncological treatment. We showed that the implantation of ≥ 12 Carmustine wafers improved progression-free survival (31.0 versus 10.0 months, p = 0.025) and overall survival (39.0 versus 16.5 months, p = 0.041) without increasing postoperative complication rates. Carmustine wafer implantation during the surgical resection of a newly diagnosed supratentorial glioblastoma, IDH-wildtype is safe and efficient in patients > 80 years and in patients with preoperative Karnofsky Performance Status score < 50. The number of Carmustine wafers should be adapted (up to 16 in our experience) to the resection cavity to improve survival without increasing postoperative overall complication rates.

A comprehensive analysis of infantile central nervous system tumors to improve distinctive criteria for infant-type hemispheric glioma versus desmoplastic infantile ganglioglioma/astrocytoma.

Recent epigenomic analyses have revealed the existence of a new DNA methylation class (MC) of infant-type hemispheric glioma (IHG). Like desmoplastic infantile ganglioglioma/astrocytoma (DIG/DIA), these tumors mainly affect infants and are supratentorial. While DIG/DIA is characterized by BRAF or RAF1 alterations, IHG has been shown to have receptor tyrosine kinase (RTK) gene fusions (ALK, ROS1, NTRK1/2/3, and MET). However, in this rapidly evolving field, a more comprehensive analysis of infantile glial/glioneuronal tumors including clinical, radiological, histopathological, and molecular data is needed. Here, we retrospectively investigated data from 30 infantile glial/glioneuronal tumors, consecutively compiled from our center. They were analyzed by two experienced pediatric neuroradiologists in consensus, without former knowledge of the molecular data. We also performed a comprehensive clinical, and histopathological examination (including molecular evaluation by next-generation sequencing, RNA sequencing, and fluorescence in situ hybridization [FISH] analyses), as well as DNA methylation profiling for the samples having sufficient material available. The integrative histopathological, genetic, and epigenetic analyses, including t-distributed stochastic neighbor embedding (t-SNE) analyses segregated tumors into 10 DIG/DIA (33.3%), six IHG (20.0%), three gangliogliomas (10.0%), two pleomorphic xanthoastrocytomas (6.7%), two pilocytic astrocytomas (6.7%), two supratentorial ependymomas, ZFTA fusion-positive (6.7%), two supratentorial ependymomas, YAP1 fusion-positive (6.7%), two embryonal tumors with PLAGL2-family amplification (6.7%), and one diffuse low-grade glioma, MAPK-pathway altered. This study highlights the significant differential features, in terms of histopathology (leptomeningeal infiltration, intense desmoplasia and ganglion cells in DIG/DIA and necrosis, microvascular proliferation, and siderophages in IHG), and radiology between DIG/DIA and IHG. Moreover, these results are consistent with the literature data concerning the molecular dichotomy (BRAF/RAF1 alterations vs. RTK genes' fusions) between DIG/DIA and IHG. This study characterized histopathologically and radiologically two additional cases of the novel embryonal tumor characterized by PLAGL2 gene amplification.

A Preoperative Scoring System to Predict Function-Based Resection Limitation Due to Insufficient Participation During Awake Surgery.

BACKGROUND: Failure in achieving a function-based resection related to the insufficient patient's participation is a drawback of awake surgery. OBJECTIVE: To assess preoperative parameters predicting the risk of patient insufficient intraoperative cooperation leading to the arrest of the awake resection. METHODS: Observational, retrospective, multicentric cohort analysis enrolling 384 (experimental dataset) and 100 (external validation dataset) awake surgeries. RESULTS: In the experimental data set, an insufficient intraoperative cooperation occurred in 20/384 patients (5.2%), leading to awake surgery failure in 3/384 patients (ie, no resection, 0.8%), and precluded the achievement of the function-based resection in 17/384 patients (ie, resection limitation, 4.4%). The insufficient intraoperative cooperation significantly reduced the resection rates (55.0% vs 94.0%, P < .001) and precluded a supratotal resection (0% vs 11.3%, P = .017). Seventy years or older, uncontrolled epileptic seizures, previous oncological treatment, hyperperfusion on MRI, and mass effect on midline were independent predictors of insufficient cooperation during awake surgery ( P < .05). An Awake Surgery Insufficient Cooperation score was then assessed: 96.9% of patients (n = 343/354) with a score ≤2 presented a good intraoperative cooperation, while only 70.0% of patients (n = 21/30) with a score >2 presented a good intraoperative cooperation. In the experimental data set, similar date were found: 98.9% of patients (n = 98/99) with a score ≤2 presented a good cooperation, while 0% of patients (n = 0/1) with a score >2 presented a good cooperation. CONCLUSION: Function-based resection under awake conditions can be safely performed with a low rate of insufficient patient intraoperative cooperation. The risk can be assessed preoperatively by a careful patient selection.

CNS tumor with EP300::BCOR fusion: discussing its prevalence in adult population.

The Central Nervous System (CNS) tumor with BCOR internal tandem duplication (ITD) has recently been added as a novel embryonal histomolecular tumor type to the 2021 World Health Organization (WHO) Classification of CNS Tumors. In addition, other CNS tumors harboring a BCOR/BCORL1 fusion, which are defined by a distinct DNA-methylation profile, have been recently identified in the literature but clinical, radiological and histopathological data remain scarce. Herein, we present two adult cases of CNS tumors with EP300::BCOR fusion. These two cases presented radiological, histopathological, and immunohistochemical homologies with CNS tumors having BCOR ITD in children. To compare these tumors with different BCOR alterations, we performed a literature review with a meta-analysis. CNS tumors with EP300::BCOR fusion seem to be distinct from their BCOR ITD counterparts in terms of age, location, progression-free survival, tumor growth pattern, and immunopositivity for the BCOR protein. CNS tumors from the EP300::BCOR fusion methylation class in adults may be added to the future WHO classification.