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Introduccion: el ependimoma mixopapilar (EM) es un tumor glial ependimario que afecta predominantemente a los adultos jovenes, se origina en el filum terminale, la cauda equina y el cono medular. Caso clinico: se presenta el caso de una paciente en quien durante el estudio de un dolor radicular se logra detectar ependimoma mixopapilar gigante, el cual comprometia gran parte del hueso sacro, mostrando un comportamiento localmente agresivo con intensa osteolisis. Conclusion: se discutieron las posibles teorias que explican la presencia de estos tumores a nivel sacro, en especial la presencia de remanentes embrionarios de tejido ependimario en los niveles mas caudales del canal vertebral y los posibles mecanismos que explican el comportamiento agresivo de estos tumores histologicamente benignos. Rev.cienc.biomed. 2015;6(2):348-353 PALABRAS CLAVE Columna vertebral; Ependimoma mixopapilar; Neoplasia extradural; Sacro; Region sacrococcigea. SUMMARY Introduction: myxopapillary ependymoma (MP) is a glial ependymal tumor that mainly affects young adults. The tumor originates in the filum terminale, the cauda equina and the conus medullaris. Case record: the case presented in a patient in whom a giant myxopapillary ependymoma was detected during a medical checkup for root pain. The tumor involved the sacral bones showing a locally aggressive behavior with intense osteolysis. Conclusion: possible theories that explain the presence of these tumors in sacral bones were discussed, focusing in the presence of embryonic remnants of ependymal tissue in the most caudal levels of the spinal canal, and the possible mechanisms that explain the aggressive behavior of these histologically benign tumors. Rev.cienc.biomed.2015; 6(2):348-353 KEYWORDS Spine; Myxopapillary ependymoma; Epidural neoplasm; Sacrum;Sacrococcygeal region.

We report a case of spinal ependymoma with ZFTA‐YAP1 fusion, occurring in a 5‐year‐old boy who complained of back pain. It was high‐grade ependymoma, developed in the spinal cord at the level of T9‐12. Since ZFTA‐YAP1 fusion‐positive ependymoma has never been reported in the spinal cord, this case is exceptional and worth reporting because the anatomical location, genetics, and epigenetics are important parameters in the classification of the ependymal tumor. This is the first case of spinal ependymoma harboring ZFTA‐fusion to be diagnosed by NGS and Sanger studies to the best of our knowledge.

Sacrococcygeal myxopapillary ependymoma (MPE) is an uncommon type I glial tumor detected most frequently in the lumbosacral area of adolescents and children. It is usually presented as an intradural ependymal tumor that originates from the filum terminale and other locations within the ventricular system along the craniospinal axis. In rare cases, however, MPE may develop as a primary subcutaneous tumor in the sacrococcygeal area. Tumors can also appear as a dorsal sacrococcygeal growth or subcutaneous nodule. In this case report, we describe a rare case presenting as a subcutaneous sacrococcygeal mass in an elderly female that was subsequently resected and confirmed as subcutaneous MPE. The current standard treatment for MPE is maximal surgical resection with or without postoperative radiotherapy based on the locoregional extent and histological grading. However, there is limited evidence that radiotherapy for oligometastatic foci improves longevity or extends the time to recurrence. In addition to this case report, we provide a comprehensive review of similar cases and case series in the medical literature. Prospective studies evaluating the efficacy of resection and/or radiotherapy are required for improved management of extradural MPE.

Treatment of spinal ependymoma is still challenging because of a concern of postoperative neurological deficit, which derived from its intramedullary location. Despite recent progression of adjuvant therapy, surgical resection is still a mainstay of the treatment, which can lead to an actual cure. To achieve successful surgical outcome minimizing the neurological deficits, the development and keeping the dissection plane throughout the tumor removal is the most important. Therefore, it is imperative to understand the anatomical relationship between the tumor and the surrounding tissues based on tumor origin. In this chapter, the authors suggest the concept of the intra-ependymal tumor, instead of the traditional intramedullary tumor for ependymoma based on the tumor origin and anatomical features. This concept may facilitate the development of the dissection plane and leads to the safe and effective removal of spinal ependymoma.

Tuberous sclerosis (TS) is an autosomal dominant inherited disorder that affects multiple organ systems. Usually, children with TS present either with neurocutaneous stigmata or seizures during the early years of life. The mortality and morbidity are related to refractory epilepsy, giant cell astrocytoma and related complications, and multiple angiomyolipomas. The authors have reported an eleven-year-old child in whom focal status and sub-ependymal tumor were the features of the first presentation of tuberous sclerosis. The report further highlights the importance of early identification of cutaneous features by primary care providers and parents to enable early comprehensive multi-disciplinary management.

