Myxopapillary ependymomas in children: imaging, treatment and outcomes

Pediatric-Like Brain Tumors in Adults

Pediatric brain tumors are different to those found in adults in pathological type, anatomical site, molecular signature, and probable tumor drivers. Although these tumors usually occur in childhood, they also rarely present in adult patients, either as a de novo diagnosis or as a delayed recurrence of a pediatric tumor in the setting of a patient that has transitioned into adult services.Due to the rarity of pediatric-like tumors in adults, the literature on these tumor types in adults is often limited to small case series, and treatment decisions are often based on the management plans taken from pediatric studies. However, the biology of these tumors is often different from the same tumors found in children. Likewise, adult patients are often unable to tolerate the side effects of the aggressive treatments used in children-for which there is little or no evidence of efficacy in adults. In this chapter, we review the literature and summarize the clinical, pathological, molecular profile, and response to treatment for the following pediatric tumor types-medulloblastoma, ependymoma, craniopharyngioma, pilocytic astrocytoma, subependymal giant cell astrocytoma, germ cell tumors, choroid plexus tumors, midline glioma, and pleomorphic xanthoastrocytoma-with emphasis on the differences to the adult population.

Ependymoma from Benign to Highly Aggressive Diseases: A Review

Ependymomas comprise biologically distinct tumor types with respect to age distribution, (epi)genetics, localization, and prognosis. Multimodal risk-stratification, including histopathological and molecular features, is essential in these biologically defined tumor types. Gross total resection (GTR), achieved with intraoperative monitoring and neuronavigation, and if necessary, second-look surgery, is the most effective treatment. Adjuvant radiation therapy is mandatory in high-risk tumors and in case of residual tumor. There is yet growing evidence that some ependymal tumors may be cured by surgery alone. To date, the role of chemotherapy is unclear and subject of current studies.Even though standard therapy can achieve reasonable survival rates for the majority of ependymoma patients, long-term follow-up still reveals a high probability of relapse in certain biological entities.With increasing knowledge of biologically distinct tumor types, risk-adapted adjuvant therapy gains importance. Beyond initial tumor control, and avoidance of therapy-induced morbidity for low-risk patients, intensified treatment for high-risk patients comprises another challenge. With identification of specific risk features regarding molecular alterations, targeted therapy may represent an option for individualized treatment modalities in the future.

Multi-institutional Characterization of Outcomes for Pediatric and Young Adult Patients With High-Risk Myxopapillary Ependymoma After Radiation Therapy

PURPOSE

Myxopapillary ependymoma (MPE) is a rare, typically slow-growing subtype of spinal ependymomas. There are no standard guidelines for radiotherapy and long-term outcomes after radiation, particularly patterns of relapse, for pediatric and young adult (YA) patients with MPE remain under-characterized.

METHODS AND MATERIALS

This is an Institutional Review Board-approved multi-institutional retrospective cohort study of 60 pediatric and YA patients diagnosed with MPE and received radiotherapy between 2000-2020. Clinical and treatment characteristics, and long-term outcomes were recorded. Site(s) of progression was compared to radiation fields. Survival outcomes were analyzed using Kaplan-Meier method. Cumulative incidence of local in-field progression (CILP) after initial radiotherapy was analyzed using Gray's method with out-of-field-only progression as a competing risk. Univariate analyses were performed using Cox proportional hazard's model.

RESULTS

The median age at radiation was 14.8 years (range: 7.1-26.5). At time of radiotherapy, 45 (75.0%) and 35 (58.3%) patients had gross residual and multifocal disease, respectively. Forty-eight (80.0%), seven (11.7%) and five (8.3%) patients received involved field radiotherapy, craniospinal irradiation, and whole spine radiation, respectively. Median follow-up from end of radiotherapy was 6.2 years (range: 0.6-21.0). Five-year overall survival, progression-free survival, and CILP were 100%, 60.8% and 4.1%, respectively. Both local recurrences were at sites of gross residual disease. Of the eighteen out-of-field first recurrences after radiotherapy, all were superior to the initial treatment field and nine had intracranial relapse. On univariate analyses, distant-only recurrence before radiation (HR: 4.00, 95% CI: 1.54-10.43, p = 0.005) was significantly associated with shorter time to progression.

