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.

Sentinel report of uniquely paired collision tumors: glioblastoma multiforme and coexistent intraventricular subependymoma. Illustrative case.

BACKGROUND: The presence of intracranial collision tumors, histologically distinct tumors occurring in anatomical proximity, is quite rare. Herein, the authors describe the sentinel case of a contiguous collision tumor combination consisting of glioblastoma multiforme and intraventricular subependymoma. OBSERVATIONS: A 67-year-old male presented with several months of progressive fatigue superimposed on more recently noted word-finding difficulty, slight left-sided weakness, and episodic confusion. He was found to have a large right frontal mass abutting the right lateral ventricle with an additional nodular focus of enhancement within the right frontal horn. The patient underwent an awake right frontal craniotomy for gross-total resection of the tumor, noted to be of two distinct histological identities. LESSONS: Although exceptionally rare, primary glial neoplasms of various histologies can be encountered simultaneously during resection, as in this case of co-occurring glioblastoma of the right frontal lobe and right frontal horn intraventricular subependymoma. Close attention to tumoral locations and the gross appearance of specimens during resection can prime the operative neurosurgeon for success in contributing to accurate diagnoses through sending separate pathological specimens for histological analysis when qualitatively different tissue is suspected.

Intraventricular Subependymoma With Obstructive Hydrocephalus: A Case Report and Literature Review.

Subependymomas are benign tumors of the ventricles that grow from the ventricular wall into the cerebrospinal fluid spaces within the brain, obstructing the flow of the cerebrospinal fluid and causing obstructive hydrocephalus. It is estimated that ependymomas represent between 0.2% and 0.7% of all intracranial tumors. They arise most frequently in the fourth ventricle (50-60%) and the lateral ventricles (30-40%). We present the case of a 50-year-old patient, previously diagnosed with an intraventricular process, admitted in our clinic. At neurological examination, the patient was cooperative, bradylalic, and bradypsychic, with right hemiparesis, postural and balance disorders, and occasionally sphincteric incontinence. MRI with contrast described a left intraventricular tumor, in the frontal horn of the left lateral ventricle with homogeneous appearance, with a maximum diameter of 50 mm and base of insertion at the adjacent ependyma of the foramen of Monro, which determined obstructive hydrocephalus. Total resection of the left intraventricular cerebral tumor was achieved. Histopathological analysis revealed a subependymoma. Postoperative recovery was slowly favorable, with significant neurological improvement. At neurological examination at three-month follow-up, the patient's right hemiparesis and unsystematized balance disorders improved. A contrast-enhanced CT scan was performed, highlighting left frontal sequelae hypodensity corresponding to the operated tumor, enlarged left lateral ventricle without active hydrocephalus, and no sign of tumor recurrence. At six-month follow-up, clinico-radiologic findings coincide with those from three-month follow-up. Subependymomas are slow-growing (grade 1) tumors and generally have a favorable prognosis. Unfortunately, due to their anatomical level, multiple complications can arise, caused from obstructive hydrocephalus complications, such as cognitive dysfunction and incontinence. Tumor resection should be complete, a successful operation being a challenge for every neurosurgeon.

Intraoperative discovery of a radiographically occult subependymoma obstructing the obex in a patient with a Chiari malformation - A rare case.

Background: Chiari (type I) malformations are typically congenital. Occasionally, however, tonsillar herniation can arise secondary to cerebrospinal fluid leakage, posterior fossa or intraventricular mass lesions, or other etiologies. We present the first-ever case of an intramedullary subependymoma at the cervicomedullary junction associated with vertebral bone abnormalities and an acquired secondary Chiari malformation. Case Description: A 60-year-old woman presented with a 3-year history of occipital, tussive headaches. Preoperative imaging was negative for mass lesions but demonstrated a Chiari malformation. She was recommended posterior fossa decompression with tonsillar shrinkage. During surgery, an intramedullary mass was incidentally observed, obstructing the obex at the cervicomedullary junction. Histopathological analysis of the resected lesion revealed a diagnosis of subependymoma. Conclusion: Subependymomas can sometimes present a diagnostic challenge due to their subtle appearance in neuroimaging. Only rarely are such masses associated with an acquired Chiari malformation. No such case has previously been reported. We present a literature review on acquired Chiari malformations and discuss their management.

