Genome-wide analysis of subependymomas shows underlying chromosomal copy number changes involving chromosomes 6, 7, 8 and 14 in a proportion of cases

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.

Clinical independent prognostic factors and overall survival prognostic nomogram for intracranial subependymoma: A SEER population-based analysis 2004–2016

Purpose

This study was launched to ascertain the independent prognostic factors influencing the overall survival (OS) prognosis of intracranial subependymoma and construct a prognostic model to predict OS time.

Materials and methods

We collected data from patients with intracranial subependymoma, including treatment data, follow-up data, and clinical and pathological characteristics from the SEER database within 2004 to 2016, and patients were randomly classified into training and validation cohorts. Univariate and multivariate analyses were applied to the training group through building a Cox proportional hazards model. According to the results of multivariate analysis, we established a nomogram to forecast the OS rate of the per-case patient graphically, then calculated the accuracy of verification in both training and validation cohorts by concordance index (C-index). Univariate and multivariate analyses were used for different subgroups of unoperated versus operated, gross total resection (GTR), subtotal resection (STR), and biopsy after using the propensity score matching (PSM) analyses.

Results

A total of 667 patients were enrolled, and we randomly assigned 535 patients (80.21%) into the training cohort and 132 patients (19.79%) into the validation cohort. Age [hazard ratio (HR) = 6.355; 95% confidence interval (CI), 2.240–18.029; p = 0.001] and sex (HR = 0.475; 95% CI, 0.232–0.974; p = 0.042) were the independent prognostic factors in the training cohort. On the basis of age and sex, the nomogram was established to predict the OS for every patient (C-index = 0.733 ± 0.065 in the training cohort and 0.850 ± 0.065 in the validation cohort), and calibration plots reflected the reliability of the nomogram. Age, gender, or laterality was the independent prognostic factor for OS in the different matched subgroups of unoperated versus operated, GTR, STR, and biopsy. Surgical treatment, race, year of diagnosis, insurance, tumor location, tumor size, pathology, tumor grade, and radiation were not statistically significantly different in OS for subependymoma in our research.

Conclusion

Age and sex were the independent prognostic variables for OS in intracranial subependymoma. According to our research, we should not be more inclined to choose conservative or surgical treatment. Nonetheless, the information that we present might be useful to suggest potential hypotheses to be tested in the clinical research setting.

Intraparenchymal subependymoma: Case report and literature review

Background:

Intracranial subependymomas are rare slow-growing benign tumors typically located in the ventricular system, accounting for 0.07–0.7% of all intracranial neoplasms. Intraparenchymal subependymoma is extremely rare lesions, imposing a challenging diagnosis and management.

Case Description:

We describe a case of a supratentorial intraparenchymal mass on left occipital lobe in a 26-year-old woman with progressive headache and visual impairment. Differential diagnosis mainly included gliomas, neuronal-glial tumors, ependymoma, and subependymoma. Complete surgical resection was performed and histopathology analysis confirmed diagnosis of subependymoma. Despite its benign behavior the Ki67/MIB-1 labeling index assessed by immunohistochemistry was 5%. After 1 year of follow-up she was free of tumor recurrence.

Conclusion:

Intraparenchymal subependymoma is extremely rare tumors and literature review showed only 11 cases reported. In general, they are misdiagnosed as other tumors, so careful attention on clinical and radiological features must be taken when looking at a tumor close to the ventricular system, even though it does not have any obvious direct connection to it. Despite its benign nature, total removal must be attempted given that there are reports of recurrence, especially in partially removed tumors with high proliferation index. The role of adjuvant therapy is still limited and new treatment options are being developed as our knowledge on biological and molecular characteristics advances.

Subependymoma involving multiple spinal cord levels: A clinicopathological case series with chromosomal microarray analysis

Subependymomas of the spinal cord are rare, do not often involve multiple levels, and very rarely recur. Here, we present a series of spinal cord subependymomas with a detailed description of the clinical, radiological and pathological features, and characterization by chromosomal microarray analysis. Briefly, the four patients included two men and two women, between the ages of 22 and 48 years. The most common presenting symptoms were neck and arm pain with upper extremity weakness. By imaging, the tumors were found to involve multiple spinal levels, including cervical/ cervico-thoracic (three patients) and thoracic (one patient), were all eccentric, and had minimal to no post-contrast enhancement. Two patients underwent gross total resection, one had a sub-total resection, and one underwent biopsy alone with a decompressive laminectomy. Follow up ranged from 6 months to 22 years. One patient (case 4) had recurrence 15 years following gross total resection and chromosomal microarray analysis revealed deletions on the long arm of chromosome 6. Our limited series suggests that spinal cord subependymomas can rarely recur, even following gross total resection, suggesting a possible role for long-term surveillance for these rare tumors.