CONCLUSIONS

While the risk of recurrence within the radiation field is low, pediatric and YA patients with high-risk MPE remain at risk for recurrences in the spine above the radiation field and intracranially after radiotherapy. Future prospective studies are needed to investigate the appropriate radiation field and dose based on the extent of metastases.

A Radiologist's Guide to the 2021 WHO Central Nervous System Tumor Classification: Part 2-Newly Described and Revised Tumor Types

The fifth edition of the World Health Organization classification of tumors of the central nervous system (CNS), published in 2021, introduces major shifts in the classification of brain and spine tumors. These changes were necessitated by rapidly increasing knowledge of CNS tumor biology and therapies, much of which is based on molecular methods in tumor diagnosis. The growing complexity of CNS tumor genetics has required reorganization of tumor groups and acknowledgment of new tumor entities. For radiologists interpreting neuroimaging studies, proficiency with these updates is critical in providing excellent patient care. This review will focus on new or revised CNS tumor types and subtypes, beyond infiltrating glioma (described in part 1 of this series), with an emphasis on imaging features.

Major Features of the 2021 WHO Classification of CNS Tumors

Advances in the understanding of the molecular biology of central nervous system (CNS) tumors prompted a new World Health Organization (WHO) classification scheme in 2021, only 5 years after the prior iteration. The 2016 version was the first to include specific molecular alterations in the diagnoses of a few tumors, but the 2021 system greatly expanded this approach, with over 40 tumor types and subtypes now being defined by their key molecular features. Many tumors have also been reconceptualized into new "supercategories," including adult-type diffuse gliomas, pediatric-type diffuse low- and high-grade gliomas, and circumscribed astrocytic gliomas. Some entirely new tumors are in this scheme, particularly pediatric tumors. Naturally, these changes will impact how CNS tumor patients are diagnosed and treated, including clinical trial enrollment. This review addresses the most clinically relevant changes in the 2021 WHO book, including diffuse and circumscribed gliomas, ependymomas, embryonal tumors, and meningiomas.

Extra-Neural Metastases of Late Recurrent Myxopapillary Ependymoma to Left Lumbar Paravertebral Muscles: Case Report and Review of the Literature

Ependymomas are commonly classified as low-grade tumors, although they may harbor a malignant behavior characterized by distant neural dissemination and spinal drop metastasis. Extra-CNS ependymoma metastases are extremely rare and only few cases have been reported in the lung, lymph nodes, pleura, mediastinum, liver, bone, and diaphragmatic, abdominal, and pelvic muscles. A review of the literature yielded 14 other case reports metastasizing outside the central nervous system, but to our knowledge, no studies describe metastasis in the paravertebral muscles. Herein, we report the case of a 39-year-old patient with a paraspinal muscles metastasis from a myxopapillary ependymoma. The neoplasm was surgically excised and histologically and molecularly analyzed. Both the analyses were consistent with the diagnosis of muscle metastases of myxopapillary ependymoma. The here-presented case report is first case in the literature of a paraspinal muscles metastasis of myxopapillary ependymoma.