Immunohistochemical analyses of neural stem cell lineage markers in normal feline brains and glial tumors.

Neural stem cell (NSC) lineage cells have not been fully identified in feline brains, and the NSC-like nature of feline glial tumors has not been determined. In this study, 6 normal cat brains (3 newborn and 3 older cats) and 13 feline glial tumors were analyzed using immunohistochemical NSC lineage markers. The feline glial tumors were subjected to immunohistochemical scoring followed by hierarchical cluster analysis. In newborn brains, glial acidic fibrillary protein (GFAP)/nestin/sex-determining region Y-box transcription factor 2 (SOX2)-immunopositive NSCs, SOX2-immunopositive intermediate progenitor cells, oligodendrocyte transcription factor 2 (OLIG2)/platelet-derived growth factor receptor-α (PDGFR-α)-immunopositive oligodendrocyte precursor cells (OPCs), OLIG2/GFAP-immunopositive immature astrocytes, and neuronal nuclear (NeuN)/ß-3 tubulin-immunopositive mature neuronal cells were observed. The apical membrane of NSCs was also immunopositive for Na+/H+ exchanger regulatory factor 1 (NHERF1). In mature brains, the NSC lineage cells were similar to those of the newborn brains. A total of 13 glial tumors consisted of 2 oligodendrogliomas, 4 astrocytomas, 3 subependymomas, and 4 ependymomas. Astrocytomas, subependymomas, and ependymomas were immunopositive for GFAP, nestin, and SOX2. Subependymomas and ependymomas showed dot-like or apical membrane immunolabeling for NHERF1, respectively. Astrocytomas were immunopositive for OLIG2. Oligodendrogliomas and subependymomas were immunopositive for OLIG2 and PDGFR-α. Feline glial tumors also showed variable immunolabeling for ß-3 tubulin, NeuN, and synaptophysin. Based on these results, feline astrocytomas, subependymomas, and ependymomas appear to have an NSC-like immunophenotype. In addition, astrocytomas, subependymomas, and ependymomas have the characteristics of glial, oligodendrocyte precursor, and ependymal cells, respectively. Feline oligodendrogliomas likely have an OPC-like immunophenotype. In addition, feline glial tumors may have multipotential stemness for differentiation into neuronal cells. These preliminary results should be validated by gene expression analyses in future studies with larger case numbers.

Disappearance of a Ruptured Feeding Artery Fusiform Aneurysm After the Resection of a Large Subependymoma: A Case Report.

Aneurysm formation on the tumor-feeding artery is rare, and its treatment strategies are not yet settled. We herein report the case of a 49-year-old female with a large subependymoma in the left lateral ventricle presenting remote intracerebral hemorrhage at the left posterior cingulate gyrus. Digital subtraction angiography (DSA) revealed the presence of a 5.5 mm fusiform tumor-feeding artery aneurysm on the left parieto-occipital branch of the posterior cerebral artery, considered to be the source of the hemorrhage. Three months after total tumor resection, the aneurysm subsequently disappeared on the follow-up angiography. Subependymomas are generally known as tumors with low vascularity and seldom present with symptoms such as intracerebral hemorrhage. From the subsequent disappearance of the aneurysm after the complete tumor resection, the pathophysiological cause of the aneurysm formation is assumed to be flow-related hemodynamic vessel wall stress of the feeding artery. Tumor resection alone may be a favorable first treatment strategy to avoid unnecessary brain damage since subsequent disappearance of the aneurysm can be expected. The coexistence of feeding artery aneurysms should be kept in mind, especially in cases with remote hemorrhage.

