The history of ependymoma management

Review and update on pediatric ependymoma

Since our last Special Annual Issue dedicated to the topic of ependymoma in 2009, critical advancements have been made in the understanding of this disease which is largely confined to childhood. In the era of molecular profiling, the prior classification of ependymoma based on histology has become largely irrelevant, with multiple new subtypes of this disease now being described in the newest 2021 WHO CNS Tumor Classification System. Despite our advancements in understanding the underlying biology of these tumors, the mainstays of treatment-gross total surgical resection followed by confocal radiation therapy-have continued to yield the best treatment results across multiple studies and centers. Here, we provide an update on our understanding of the advancements made in tumor biology, surgical, and oncologic management of this disease. As we move into an era of more personalized medicine, it is critical to reflect on our historical understanding of different disease entities, to better understand the future directions of our treatments.

An Insight into Pathophysiological Features and Therapeutic Advances on Ependymoma

Simple Summary

Although biological information and the molecular classification of ependymoma have been studied, the treatment systems for ependymoma are still insufficient. In addition, because the disease occurs infrequently, it is difficult to obtain sufficient data to conduct large-scale or randomized clinical trials. Therefore, this study is intended to emphasize the importance of understanding its pathological characteristics and prognosis as well as developing treatments for ependymoma through multilateral studies.

Abstract

Glial cells comprise the non-sensory parts of the central nervous system as well as the peripheral nervous system. Glial cells, also known as neuroglia, constitute a significant portion of the mammalian nervous system and can be viewed simply as a matrix of neural cells. Despite being the “Nervenkitt” or “glue of the nerves”, they aptly serve multiple roles, including neuron repair, myelin sheath formation, and cerebrospinal fluid circulation. Ependymal cells are one of four kinds of glial cells that exert distinct functions. Tumorigenesis of a glial cell is termed a glioma, and in the case of an ependymal cell, it is called an ependymoma. Among the various gliomas, an ependymoma in children is one of the more challenging brain tumors to cure. Children are afflicted more severely by ependymal tumors than adults. It has appeared from several surveys that ependymoma comprises approximately six to ten percent of all tumors in children. Presently, the surgical removal of the tumor is considered a standard treatment for ependymomas. It has been conspicuously evident that a combination of irradiation therapy and surgery is much more efficacious in treating ependymomas. The main purpose of this review is to present the importance of both a deep understanding and ongoing research into histopathological features and prognoses of ependymomas to ensure that effective diagnostic methods and treatments can be developed.

Simultaneous cerebrospinal fluid and hematologic metastases in a high-grade ependymoma

Background

Ependymomas are relatively uncommon tumors that constitute about 7% of all primary intracranial neoplasms. Among these, high-grade ependymomas are locally aggressive and recur most commonly at the primary site following resection. Ependymomas are also known to be the one glial neoplasm that tends to frequently metastasize inside and outside the central nervous system (CNS) that complicates workup and management. Metastasis due to surgical manipulation is common and neurosurgeons should be well-versed in the most effective methods to remove these tumors in order to avoid such metastases.

Case Description

Here, we report a case of a 28-year-old female who initially presented with a parenchymal World Health Organization (WHO) grade III anaplastic ependymoma of the occipital lobe without metastasis. After multiple resections, the patient showed no evidence of disease recurrence for 2 years. During follow-up, new metastasis to the frontal lobe as well as to the lung were discovered 2 years after the initial surgery, without recurrence at the tumor's primary site.

Conclusions

While uncommon, this case demonstrates the possibility for ependymomas to metastasize via cerebrospinal fluid to other locations within the CNS and hematologically to extraneural locations without recurring locally.