Clinical implications of the 2021 edition of the WHO classification of central nervous system tumours

A new edition of the WHO classification of tumours of the CNS was published in 2021. Although the previous edition of this classification was published just 5 years earlier, in 2016, rapid advances in our understanding of the molecular underpinnings of CNS tumours, including the diversity of clinically relevant molecular types and subtypes, necessitated a new classification system. Compared with the 2016 scheme, the new classification incorporates even more molecular alterations into the diagnosis of many tumours and reorganizes gliomas into adult-type diffuse gliomas, paediatric-type diffuse low-grade and high-grade gliomas, circumscribed astrocytic gliomas, and ependymal tumours. A number of new entities are incorporated into the 2021 classification, especially tumours that preferentially or exclusively arise in the paediatric population. Such a substantial revision of the WHO scheme will have major implications for the diagnosis and treatment of patients with CNS tumours. In this Perspective, we summarize the main changes in the classification of diffuse and circumscribed gliomas, ependymomas, embryonal tumours and meningiomas, and discuss how each change will influence post-surgical treatment, clinical trial enrolment and cooperative studies. Although the 2021 WHO classification of CNS tumours is a major conceptual advance, its implementation on a routine clinical basis presents some challenges that will require innovative solutions.

Resection of disseminated recurrent myxopapillary ependymoma with more than 4-year follow-up: operative nuance for prolonged prone position. Illustrative case

BACKGROUND

Symptomatic disseminated myxopapillary ependymoma (MPE) in a young person presents a daunting challenge because the risks of prolonged prone positioning and spinal cord injury may outweigh the likelihood of attaining the benefit of gross total resection.

OBSERVATIONS

The authors reported the case of a 15-year-old girl with five discrete recurrent spinal cord ependymomas. The patient received a 25-hour surgical procedure for gross total resection of the tumors and fusion over an approximately 33-hour period. She experienced complete resolution of all preoperative neurological symptoms and subsequently received adjuvant radiation therapy. At 52 months after surgery, she was still experiencing neurologically intact, progression-free survival. This case illustrated one of the most extensive recurrent tumor resections for MPE with prolonged disease-free survival reported to date. It may also represent the longest prone position spinal case reported and was notable for a lack of any of the complications commonly associated with the prolonged prone position.

LESSONS

The authors discussed the complexity of surgical decision-making in a symptomatic patient with multiple disseminated metastases, technical considerations for resection of intradural and intramedullary spinal cord tumors, and considerations for avoiding complications during prolonged positioning necessary for spinal surgery.

Ependymoma: Evaluation and Management Updates

PURPOSE OF REVIEW

To review state of art and relevant advances in the molecular genetics and management of ependymomas of children and adults.

RECENT FINDINGS

Ependymomas may occur either in the brain or in the spinal cord. Compared with intracranial ependymomas, spinal ependymomas are less frequent and exhibit a better prognosis. The new WHO classification of CNS tumors of 2021 has subdivided ependymomas into different histomolecular subgroups with different outcome. The majority of studies have shown a major impact of extent of resection; thus, a complete resection must be performed, whenever possible, at first surgery or at reoperation. Conformal radiotherapy is recommended for grade 3 or incompletely resected grade II tumors. Proton therapy is increasingly employed especially in children to reduce the risk of neurocognitive and endocrine sequelae. Craniospinal irradiation is reserved for metastatic disease. Chemotherapy is not useful as primary treatment and is commonly employed as salvage treatment for patients failing surgery and radiotherapy. Standard treatments are still the mainstay of treatment: the discovery of new druggable pathways will hopefully increase the therapeutic armamentarium in the near future.

Pediatric spinal intramedullary anaplastic myxopapillary ependymoma: a case report

A 6-year-old girl presented with a 1-week history of progressive upper and lower extremity weakness and bilateral upper extremity dysesthesia. Imaging demonstrated a 4.7 × 1.2-cm enhancing intramedullary lesion in the cervical spine from level C2 to C5 with associated cystic components and syringomyelia. The patient underwent a C2-C5 laminoplasty, with gross total resection of the intramedullary lesion. Histological analysis showed small to medium-sized epithelioid cells, with predominantly a solid architecture focally infiltrating into the adjacent spinal cord tissue. Focal papillary differentiation was present along with peri-vascular pseudorosettes, mucin microcysts, and globules of dense collagen. Focal anaplasia was noted with mitosis (5/10 HPF), focal necrosis, and elevated Ki67 10-15%. These findings were consistent with a myxopapillary ependymoma with anaplastic features. CSF cytology was negative for tumor cells. MYCN amplification was not present. She was treated with targeted proton-beam radiation therapy. This is the fourth case of an intramedullary anaplastic myxopapillary ependymoma to date, and the first case in the cervical spine reported in the literature.