Subependymomas of the fourth ventricle: To operate or not to operate?

BACKGROUND: There is a paucity of literature regarding the clinical characteristics and management of subependymomas of the fourth ventricle due to their rarity. Here, we describe the operative and non-operative management and outcomes of patients with such tumors. METHODS: This retrospective single-institution case series was gathered after Institutional Review Board (IRB) approval. Patients diagnosed with a subependymoma of the fourth ventricle between 1993 and 2021 were identified. Clinical, radiology and pathology reports along with magnetic resonance imaging (MRI) images were reviewed. RESULTS: Patients identified (n = 20), showed a male predominance (n = 14). They underwent surgery (n = 9) with resection and histopathological confirmation of subependymoma or were followed with imaging surveillance (n = 11). The median age at diagnosis was 51.5 years. Median tumor volume for the operative cohort was 8.64 cm3 and median length of follow-up was 65.8 months. Median tumor volume for the non-operative cohort was 0.96 cm3 and median length of follow-up was 78 months. No tumor recurrence post-resection was noted in the operative group, and no tumor growth from baseline was noted in the non-operative group. Most patients (89 %) in the operative group had symptoms at diagnosis, all of which improved post-resection. No patients were symptomatic in the non-operative group. CONCLUSIONS: Surgical resection is safe and is associated with alleviation of presenting symptoms in patients with large tumors. Observation and routine surveillance are warranted for smaller, asymptomatic tumors.

Resection of intradural intramedullary subependymoma of the cervicothoracic spine: 2-dimensional operative video.

This video presents the case of a 44-year-old male with a 2-year history of pain in the left upper extremity that had worsened over the course of the last 6 months with associated weakened grip strength and had extended into his right arm. T2-weighted sagittal and axial MRI demonstrated an expansive nonenhancing solid intramedullary lesion extending from C5 to T1. The patient underwent a C5-T1 laminectomy and laminoplasty with near-complete resection of the intradural intramedullary subependymoma. At 3 months' follow-up, he reported doing well and had experienced significant improvement in motor strength with ongoing therapies.

Surgical resection of recurrent intramedullary subependymoma of the cervical spinal cord.

Spinal subependymomas (SE) are rare, often indolent benign tumors presenting most frequently as intramedullary tumors in the cervical spine or cervicothoracic junction. When symptomatic, patients often present with years of sensory changes, weakness, paresthesias, or bowel and bladder dysfunction. Preoperatively, SE are difficult to distinguish radiographically from ependymomas or astrocytomas; however, it is important to make the distinction intraoperatively as complete resection can be curative. Here the authors present a rare case of recurrent, symptomatic cervical subependymoma which underwent gross-total resection and discussion of management strategies and outcomes of all SE at their institution.

Lateral ventricle subependymoma resected with a transcallosal approach: illustrative case.

BACKGROUND: Subependymomas are World Health Organization grade I tumors, and 30% occur in the lateral ventricles. Surgery is the mainstay of treatment, and the transcallosal or transcortical/transsulcal approaches are preferred for those tumors occurring near the foramen of Monro or atrium. Visualization, proximity to the fornix and basal ganglia, hydrocephalus, and brain retraction during surgery make these operations challenging. The authors present the case of a 65-year-old male with a subependymoma located in the left lateral ventricle. The tumor was completely resected using an interhemispheric/transcallosal approach. OBSERVATIONS: The authors analyze the anatomopathological features of subependymoma, along with the clinical behavior and therapeutic options. The authors discuss in detail the advantages and disadvantages of the interhemispheric/transcallosal approach for resection of these tumors. LESSONS: Subependymomas are slow-growing lesions with an indolent yet complicated course making surgical removal challenging yet feasible using the correct techniques. The interhemispheric transcallosal approach offers an excellent route for the resection of large subependymomas, but there is still a significant risk for postoperative complications.

Benign Glioma.