Review of the History of Non-traumatic Spinal Cord Dysfunction

Background: The incidence of non-traumatic spinal cord dysfunction (SCDys) is reported to be higher than traumatic spinal cord injury (SCI) in many countries. No formal review of the history of SCDys has been published. Objective: This article aims to identify key highlights in the history of SCDys. Method: An electronic literature search was conducted (January 2017) using MEDLINE (1946-2016) and Embase (1974-2016) databases for publications regarding the history of SCDys. Publications on the history of SCI and a selection of neurology textbooks and books on the history of neurology were reviewed for potentially relevant references. The focus of the literature search was on identifying publications that detail key highlights regarding the history of the diagnosis and management of the most common SCDys conditions, as well as those of historical significance. Results: The electronic search of MEDLINE and Embase identified 11 relevant publications. The majority of publications included were identified from the authors' libraries and a selection of books on neurology and the history of neurology. Conclusions: This review outlines the history of SCDys, taking a broader historical perspective and covering the increasing awareness of the role of the spinal cord and knowledge of neuroanatomy. Key milestones in the history of the diagnosis and management of the most common SCDys conditions are presented. An appreciation of the history of SCDys increases our understanding of the large number of people who contributed to our current knowledge of these conditions and in some situations helps guide efforts regarding prevention of SCDys.

Magnetic resonance imaging findings of extraventricular anaplastic ependymoma: A report of 11 cases

Anaplastic ependymomas are rare malignant tumors of the central nervous system. Few studies are available regarding their neuroradiological characteristics. The present study aimed to retrospectively review a series of patients with extraventricular anaplastic ependymoma and to analyze the magnetic resonance imaging (MRI) characteristics to distinguish anaplastic ependymoma from other intracranial tumors. The clinical and pathological images of 11 patients who presented with histologically proven anaplastic ependymoma at Nanfang Hospital (Southern Medical University, Guangzhou, Guangdong, China) between September 2004 and March 2015 were retrospectively reviewed. MRI scans were obtained in all 11 cases. Computed tomography scans were obtained in only 3 cases. In total, 8 tumors were located at the supratentorial parenchyma, and 3 tumors were derived from the cerebellar hemisphere. Images displayed quasi-circular (4/11), irregularly-lobulated (7/11) variable-intensity masses. The masses presented with cysts or necrosis (8/11), hemorrhage (7/11), marked (9/11) or mild (2/11) enhancement, and moderate (4/11), mild (3/11) or absent (4/11) peritumoral edema. The tumors were also frequently closely associated with the lateral ventricle (6/11). Tumors appeared isointense to hypointense on T1-weighted imaging (T1WI) and heterogeneously hyperintense or hypointense on T2WI, demonstrating wreath-like and ring-like characteristics, with intratumoral nodules (3/11) or marked flake-like inhomogeneous (6/11) enhancement on post-contrast MRI. Only 2 solid lesions showed mild enhancement (2/11). Although the MRI features of the extraventricular anaplastic ependymomas varied and were non-specific, these characteristic MRI findings, combined with the locations of the lesions, the age of onset and the short disease course, could be useful in differentiating anaplastic ependymomas from other intracranial neoplasms in the future.

Primary cerebellopontine angle ependymoma with spinal metastasis in an adult patient: A case report

Subtentorial ependymoma is a common central nervous system tumor in young children, but is uncommon in adults. Ependymoma often arises from the cells lining the fourth ventricle. The present study reports a rare case of primary ependymoma that originated from the cerebellopontine angle, with local extension to the two internal auditory canals and remote spinal metastasis, in an adult male. A 50-year-old male presented with headache, tinnitus and bilateral hearing loss that had persisted for 4 months. Magnetic resonance imaging (MRI) revealed a mass in each of the cerebellopontine angles, which had spread to each internal auditory canal and wrapped the VII/VIII cranial nerve complex. A gross total resection was performed to remove the mass in the right side. Histological examination confirmed that the tumor was a World Health Organization grade II papillary ependymoma. Notably, the patient complained of urine retention post-surgery and massive occupational lesions in T3-T4 and L5-S2 were found on full spinal cord MRI. The patient then received combination therapy consisting of temozolomide, and whole-brain and spinal cord radiation. In the final follow-up examination, performed 13 months after treatment, slight shrinkage of the T3 lesion was observed, and no progression of the left cerebellopontine angle and S5-L2 lesions were identified on MRI. In summary, although this clinical entity is rare, the diagnosis of ependymoma and the possibility of spinal cord metastasis should be considered in subtentorial tumors.