Childhood Malignant Brain Tumors: Balancing the Bench and Bedside

Simple Summary

Brain tumors remain the most common childhood solid tumors, accounting for approximately 25% of all pediatric cancers. They also represent the most common cause of cancer-related illness and death in this age group. Recent years have witnessed an evolution in our understanding of the biological underpinnings of many childhood brain tumors, potentially improving survival through both improved risk group allocation for patients to provide appropriate treatment intensity, and novel therapeutic breakthroughs. This review aims to summarize the molecular landscape, current trial-based standards of care, novel treatments being explored and future challenges for the three most common childhood malignant brain tumors—medulloblastomas, high-grade gliomas and ependymomas.

Abstract

Brain tumors are the leading cause of childhood cancer deaths in developed countries. They also represent the most common solid tumor in this age group, accounting for approximately one-quarter of all pediatric cancers. Developments in neuro-imaging, neurosurgical techniques, adjuvant therapy and supportive care have improved survival rates for certain tumors, allowing a future focus on optimizing cure, whilst minimizing long-term adverse effects. Recent times have witnessed a rapid evolution in the molecular characterization of several of the common pediatric brain tumors, allowing unique clinical and biological patient subgroups to be identified. However, a resulting paradigm shift in both translational therapy and subsequent survival for many of these tumors remains elusive, while recurrence remains a great clinical challenge. This review will provide an insight into the key molecular developments and global co-operative trial results for the most common malignant pediatric brain tumors (medulloblastoma, high-grade gliomas and ependymoma), highlighting potential future directions for management, including novel therapeutic options, and critical challenges that remain unsolved.

Pediatric Myxopapillary Ependymomas: A Clinicopathologic Evaluation

Myxopapillary ependymomas (MPEs) have an indolent clinical course, corresponding to World Health Organization Grade I. A total of 13 pediatric MPEs have been reported in the literature with "anaplastic features," including elevated proliferative activity (≥5 mitoses/10 high-power fields), necrosis, and microvascular proliferation. No consensus exists regarding the prognostic significance of such features. A retrospective clinicopathologic review of pediatric MPEs diagnosed between 1996 and 2018 at Mayo Clinic was performed. Totally, 8 pediatric MPEs (6 male; age: 7.52 to 16.88 y) were identified. Totally, 3 had disseminated disease at presentation. All patients underwent surgical resection (7 gross total; 1 subtotal). Totally, 5 cases harbored ≥5 mitoses/10 high-power fields (range: 5 to 9), 3 of which showed necrosis (2 with disseminated disease). Postsurgery, 2 patients received radiation; one with disseminated disease and another with increased mitotic activity/necrosis; neither has recurred (follow-up: 1.18 and 3.19 y). In all, 2 patients with disseminated disease, elevated mitotic activity, and necrosis had new metastatic disease/progression of nonresected metastatic foci (2.6 and 26.8 mo), received radiation therapy, and remain progression free (3.01 and 9.34 y). All patients are alive (median follow-up 1.31 y, range: 0.66 to 11.75). Among pediatric MPEs, the concurrent presence of elevated mitotic activity and necrosis may be associated with an aggressive clinical course, warranting closer surveillance and consideration of adjuvant therapies.

Outcome After Treatment of Spinal Ependymoma in Children and Adolescents: Long-Term Follow-up of a Single Consecutive Institutional Series of 33 Patients Treated Over Eight Decades

BACKGROUND

Long-term outcomes for pediatric patients treated for spinal ependymoma are unknown.