Benign glioma broadly refers to a heterogeneous group of slow-growing glial tumors with low proliferative rates and a more indolent clinical course. These tumors may also be described as "low-grade" glioma (LGG) and are classified as WHO grade I or II lesions according to the Classification of Tumors of the Central Nervous System (CNS) (Louis et al. in Acta Neuropathol 114:97-109, 2007). Advances in molecular genetics have improved understanding of glioma tumorigenesis, leading to the identification of common mutation profiles with significant treatment and prognostic implications. The most recent WHO 2016 classification system has introduced several notable changes in the way that gliomas are diagnosed, with a new emphasis on molecular features as key factors in differentiation (Wesseling and Capper in Neuropathol Appl Neurobiol 44:139-150, 2018). Benign gliomas have a predilection for younger patients and are among the most frequently diagnosed tumors in children and young adults (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). These tumors can be separated into two clinically distinct subgroups. The first group is of focal, well-circumscribed lesions that notably are not associated with an increased risk of malignant transformation. Primarily diagnosed in pediatric patients, these WHO grade I tumors may be cured with surgical resection alone (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). Recurrence rates are low, and the prognosis for these patients is excellent (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). Diffuse gliomas are WHO grade II lesions with a more infiltrative pattern of growth and high propensity for recurrence. These tumors are primarily diagnosed in young adult patients, and classically present with seizures (Pallud et al. Brain 137:449-462, 2014). The term "benign" is a misnomer in many cases, as the natural history of these tumors is with malignant transformation and recurrence as grade III or grade IV tumors (Jooma et al. in J Neurosurg 14:356-363, 2019). For all LGG, surgery with maximal safe resection is the treatment of choice for both primary and recurrent tumors. The goal of surgery should be for gross total resection (GTR), as complete tumor removal is associated with higher rates of tumor control and seizure freedom. Chemotherapy and radiation therapy (RT), while not typically a component of first-line treatment in most cases, may be employed as adjunctive therapy in high-risk or recurrent tumors and in some select cases. The prognosis of benign gliomas varies widely; non-infiltrative tumor subtypes generally have an excellent prognosis, while diffusely infiltrative tumors, although slow-growing, are eventually fatal (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). This chapter reviews the shared and unique individual features of the benign glioma including diffuse glioma, pilocytic astrocytoma and pilomyxoid astrocytoma (PMA), subependymal giant cell astrocytoma (SEGA), pleomorphic xanthoastrocytoma (PXA), subependymoma (SE), angiocentric glioma (AG), and chordoid glioma (CG). Also discussed is ganglioglioma (GG), a mixed neuronal-glial tumor that represents a notable diagnosis in the differential for other LGG (Wesseling and Capper 2018). Ependymomas of the brain and spinal cord, including major histologic subtypes, are discussed in other chapters.

Bruns syndrome in a patient with intraventricular subependymoma: a case report.

Purpose: Subependymoma is a slow-growing benign brain neoplasm, classified by the World Health Organization (WHO) as a grade I tumor, which typically presents in middle-aged male adults. Case description: A case of Bruns syndrome and an intraventricular subependymoma in a 49-year-old patient who presented with intractable headache and vertigo is discussed in this paper. Imaging revealed a well-delimited cystic and solid mass near the lateral ventricle. Comment: Complete surgical excision of the tumor resulted in the restoration of normal cerebrospinal fluid pathway and resolution of clinical symptoms with no signs of tumor recurrence in the 4-year follow-up period.

Classification and neuroimaging of ependymal tumors.