Growth-factor-driven rescue to receptor tyrosine kinase (RTK) inhibitors through Akt and Erk phosphorylation in pediatric low grade astrocytoma and ependymoma

Up to now, several clinical studies have been started investigating the relevance of receptor tyrosine kinase (RTK) inhibitors upon progression free survival in various pediatric brain tumors. However, single targeted kinase inhibition failed, possibly due to tumor resistance mechanisms. The present study will extend our previous observations that vascular endothelial growth factor receptor (VEGFR)-2, platelet derived growth factor receptor (PDGFR)β, Src, the epidermal growth factor receptor (ErbB) family, and hepatocyte growth factor receptor (HGFR/cMet) are potentially drugable targets in pediatric low grade astrocytoma and ependymoma with investigations concerning growth-factor-driven rescue. This was investigated in pediatric low grade astrocytoma and ependymoma cell lines treated with receptor tyrosine kinase (RTK) inhibitors e.g. sorafenib, dasatinib, canertinib and crizotinib. Flow cytometry analyses showed high percentage of cells expressing VEGFR-1, fibroblast growth factor receptor (FGFR)-1, ErbB1/EGFR, HGFR and recepteur d’origine nantais (RON) (respectively 52-77%, 34-51%, 63-90%, 83-98%, 65-95%). Their respective inhibitors induced decrease of cell viability, measured with WST-1 cell viability assays. At least this was partially due to increased apoptotic levels measured by Annexin V/Propidium Iodide apoptosis assays. EGF, HGF and FGF, which are normally expressed in brain (tumor) tissue, showed to be effective rescue inducing growth factors resulting in increased cell survival especially during treatment with dasatinib (complete rescue) or sorafenib (partial rescue). Growth-factor-driven rescue was less prominent when canertinib or crizotinib were used. Rescue was underscored by significantly activating downstream Akt and/or Erk phosphorylation and increased tumor cell migration. Combination treatment showed to be able to overcome the growth-factor-driven rescue. In conclusion, our study highlights the extensive importance of environmentally present growth factors in developing tumor escape towards RTK inhibitors in pediatric low grade astrocytoma and ependymoma. It is of great interest to anticipate upon these results for the design of new therapeutic trials with RTK inhibitors in these pediatric brain tumors.

Telomerase inhibition abolishes the tumorigenicity of pediatric ependymoma tumor-initiating cells

Pediatric ependymomas are highly recurrent tumors resistant to conventional chemotherapy. Telomerase, a ribonucleoprotein critical in permitting limitless replication, has been found to be critically important for the maintenance of tumor-initiating cells (TICs). These TICs are chemoresistant, repopulate the tumor from which they are identified, and are drivers of recurrence in numerous cancers. In this study, telomerase enzymatic activity was directly measured and inhibited to assess the therapeutic potential of targeting telomerase. Telomerase repeat amplification protocol (TRAP) (n = 36) and C-circle assay/telomere FISH/ATRX staining (n = 76) were performed on primary ependymomas to determine the prevalence and prognostic potential of telomerase activity or alternative lengthening of telomeres (ALT) as telomere maintenance mechanisms, respectively. Imetelstat, a phase 2 telomerase inhibitor, was used to elucidate the effect of telomerase inhibition on proliferation and tumorigenicity in established cell lines (BXD-1425EPN, R254), a primary TIC line (E520) and xenograft models of pediatric ependymoma. Over 60 % of pediatric ependymomas were found to rely on telomerase activity to maintain telomeres, while no ependymomas showed evidence of ALT. Children with telomerase-active tumors had reduced 5-year progression-free survival (29 ± 11 vs 64 ± 18 %; p = 0.03) and overall survival (58 ± 12 vs 83 ± 15 %; p = 0.05) rates compared to those with tumors lacking telomerase activity. Imetelstat inhibited proliferation and self-renewal by shortening telomeres and inducing senescence in vitro. In vivo, Imetelstat significantly reduced subcutaneous xenograft growth by 40 % (p = 0.03) and completely abolished the tumorigenicity of pediatric ependymoma TICs in an orthotopic xenograft model. Telomerase inhibition represents a promising therapeutic approach for telomerase-active pediatric ependymomas found to characterize high-risk ependymomas.