METHODS

We performed a retrospective analysis of outcome data from 33 children and young adults (0-22 years) who were operated on for a spinal ependymoma at our institution during the last 8 decades (1938-2019).

RESULTS

Nineteen patients are alive, with follow-up period up to 60 years. Twelve of them are tumor-free, and 7 are alive with disease. Fourteen patients are dead, 9 of them due to recurrent and/or progressive disease 1-56 years (median: 11 years) after the initial surgery. Four of the deceased patients were treated before 1948, 3 of them with excellent long-term survival for 62-66 years after the initial surgery. Tumor recurrence was observed in half of the patients, both local at the site of the primary tumor resection as well as widespread intraspinal presentations. Recurrences were observed within months but also occurred after up to 20 years after initial treatment. After the implementation of magnetic resonance imaging in 1987, details of recurrent disease became more easily demonstrated. Repeated resections were performed when the symptomatic spinal disease was in progress (n = 11). Furthermore, 2 patients have intracranial tumor manifestations, 1 of them underwent resection of a suprasellar tumor in 1991. Four deceased patients experienced aggressive extraspinal progressive disease requiring multiple surgeries, including pulmonary metastasis in 1 of them.

CONCLUSIONS

Pediatric spinal ependymomas can be treated with favorable results and functional outcome may be good even after more than half a century of follow-up. Nevertheless, unexpected and late recurrences may occur, and life-long follow-up is therefore recommended.

Outcomes following limited-volume proton therapy for multifocal spinal myxopapillary ependymoma

PURPOSE

Spinal myxopapillary ependymoma (MPE) often presents with a multifocal distribution, complicating attempts at resection. There remains no standard approach to irradiating these patients. We report disease control and toxicity in pediatric patients with multifocal spinal MPE treated with limited-volume proton therapy.

MATERIALS/METHODS

Twelve patients (≤21 years old) with multifocal spinal MPE were treated between 2009 and 2018 with limited-volume brain-sparing proton therapy. Median age was 13.5 years (range, 7-21). Radiotherapy was given as adjuvant therapy after primary surgery in five patients (42%) and for recurrence in seven (58%). No patient received prior radiation. Eleven patients (92%) had evidence of gross disease at radiotherapy. Eleven patients received 54 GyRBE; one received 50.4 GyRBE. Treatment toxicity was graded per the CTCAEv4.0. We estimated disease control and survival using the Kaplan-Meier product-limit method.

RESULTS

The median follow-up was 3.6 years (range, 1.8-10.6). The five-year actuarial rates of local control, progression-free survival, and overall survival were 100%, 92%, and 100%, respectively. One patient experienced an out-of-field recurrence in the spine superior to the irradiated region. No patients developed in-field recurrences. Following surgery and irradiation, one patient developed grade three spinal kyphosis and one patient developed grade 2 unilateral L5 neuropathy.

CONCLUSION

54 GyRBE to a limited volume appears effective for disseminated spinal MPE in both the primary and salvage settings, sparing children the toxicity of full craniospinal irradiation. Compared with historical reports, this approach using proton therapy improves the therapeutic ratio, resulting in minimal side effects and high rates of disease control.

Pediatric ependymoma: an overview of a complex disease

Pediatric ependymomas comprise biologically distinct tumor entities with different (epi)genetics, age distribution and localization, as well as a different prognosis. Regarding risk stratification within these biologically defined entities, histopathological features still seem to be relevant. The mainstay of treatment is gross total resection (GTR) if possible, achieved with intraoperative monitoring and neuronavigation-and if necessary second surgery-followed by adjuvant radiation therapy. However, there is growing evidence that some ependymal tumors may be cured by surgery alone, while others relapse despite adjuvant treatment. To date, the role of chemotherapy is not clear. Current therapy achieves reasonable survival rates for the majority of ependymoma patients. The next challenge is to go beyond initial tumor control and use risk-adapted therapy to reduce secondary effect and therapy-induced morbidity for low-risk patients and to intensify treatment for high-risk patients. With identification of specific alterations, targeted therapy may represent an option for individualized treatment modalities in the future.