Ependymal tumors arise from the ependymal cell remnants of the cerebral ventricles, the central canal of the spinal cord, or the filum terminale or conus medullaris, although most pediatric supratentorial ependymomas do not exhibit clear communication or abutment of the ventricles. In this article, we discuss the classification, imaging characteristics, and clinical settings of these tumors. The WHO 2021 classification system has categorized ependymal tumors based on histopathologic and molecular features and location, in which they are grouped as supratentorial, posterior fossa (PF), and spinal. The supratentorial tumors are defined by either the ZFTA (formerly RELA) fusion or the YAP1 fusion. Posterior fossa tumors are divided into group A and group B based on methylation. On imaging, supratentorial and infratentorial ependymomas may arise from the ventricles and commonly contain calcifications and cystic components, with variable hemorrhage and heterogeneous enhancement. Spinal ependymomas are defined by MYCN amplification. These tumors are less commonly calcified and may present with the "cap sign," with T2 hypointensity due to hemosiderin deposition. Myxopapillary ependymoma and subependymoma remain tumor subtypes, with no change related to molecular classification as this does not provide additional clinical utility. Myxopapillary ependymomas are intradural and extramedullary tumors at the filum terminale and/or conus medullaris and may also present the cap sign. Subependymomas are homogeneous when small and may be heterogeneous and contain calcifications when larger. These tumors typically do not demonstrate enhancement. Clinical presentation and prognosis vary depending on tumor location and type. Knowledge of the updated WHO classification of the central nervous system in conjunction with imaging features is critical for accurate diagnosis and treatment.

Spinal Cord Subependymoma: A Subanalysis of the Neurospinal Society of Japan's Multicenter Study of Intramedullary Spinal Cord Tumors.

OBJECTIVE: This study aimed to analyze the clinical characteristics, treatment strategies, and surgical outcomes of subependymoma patients from the 2022 Neurospinal Society of Japan multicenter intramedullary spinal cord tumor study. METHODS: Twenty-six patients with spinal cord subependymoma who were included in the index study of 1,033 patients were retrospectively analyzed. RESULTS: Mean patient age was 49.4 years. Seventeen patients were men and 9 were women. Sensory disturbance was reported in 22 patients and motor weakness in 18. Median duration of symptoms was 24 months. The tumor was eccentrically located in 19 patients (73.1%) and unilateral in 17 (65.4%). Gross total resection was achieved in 6 patients (23.1%). The same rate for ependymoma patients in the index study was significantly higher (74.8%). Median follow-up was 40.5 months (interquartile range, 18-68 months). In 2 patients who underwent only partial resection, reoperation was required owing to progression 68 and 90 months after surgery, respectively. No recurrence occurred in patients who underwent gross total resection. Five patients experienced neurological worsening after surgery. CONCLUSION: Although spinal cord subependymoma can be difficult to distinguish from other intramedullary spinal cord lesions before surgery, it is characterized by an indolent clinical course and eccentric location. Surgical treatment should prioritize functional preservation because the prognosis is good even after subtotal resection.

The Ribbon Sign as a Radiological Indicator of Intramedullary Spinal Cord Subependymomas.

OBJECTIVE: Intramedullary spinal cord (IMSC) subependymomas are rare World Health Organization grade 1 ependymal tumors. The potential presence of functional neural tissue within the tumor and poorly demarcated planes presents a risk to resection. Anticipating a subependymoma on preoperative imaging can inform surgical decision-making and improve patient counseling. Here, we present our experience recognizing IMSC subependymomas on preoperative magnetic resonance imaging (MRI) based on a distinctive characteristic termed the "ribbon sign." METHODS: We retrospectively reviewed preoperative MRIs of patients presenting with IMSC tumors at a large tertiary academic institution between April 2005 and January 2022. The diagnosis was confirmed histologically. The "ribbon sign" was defined as a ribbon-like structure of T2 isointense spinal cord tissue interwoven between regions of T2 hyperintense tumor. The ribbon sign was confirmed by an expert neuroradiologist. RESULTS: MRIs from 151 patients were reviewed, including 10 patients with IMSC subependymomas. The ribbon sign was demonstrated on 9 (90%) patients with histologically proven subependymomas. Other tumor types did not display the ribbon sign. CONCLUSION: The ribbon sign is a potentially distinctive imaging feature of IMSC subependymomas and indicates the presence of spinal cord tissue between eccentrically located tumors. Recognition of the ribbon sign should prompt clinicians to consider a diagnosis of subependymoma, aiding the neurosurgeon in planning the surgical approach and adjusting the surgical outcome expectation. Consequently, the risks and benefits of gross-versus subtotal resection for palliative debulking should be carefully considered and discussed with patients.