Diagnostics of pediatric supratentorial RELA ependymomas: integration of information from histopathology, genetics, DNA methylation and imaging

Ependymoma with RELA fusion has been defined as a novel entity of the revised World Health Organization 2016 classification of tumors of the central nervous system (CNS), characterized by fusion transcripts of the RELA gene and consequent pathological activation of the NFkB pathway. These tumors represent the majority of supratentorial ependymomas in children. The validation of diagnostic tools to identify this clinically relevant ependymoma entity is essential. Here, we have used interphase fluorescent in situ hybridization (FISH) for C11orf95 and RELA, immunohistochemistry (IHC) for p65‐RelA and the recently developed DNA methylation‐based classification besides conventional histopathology, and compared the precision of the methods in 40 supratentorial pediatric brain tumors diagnosed as ependymomas in the past years. Reverse transcription PCR (RT‐PCR) and RNA sequencing were performed to explore discordant cases. Furthermore, we integrated imaging and clinical features as additional layers of information. The concordance between nuclear RelA expression by IHC and RELA FISH was 100%. Concordance between IHC and DNA methylation profiling, and between FISH and DNA methylation profiling was also high (96.4% and 95.2%, respectively). Thirty‐four out of 40 (85%) cases were confirmed by integrated diagnoses as ependymal tumors, including 22 RELA‐fused ependymomas (71% of ependymal tumors), two YAP1‐fused ependymomas (6%), six non‐RELA/non‐YAP1 ependymomas (18%) and four ependymal/subependymal mixed tumors (12%). Ependymal/subependymal mixed tumors had an excellent clinical outcome despite the presence of histopathological signs of malignancy, suggesting that these tumors should not be diagnosed as classic ependymomas. DNA methylation profiling helped in the differential diagnosis of RELA‐fused ependymomas. IHC and FISH, which are available in the majority of pathology laboratories, are valuable tools to identify RELA‐fused ependymomas.

Molecular Classification of Ependymal Tumors across All CNS Compartments, Histopathological Grades, and Age Groups

Ependymal tumors across age groups are currently classified and graded solely by histopathology. It is, however, commonly accepted that this classification scheme has limited clinical utility based on its lack of reproducibility in predicting patients' outcome. We aimed at establishing a uniform molecular classification using DNA methylation profiling. Nine molecular subgroups were identified in a large cohort of 500 tumors, 3 in each anatomical compartment of the CNS, spine, posterior fossa, supratentorial. Two supratentorial subgroups are characterized by prototypic fusion genes involving RELA and YAP1, respectively. Regarding clinical associations, the molecular classification proposed herein outperforms the current histopathological classification and thus might serve as a basis for the next World Health Organization classification of CNS tumors.

Subependymoma: clinical features and surgical outcomes

OBJECTIVE

Subependymomas are rare, indolent neoplasms that have been described in the brain and the spinal cord. The purpose of this study is to report the clinical and radiolographic features, and surgical outcomes of this entity.

METHODS

Twenty-six patients with pathologically-verified subependymomas were treated from 1990 through 2009, with a mean follow-up of 39 months. The clinical and radiological records were reviewed and outcomes analyzed.

RESULTS

There were 15 fourth ventricle tumors, 6 lateral ventricle tumors, and 5 spinal tumors. For the intracranial tumors, headaches, changes in vision, and difficulties with balance were the most common symptoms. Most tumors were heterogeneously enhancing and hypointense or isointense to gray matter on T1-imaging and hyperintense on T2-imaging. All patients with tumors in the fourth ventricle underwent a suboccipital craniotomy and seven patients received an additional C1 laminectomy. Patients with lateral ventricular tumors underwent craniotomy with primarily a transcallosal resection. Patients with spinal tumors underwent laminectomy with intramedullary tumor resection. All tumors were resected employing microsurgical techniques. Overall, six patients had a sub-total resection. No recurrence of tumor or symptoms was noted at last follow-up for any patient, suggesting that maximal safe resection is often sufficient to provide symptomatic relief. Three patients had long-term complications from surgery. Tumor location was not associated with age at presentation, resection achieved, or development of complications.

CONCLUSIONS

Subependymomas are indolent tumors that when symptomatic can present with cerebrospinal fluid (CSF) obstructive symptoms in the brain and myelopathy in the spinal cord. There is no one symptom diagnostic for subependymomas. Surgical treatment can provide long term tumor control.

Surgical management of intracranial subependymomas

BACKGROUND

Intracranial subependymomas are rare, slow-growing and usually non-invasive tumors. The aim of this study was to analyze our experience with the surgical treatment of intracranial subependymomas.

METHODS

Between 1991 and 2007, 11 patients with intracranial subependymomas had surgery in our institution. Mean age of the patients was 54.4 years (ranging from 40 to 85 years).

RESULTS

Tumors were located in the fourth ventricle in seven patients and in the lateral ventricle in four patients. Most patients presented with symptoms related to intracranial hypertension and/or cerebellar signs and symptoms (headache: eight patients; dizziness: six patients; nausea: six patients; gait ataxia: four patients), one patient with cognitive decline and flattened affect, and one patient with a hemiparesis. Six patients presented with hydrocephalus, but only one needed a permanent cerebrospinal fluid (CSF) shunt. Complete removal of the tumor was possible in eight cases. Following surgery, only one patient experienced a permanent drop of his Karnofsky Performance Index (from 70 to 60). Median follow-up was 37 months. There were no true recurrences during follow-up. A second surgery was required 7 years after the first operation for progression of an incompletely resected tumor.

CONCLUSIONS

Removal of symptomatic subependymomas can be performed safely. Prognosis is excellent after a complete resection. The potential for a surgical cure, low surgical complication rates and the risk of undertreatment of a more aggressive tumor together may justify surgery for asymptomatic lesions.