Preoperative Intracranial Dissemination of Spinal Myxopapillary Ependymoma Attributed to Tumor Hemorrhage

BACKGROUND

Spinal myxopapillary ependymoma (SME), generally considered a benign entity, can exhibit brain and whole-spine metastases as well as local recurrence after surgery. However, the presence of preoperative retrograde intracranial dissemination at the time of diagnosis is very rare.

CASE DESCRIPTION

We report a case of SME in a 22-year-old man who presented with acute exacerbation of chronic back pain shooting down both thighs and weakness in both legs. Magnetic resonance imaging of the brain and whole spine showed an enhancing mass occupying the majority of the spinal canal at the L1-L2 level and multiple foci dissemination, including in the right pons, lateral midbrain, and occipital lobe, and at the C7, Th6, L4, and S2 levels of the spinal canal at the time of diagnosis. On gross total removal of the dominant tumor located at the L1-L2 level, severe intradural arachnoiditis and syrinx filled with xanthochromic cerebrospinal fluid was noted, indicating the presence of previous tumor hemorrhage. Histopathologic analysis of the tumor supported SME diagnosis, and <1% of cells showed Ki-67 expression. We speculated that distant retrograde dissemination could have been attributed to metastatic spread through cerebrospinal fluid caused by tumor hemorrhage, which may explain distant dissemination despite low expression of Ki-67.

CONCLUSIONS

Screening of the whole brain and spine at the time of diagnosis is imperative when tumor is detected at any level of the neuraxis. The present case of SME with a preoperative intracranial lesion is the fifth case documented in the medical literature.

Invasive myxopapillary ependymoma of the lumbar spine: A case report

BACKGROUND

Myxopapillary ependymomas are rare spinal tumours. Although histologically benign, they have a tendency for local recurrence.

CASE SUMMARY

We describe a patient suffering from extra- and intradural myxopapillary ependymoma with perisacral spreading. He was treated with subtotal resection and postoperative radiation therapy. After treatment, he experienced slight sphincter disorders and lumboischialgic pain with no motor or sensory disturbances. Eight months later, a tumour regression was documented. The patient is still followed-up regularly.

CONCLUSION

Lumbar myxopapillary ependymomas may present with lumbar or radicular pain, similar to more trivial lesions. Magnetic resonance imaging (MRI) is the primary modality for diagnosis. The treatment aim is to minimize both tumour and therapy-related morbidity and to involve different treatment modalities.

Pediatric ependymoma: current treatment and newer therapeutic insights

Advances in genomic, transcriptomic and epigenomic profiling now identifies pediatric ependymoma as a defined biological entity. Molecular interrogation has segregated these tumors into distinct biological subtypes based on anatomical location, age and clinical outcome, which now defines the need to tailor therapy even for histologically similar tumors. These findings now provide reasons for a paradigm shift in therapy, which should profile future clinical trials focused on targeted therapeutic strategies and risk-based treatment. The need to diagnose and differentiate the aggressive variants, which include the posterior fossa group A and the supratentorial RELA fusion subtypes, is imperative to escalate therapy and improve survival.

Differentiation of spinal myxopapillary ependymomas from schwannomas by contrast-enhanced MRI

BACKGROUND

Spinal myxopapillary ependymomas (MPEs) and schwannomas (SCHs) are both frequently located at the conus and caudal regions. The differentiation between MPEs and SCHs before surgery is crucial. Signal patterns of MPEs and SCHs on T2-weighted (T2W) magnetic resonance imaging (MRI) are diverse. Gadolinium (Gd+)-enhanced areas in MRI scans areas are areas where tumor cells are abundant. Therefore, investigating these enhanced areas should facilitate the differentiation. This study aimed to evaluate Gd+ areas in MRI scans in spinal MPEs and SCHs. Furthermore, the relation between MRI pattern and pathological features was investigated.