Clinical Characteristics, Management, and Outcomes of Intramedullary Spinal Cord Ependymomas in Adults: A Systematic Review.

BACKGROUND: Intramedullary spinal cord ependymomas (IMSCEs) are rare tumors that mostly occur in adults. Management strategies and related outcomes are heterogeneously reported across the literature, demanding a comprehensive analysis to standardize guidelines. We performed a systematic review of the literature on IMSCEs. METHODS: A literature search was conducted using 6 databases from inception up to July 28, 2022. Studies with data on clinical characteristics, management strategies, and related outcomes in adult patients with histopathologically confirmed IMSCEs were pooled and analyzed. RESULTS: The analysis included 69 studies comprising 457 patients (52.7% males). Mean age was 42.4 ± 7.4 years. Sensory deficit (58.0%) was the most prevalent symptom, followed by radicular pain (50.5%). Tumors mostly involved the cervical (64.4%) or thoracic (18.8%) spinal cord and were mostly World Health Organization grade II (80.5%) and classic subtype (72.4%). Gross total resection was performed in most cases (83.4%), with adjuvant radiotherapy delivered in 10.5% of cases. Progression-free survival ≥2 years was reported in 61.1% of cases, and tumor recurrence or progression was reported in only 7.0% of the patients. At last follow-up, 97.4% of patients were alive. CONCLUSIONS: IMSCEs are uncommon tumors that frequently manifest with debilitating symptoms that require surgical treatment. When feasible, gross total resection may be pursued to improve the patient's functional status and prevent tumor progression, with adjuvant radiotherapy required only in some more aggressive grade III lesions. Future studies should investigate different growth patterns and prognoses based on different IMSCE subtypes.

Coexistence of Two Distinct Tumor Types Within One Posterior Fossa Mass Lesion in an Adult Patient Verified by DNA-Methylation Analysis: A Case Report.

We report an 81-year-old patient who underwent microsurgical resection of a posterior fossa mass lesion. Intraoperative findings were suggestive of the presence of two distinctly different tumor types within the lesion, one of which was well-circumscribed and avascular, whereas the other one showed an adhesive growth pattern and extensive vascularisation. Histopathological analysis, including deoxyribonucleic acid (DNA)-methylation-based classification, substantiated the intraoperative impression and confirmed the presence of a subependymoma central nervous system (CNS) World Health Organization (WHO) grade 1 as well as the presence of a hemangioblastoma CNS WHO grade 1. To our knowledge, our patient represents only the second reported case of such a rare constellation. Even though DNA-methylation-based classification is not yet required for the classification of all CNS tumor types by the 2021 WHO classification of tumors of the CNS, it proved to be crucial to verify the final diagnosis in our patient. In the future, DNA-methylation analysis will most likely become an important asset in neuro-oncological diagnostics and further help to guide treatment strategies in complex or rare clinical cases.

Third Ventricular Subependymomas: Clinical Features and Outcomes Over Two Decades.