A retrospective analysis of recurrent intracranial ependymoma

BACKGROUND

Recurrence occurs in almost 50% of patients with intracranial ependymoma, and their outcome following recurrence is poor.

METHODS

We retrospectively reviewed the medical records of 22 patients with intracranial ependymoma and subsequent relapse(s) (59 recurrences) treated at Children's Hospital Los Angeles or New York University between January 1997 and December 2012.

RESULTS

Median duration of follow-up was 52 months (7-171 months). Median age at initial diagnosis was 4 years (0.3-19 years) with 8 patients younger than 3 years at presentation. Eleven patients had anaplastic and 11 cellular pathologies. Eighteen patients had infratentorial tumors at diagnosis and 3 (all infratentorial) had metastatic spinal cord involvement at presentation. Cerebrospinal fluid involvement was not identified at diagnosis or relapse. Median time to first recurrence was 16 months (1.3 to 115 months). The number of recurrences in each patient ranged from 1 to 9 (median = 2). Thirty-seven recurrences (63%) were detected asymptomatically by surveillance imaging. Fifteen recurrences (26%) arose outside the initial tumor site. Recurrences were treated by surgical resection (45), with irradiation (30), and with various oral chemotherapies (23) with (7) or without (16) conventional chemotherapy. The 5 and 10 year overall survival rates from first recurrence were 0.37 ± 0.14 and 0.25 ± 0.14.

CONCLUSION

Prolonged (5-10 year) survival from first relapse was noted in over one-quarter of our patients. It remains unclear whether early radiographic diagnosis, differing treatment modalities beyond radical surgical resection or possibly unrecognized biological differences contributed towards this prolonged survival.

Spinal cord ependymoma associated with neurofibromatosis 1 : case report and review of the literature

Patients with neurofibromatosis 1 (NF1) are predisposed to develop central nervous system tumors, due to the loss of neurofibromin, an inactivator of proto-oncogene Ras. However, to our knowledge, only three cases of ependymomas with NF1 have been reported in the literature. The authors present a case of NF1 patient with a spinal cord ependymoma. She was referred for about half a year history of increasing numbness that progressed from her fingers to her entire body above the bellybutton. Magnetic resonance imaging revealed a relative-demarcated, heterogeneously enhanced mass lesion accompanied by perifocal edema in C5-7 level, a left-sided T11 spinous process heterogeneously enhanced mass in soft tissue, intervertebral disk hernia in L2-5 level, and widespread punctum enhancing lesion in her scalp and in T11-L5 level. The patient underwent C5-7 laminectomies and total excision of the tumor under operative microscope, and intraoperative ultrasonography and physiological monitoring were used during the surgery. Histopathologically, her tumor was found to be a ependymoma without malignant features (grade II in the World Health Organization classification). Therefore, no adjuvant therapy was applied. Following the operation, the patient showed an uneventful clinical recovery with no evidence of tumor recurrence after one year of follow-up.

Fourth ventricular ependymoma with a distant intraventricular metastasis: Report of a rare case

Ependymoma is one of the uncommon tumors of the central nervous system (CNS) in the adult age group. These tumors have a distinct propensity for metastasis, both within and outside the CNS. However, dissemination at the time of first presentation and retrograde dissemination of the tumor is rare. We report the case of a patient with fourth ventricular anaplastic ependymoma who presented with left lateral ventricular metastasis which was anatomically different from the primary tumor. We describe the clinic-pathological detail of the patient and discuss the probable pathophysiological basis for this rare presentation and its significance in management of the patient.

Intracranial ependymoma: long-term results in a series of 21 patients treated with stereotactic (125)iodine brachytherapy

Background

We evaluated the long-term outcome in patients harboring intracranial ependymomas treated with interstitial brachytherapy (IBT).