METHODS

In total, 41 patients with spinal MPEs (n = 7) or SCHs (n = 34) around the conus medullaris were included. SCHs were classified per the Gd+ area of the tumor on T1-weighted (T1W) contrast images, into Gd+ areas with T2W hyperintensity (Gd+/T2high) (n = 4, 11.8%) or Gd+ areas with T2W isointensity (Gd+/T2iso) (n = 30, 88.2%). Four patients with Gd+/T2iso were selected randomly for comparison. In three patient groups, T2 values at the Gd+ area and tumor cell density as measured by HE stains (cell density) were compared.

RESULTS

T2 values at the Gd+ area was higher in patients with MPE than in those with SCH with Gd+/T2high, and significantly higher than that in patients with SCH with Gd+/T2iso. Cell density was significantly lower in patients with MPEs than for those with SCHs with Gd+/T2high, and those with SCHs with Gd+/T2iso.

CONCLUSION

The evaluation of the Gd+ area proved useful because it excludes cysts or necrotic portions. If the Gd+ area is hyperintense on T2WI, MPEs can be suspected. If the Gd+ area is isointense on T2WI, SCHs can be suspected. There were several exceptional cases of SCH with a Gd+ area that was hyperintense on T2WI. This could be explained by pathological findings showing low cell density, as is typical for MPEs.

EANO guidelines for the diagnosis and treatment of ependymal tumors

Ependymal tumors are rare CNS tumors and may occur at any age, but their proportion among primary brain tumors is highest in children and young adults. Thus, the level of evidence of diagnostic and therapeutic interventions is higher in the pediatric compared with the adult patient population.The diagnosis and disease staging is performed by craniospinal MRI. Tumor classification is achieved by histological and molecular diagnostic assessment of tissue specimens according to the World Health Organization (WHO) classification 2016. Surgery is the crucial initial treatment in both children and adults. In pediatric patients with intracranial ependymomas of WHO grades II or III, surgery is followed by local radiotherapy regardless of residual tumor volume. In adults, radiotherapy is employed in patients with anaplastic ependymoma WHO grade III, and in case of incomplete resection of WHO grade II ependymoma. Chemotherapy alone is reserved for young children <12 months and for adults with recurrent disease when further surgery and irradiation are no longer feasible. A gross total resection is the mainstay of treatment in spinal ependymomas, and radiotherapy is reserved for incompletely resected tumors. Nine subgroups of ependymal tumors across different anatomical compartments (supratentorial, posterior fossa, spinal) and patient ages have been identified with distinct genetic and epigenetic alterations, and with distinct outcomes. These findings may lead to more precise diagnostic and prognostic assessments, molecular subgroup-adapted therapies, and eventually new recommendations pending validation in prospective studies.

Metastases of spinal myxopapillary ependymoma: unique characteristics and clinical management

OBJECTIVE

Myxopapillary ependymoma is a benign WHO Grade I tumor most commonly located in the conus–cauda equina region of the spine. Although this tumor is defined by an overall excellent survival, dissemination throughout the whole neuraxis occurs frequently. The current study evaluated the clinical characteristics and significance of myxopapillary ependymoma metastases.

METHODS

Patients who underwent surgery from 2005 to 2015 for treatment of spinal myxopapillary ependymoma were included in the study. Charts were reviewed for primary tumor symptoms and initial treatment, local recurrence, response to salvage therapy, and presence and behavior of distant metastases.