BACKGROUND: Subependymomas are uncommon, benign slow-growing neoplasms of the central nervous system preferentially arising within the fourth and lateral ventricles. Third ventricle involvement has been described rarely. The aim of this study is to provide the first systematic review of third ventricular subependymomas (TVSE) by analyzing all reported cases over 2 decades and describing a case example. METHODS: MEDLINE and Embase databases were searched for the 20 years ending January 1, 2022, using relevant MeSH and non-MeSH terms, including "subependymoma" and "third ventricle." Methodology followed PRISMA guidelines. RESULTS: Of 804 identified studies, 131 met inclusion eligibility. The literature yielded 17 patients with TVSE plus our example (18 total). Of these patients, 83% (15/18) presented in adulthood (average age, 42 ± 19 years), of whom 73% were women. The pediatric cohort age was 5 ± 1 years, 67% (4/6) of whom were girls. The most common presenting symptom in both cohorts was headache (80%), followed by memory disturbances and vomitus. In adults, symptomatic tumors were approached by open craniotomy in all but 1 case, most using a transcallosal approach. Gross total resection was obtained in 73%. A ventriculoperitoneal shunt was inserted in 2/15 adult and 4/6 pediatric patients. Overall, both cohorts showed symptomatic improvement without disease recurrence. One patient died perioperatively. CONCLUSIONS: Subependymomas should be considered in the differential diagnosis of third ventricular tumors. The clinical presentation of TVSE mainly parallels hydrocephalus symptoms and, hence, awareness is of vital importance for timely treatment. The surgical goal should be gross total resection, which can be curative and offers greatest clinical improvement across the population.

A Case of Cerebellar Intraparenchymal Subependymoma with Next-Generation Sequencing Analysis.

Subependymomas are rare, intraventricular glial tumors histologically characterized by clusters of small uniform cells distributed in an abundant fibrillary matrix. These tumors can arise in the parenchyma of the cerebrum, cerebellum, or spinal cord. Herein, we report an extremely rare case of cerebellar intraparenchymal subependymoma in a 62-year-old woman. The patient presented with dizziness for several years, and brain magnetic resonance imaging revealed a well-defined solid mass in the right cerebellum, upon which a stereotactic biopsy was performed. Histologically, the tumor showed a distinctive multinodular pattern with unevenly distributed glial cells and an abundant fibrillary matrix. Next-generation sequencing analysis showed balanced genomes without genetic alterations, including single-nucleotide variants, small insertions, deletions, or copy number alterations. Follow-up magnetic resonance imaging revealed that the size of the mass has not changed; the patient has not received any surgical treatments since the pathologic diagnosis and is living healthily.

Survival of patients and risk factors for subependymoma: a population-based study.

OBJECTIVE: Given the paucity of data on the subependymoma, we aimed to evaluate its risk factors from the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: We collected survival and clinical information on patients with subependymoma diagnosed between 1975 and 2016 from the SEER database and screened them according to inclusion and exclusion criteria. Then, univariate and multivariate Cox regression analyses were used to identify significant prognostic factors, and nomograms were constructed to visualize the results. The concordance index (C-index), receiver operating characteristic (ROC), and calibration curves were used to assess the predictive ability of the nomogram. We divided the patient scores into two groups according to the high- and low-risk groups and constructed a survival curve using Kaplan-Meier analysis. RESULTS: A total of 731 patients were initially enrolled, including 511 (69.9%) males and 220 (30.1%) females. After screening, a total of 581 patientswere further evaluated by statistical analysis. The 5- and 10-year survival estimates were 92.0% and 81.9%, respectively. Sex (male, p=0.018; HR=2.3547, 95% CI=1.158-4.788) and age (≥56 years, p<0.001; HR=5.640, 95% CI= 3.139-10.133) were identified as independent prognostic factors for overall survival. The nomogram contained 4 prognostic factors. The C-index was 0.741, and the ROC and calibration curves also indicated the good predictability of the nomogram. CONCLUSION: In this large cohort, a significant association was noted between age/sex and outcome, which could serve an important role for patient education. Even though a significant association was not found between the extent of resection and outcome, the effect of surgery on prognosis should be further explored.Abbreviations: AUC: area under the curve; CI: confidence interval; C-index: concordance index; CNS: central nervous system; GTR: gross total resection; HR: hazard ratio; NOS: not specific; OS: overall survival; PTR: partial resection; ROC: receiver operating characteristic; SEER: Surveillance, Epidemiology, and End Results; STR: subtotal resection; WHO: World Health Organization.