Methods

Twenty-one patients (M/F = 9/12; median age: 29 years; range: 8–70 years), diagnosed with intracranial ependymoma (1 WHO I, 11 WHO II, 9 WHO III) were treated with IBT using stereotactically implanted ¹²⁵Iodine seeds between 1987 and 2010, either primarily, as adjuvant therapy following incomplete resection, or as salvage treatment upon tumor recurrence. Sixteen of 21 patients underwent microsurgical resection prior to IBT; in 5 patients, IBT was performed primarily after stereotactic biopsy for histological diagnosis. The cumulative tumor surface dose ranged from 50–65 Gy treating a median tumor volume of 3.6 ml (range, 0.3–11.6 ml). A median follow-up period of 105.3 months (range, 12.7–286.2 months) was evaluated.

Results

Actuarial 2-, 5- and 10-years overall- and disease-specific survival rates after IBT were each 90% and 100% at all times for ependymomas WHO I/II, for anaplastic ependymomas WHO III 100%, 100%, 70% and 100%, 100%, 86%, respectively. The neurological status of seven patients improved, while there was no change in 12 and deterioration in 2 patients, respectively. Follow-up MR images disclosed a complete tumor remission in 3, a partial remission in 12 and a stable disease in 6 patients. Treatment-associated morbidity only occurred in a single patient.

Conclusions

This study shows that stereotactic IBT for intracranial ependymomas is safe and can provide a high degree of local tumor control. Due to the low rate of side effects, IBT may evolve into an attractive alternative to microsurgery in ependymomas located in eloquent areas or as a salvage treatment.

Prognostic factors and treatment options for paediatric ependymomas

The aim of this study was to determine factors of prognostic relevance for paediatric ependymomas, and evaluate the efficacy of treatment modalities. This is a retrospective study of 43 patients with ependymoma (<18 years) who underwent a combination of surgical excision, chemotherapy, and/or radiotherapy treatment at The Prince of Wales Cancer Centre between 1969 and 2009. Statistical analysis was performed to assess the prognostic relevance of various parameters affecting the two-year and five-year overall survival (OS) and progression-free survival (PFS). The five-year OS and PFS were 50.3% and 44.8% respectively (median follow-up 50 months). Eighteen patients (41.9%) experienced tumour recurrence: 13 had a local recurrence (LR) and five had both LR and distant recurrence. On univariate analysis, a more favourable prognosis in terms of both OS and PFS was evident for supratentorial tumours compared to infratentorial tumours (OS p=0.007, PFS p=0.045), stereotactic radiosurgery/ fractionated stereotactic radiotherapy compared to craniospinal irradiation or local posterior fossa/local brain±boost radiotherapy modalities (OS p=0.047, PFS p=0.031), total radiotherapy dose >50 Gy compared to ≤50 Gy (OS p=0.008, PFS p=0.005), and in patients with no tumour recurrence compared to those with recurrence (OS p=0.03, PFS p<0.001). Although not statistically significant, a more favourable multivariate outcome was evident in patients who underwent complete surgical resection. Chemotherapy treatment and histopathological grade, however, were not relevant to prognosis. This study supports the need to pursue more aggressive treatment for infratentorial and/or recurrent tumours. Ideal treatment involves maximal surgical resection, followed by adjuvant radiotherapy (>50 Gy).

Long-term survival following gross total resection of pediatric supratentorial ependymomas without adjuvant therapy

Pediatric supratentorial ependymoma is very rare. In pediatric patients with supratentorial ependymoma, surgery alone may be an acceptable treatment when postoperative imaging confirms a gross total resection. Surgical resection is the standard and the most important treatment for ependymoma. The role of radiation therapy and/or chemotherapy following a gross total resection of supratentorial ependymoma has been uncertain. We report 2 cases of pediatric supratentorial ependymomas treated by gross total resection without postoperative adjuvant therapy. The first patient was a 7-year-old girl who presented with motor weakness and a hemiconvulsion of the right leg. Magnetic resonance imaging (MRI) revealed a large heterogeneously enhanced tumor in the left frontal lobe. The second patient was an 8-year-old girl who presented with headache. MRI revealed a huge heterogeneously enhanced tumor in the left frontal lobe. Gross total resection was achieved in both patients. Postoperative radiotherapy and chemotherapy were avoided following gross total resection. Histologically, the lesions demonstrated grade II ependymoma and anaplastic ependymoma, respectively. After follow-up of 120 months, neither patient had recurrence or dissemination. These results suggest that patients with pediatric supratentorial ependymoma treated by gross total resection alone have a favorable outcome, and postoperative radiotherapy and chemotherapy may be avoided.