RESULTS

Nineteen patients with spinal myxopapillary ependymoma were included in the study (52.6% female). The median age at first diagnosis was 32 years old (range 9–58 years old), and 26.3% were ≤ 18 years old. The median follow-up of all included patients was 48 months (range 6–456 months). Of the primary tumors, 84.2% were located in the lower thoracic or upper lumbar spine, spanning 1–3 levels in 94.7%. All patients underwent surgery for initial treatment: in 78.9% a gross-total resection (GTR) was achieved, with adjuvant radiation therapy (RT) in 20%. Of the 21.2% who underwent a subtotal resection (STR), 75% underwent postoperative RT. Tumor progression was noted in 26.3% of patients after a median 36-month follow-up (range 12–240 months). In 57.9% of patients, distant metastases were found, of which 36.4% were present at initial diagnosis. Further metastases occurred within a median of 20 months (range 2–360 months). Following a diagnosis of metastatic tumor, 72.7% did not show progression and no symptoms were observed during a median follow-up of 36 months (range 6–216 months). Metastases occurred in all parts of the neuroaxis, but were principally localized in the thoracic and sacral spine in 38.9% and 33.3%, respectively; the brain was involved in 11.1%. In 54.5%, more than 1 level was affected. Overall survival was 100% with an excellent clinical and neurological outcome in 78.9% of cases.

CONCLUSIONS

Metastatic dissemination within the CNS can be observed in many patients with myxopapillary ependymoma. GTR of the primary tumor should be the primary treatment goal, and additional RT is recommended after STR. For distant metastases of myxopapillary ependymoma without clinical manifestation, close clinical and MRI follow-up represents a sufficient strategy because most of the metastases remain asymptomatic and do not show progression over time. Additional resection or irradiation as salvage therapy would be recommended if metastases become symptomatic.

Primary Seeding of Myxopapillary Ependymoma: Different Disease in Adult Population? Case Report and Review of Literature

Myxopapillary ependymoma (MPE) is a slow-growing tumor, occurring most often in adults. It originates from the filum terminale in the area of the conus medullaris and cauda equina and is considered a benign lesion. Despite this classification, however, recurrence after both partial and gross total resection is well known. In the pediatric population, primary MPE seeding and generally more aggressive clinical course is well documented and treated through gross total resection, if possible, followed by irradiation. In adults, however, primary MPE seeding is rarely seen. There are few prior reports describing primary metastases into multiple spinal locations in an adult before resection of an MPE. The reason for this difference among pediatric and adult MPE remains unclear. We present the case of a 32-year-old man with primary seeding of an MPE into multiple lumbosacral areas. The patient underwent gross total resection of the lesions and had an uneventful postoperative course. Primary seeding could be a sign of aggressive behavior in this tumor. Complete craniospinal magnetic resonance imaging studies should be done before and after surgery in patients who present with a multifocal primary MPE. Furthermore, patients with a history of primary tumor seeding of MPE should be thoroughly evaluated radiologically. Unlike in pediatric populations, the need for postoperative irradiation in adults is less clear and further studies-particularly genetic ones-are warranted.

Concomitant Double Tumors of Myxopapillary Ependymoma Presented at Cauda Equina-Filum Terminale in Adult Patient

A 32-year-old man presented with gradually increasing bilateral buttock pain. He had intermittent claudication. Multiple, homogenously enhanced intradural extramedullary lesions at L2-L3 and L5-S1 levels were observed on magnetic resonance imaging. The tumors were debulked and were removed in piecemeal pattern until they had completely been resected. Histopathological examination of the surgical specimens confirmed that both tumors were myxopapillary ependymomas (MPE). MPE presenting as concomitant double tumor at conus-cauda-filum level are very rare. This kind of presentation could not be directly considered as dissemination, since both tumors were in the site of classical origin of MPE. Ten cases of double spinal MPEs have been reported to date. Including the present case, analysis of the 11 patients revealed some facts. There is a male predominance, which is opposite to the ependymomas that are commonly observed in females. Median age at presentation is 15 years. Most pronounced symptom is low back pain that sometimes radiates to lower extremities. Surgical approach was aimed in all tumors, which could be succeeded in all tumors except one. Adjuvant radiation therapy was applied in 5 patients. No recurrences have been reported after surgery or surgery + radiotherapy regimens.