17-year-old girl with headache and complex partial seizure

Supratentorial cortical ependymoma is a rare clinical entity where ependymoma occurring in the cortex without any connection to the ventricular system since ependymoma usually arises from the lining of the ventricular system or central canal of spinal cord. There have been 14 such cases reported in the literature.We report the first case of a supratentorial extraaxial cortical anaplastic ependymoma with minimal cortical attachment in a 17-years-old girl, presented with headache and complex partial seizure. Histological features of anaplasia including numerous mitoses, necrosis and high Ki-67 lead to postoperative adjuvant radiation therapy although gross total resection was achieved.

Nervous system tumors in adult immigrants to Sweden by subsite and histology

BACKGROUND

The coding of histology of nervous system (NS) tumors with various degrees of malignancies differs between cancer registries, whereby the comparison of incidence rates from one registry to another seems difficult. No study has systematically defined whether the change in the risk of NS tumors upon immigration in adulthood varies by subsite or histology. Therefore, we aimed to address this issue amongst the first-generation immigrants to Sweden based on a large uniform cancer registry data (1958-2006).

METHODS

The nationwide Swedish Family-Cancer Database (2008 version; >11.8 million individuals; 1.8 million immigrants; histology code in force since 1958) was used to calculate standardized incidence ratios (SIRs). We analyzed 28,981 adult cases of NS tumors amongst Swedes and 2519 amongst immigrants (age ≥ 30).

RESULTS

Significantly decreased risks for brain glioma were amongst German (SIR = 0.64), Eastern European (0.62), some Asian (0.71), Chilean (0.34), and African immigrants (0.52). We found an increased risk for brain meningioma amongst Finns (1.15) and former Yugoslavians (1.33), whilst only Norwegians (0.71) and Latin Americans (0.21) had a decreased risk. The risk for spinal ependymoma and astrocytoma was increased in Germans (3.66) and former Yugoslavians (8.89). We found no significant difference for peripheral nerve tumors between immigrants and the native Swedes.

CONCLUSION

Significant differences between risk of NS tumors amongst immigrants and the native Swedes may suggest different risk factor profiles for glioma compared to meningioma indicating a higher etiological role of genetic background or childhood environmental risk factors rather than exposures after immigration.

P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2) localize in the microvessels forming the blood-tumor barrier in ependymomas

Ependymomas are neuroepithelial tumors that arise from the ependymal layer bordering the cerebral ventricles and spinal canal. Intracranial ependymoma represents a major encephalic tumor in children, while spinal ependymoma develops more frequently in adults. To understand the pharmacoresistance that characterizes this tumoral entity, we analyzed the level of expression and localization of three major efflux transport proteins with a multidrug resistance function, P-glycoprotein, multidrug resistance-related protein 1 (MRP1) and breast cancer resistance protein (BCRP), in a series of 25 ependymomas from both children and adults. Real-time-PCR analysis showed that all three genes were expressed in all tumors, with no apparent correlation between the level of expression and either age or tumor grade. The MRP1 transcript was expressed at a significantly higher level in spinal tumors than in intracranial tumors. The expression of the proteins corresponding to these genes was confirmed by Western blot analysis. In an immunohistochemical study, P-glycoprotein and BCRP were shown to be associated with the tumoral vessels, where they presented a luminal localization, a prerequisite for their efflux drug activity into the blood. These data indicate that a biochemical, transporter-dependent blood-tumor barrier may exist in ependymomas, which may reduce the tumoral bioavailability of lipophilic and amphiphilic anticancer drugs.