OBJECTIVEGross-total resection (GTR) is the treatment of choice in the majority of patients suffering from spinal ependymal tumors. In such tumors, the extent of resection (EOR) is considered the key factor for tumor recurrence and thus patient prognosis. However, incomplete resection is not uncommon and leads to increased risk of tumor recurrence. One important cause of incomplete resection is insufficient intraoperative visualization of tumor tissue as well as residual tumor tissue. Therefore, the authors investigated the value of 5-aminolevulinic acid (5-ALA)–induced fluorescence in a series of spinal ependymal tumors for improved tumor visualization.METHODSAdult patients who underwent preoperative 5-ALA administration and surgery for a spinal ependymal tumor were included in this study. For each tumor, a conventional white-light microsurgical resection was performed. Additionally, the fluorescence status (strong, vague, or no fluorescence) and fluorescence homogeneity (homogenous or inhomogeneous) of the spinal ependymal tumors were evaluated during surgery using a modified neurosurgical microscope. In intramedullary tumor cases with assumed GTR, the resection cavity was investigated for potential residual fluorescing foci under white-light microscopy. In cases with residual fluorescing foci, these areas were safely resected and the corresponding samples were histopathologically screened for the presence of tumor tissue.RESULTSIn total, 31 spinal ependymal tumors, including 27 intramedullary tumors and 4 intradural extramedullary tumors, were included in this study. Visible fluorescence was observed in the majority of spinal ependymal tumors (n = 25, 81%). Of those, strong fluorescence was noted in 23 of these cases (92%), whereas vague fluorescence was present in 2 cases (8%). In contrast, no fluorescence was observed in the remaining 6 tumors (19%). Most ependymal tumors demonstrated an inhomogeneous fluorescence effect (17 of 25 cases, 68%). After assumed GTR in intramedullary tumors (n = 15), unexpected residual fluorescing foci within the resection cavity could be detected in 5 tumors (33%). These residual fluorescing foci histopathologically corresponded to residual tumor tissue in all cases.CONCLUSIONSThis study indicates that 5-ALA fluorescence makes it possible to visualize the majority of spinal ependymal tumors during surgery. Unexpected residual tumor tissue could be detected with the assistance of 5-ALA fluorescence in approximately one-third of analyzed intramedullary tumors. Thus, 5-ALA fluorescence might be useful to increase the EOR, particularly in intramedullary ependymal tumors, in order to reduce the risk of tumor recurrence.

Background Intraoperative image guidance using near-infrared indocyanine green videoangiography (ICG-VA) has been used to provide real-time angiographic images during vascular or brain tumor surgery, and it is also being used for spine surgery. Objective To further investigate the benefits and limitations of ICG-VA image-guided surgery for spinal intramedullary tumors through retrospective study. Methods ICG-VA was used in 48 cases that were treated surgically over the past 5 yr. The pathological diagnoses of the tumors included astrocytic tumor, ependymal tumor, cavernous malformation, and hemangioblastoma. Results Localization of normal spinal arteries and veins on the dorsal surface of the spinal cord helped the surgeons determine the length or point of myelotomy. Well-demarcated tumor stain was recognized in limited cases of anaplastic or highly vascularized tumors, whereas the location of cavernous malformation was recognized as an avascular area on the dorsal surface of the spinal cord. Feeding arteries and tumor stain were well differentiated from draining veins in dorsal hemangioblastomas, but not in intramedullary deep-seated or ventral tumors. The preservation of small perforating branches of the anterior spinal artery after successful resection of the tumor could be well visualized. Conclusion ICG-VA can provide real-time information about vascular flow dynamics during the surgery of spinal intramedullary tumors, and it may help surgeons localize the normal circulation of the spinal cord, as well as the feeding arteries and draining veins, especially in highly vascular tumors. However, the benefits of intraoperative ICG-VA might be limited for intramedullary deep-seated or ventral tumors.

Background Ependymal tumors are pathologically defined intrinsic neoplasms originating in the intracranial compartments or the spinal cord that affect both children and adults. The recently integrated classification of ependymomas based on both histological and molecular characteristics is capable of subgrouping patients with various prognoses. However, the application of histological and molecular markers in Chinese patients with ependymomas has rarely been reported. We aimed to demonstrate the significance of histological characteristics, the v-relavian reticuloendotheliosis viral oncogene homolog A (RELA) fusions and other molecular features in ependymal tumors. Methods We reviewed the histological characteristics of ependymal tumors using conventional pathological slides and investigate the RELA fusions and Cylclin D1 (CCND1) amplification by Fluorescence in situ hybridization (FISH) and trimethylation of histone 3 lysine 27 (H3K27me3) expression by immunohistochemistry (IHC) methods. SPSS software was used to analyze the data. Results We demonstrated that hypercellularity, atypia, microvascular proliferation, necrosis, mitosis, and an elevated Ki-67 index, were tightly associated with an advanced tumor grade. Tumor location, necrosis, mitosis and the Ki-67 index were related to the survival of the ependymomas, but Ki67 was the only independent prognostic factor. Additionally, RELA fusions, mostly presented in pediatric grade III intracranial ependymomas, indicated decreased survival times of patients, and closely related to the patients’ age, tumor grade, cellularity, cellular atypia, necrosis and Ki67 index in the intracranial ependymal tumors, whereas reduction of H3K27me3 predicted the worse prognosis in ependymal tumors. Conclusions Histological and molecular features facilitate tumor grading and prognostic predictions for ependymal tumors in Chinese patients.

Background Selection of the access myelotomy is a key issue in surgery for spinal intramedullary tumors. This study focused on surgical outcomes with the posterolateral sulcus (PLS) approach, equivalent to dorsal root entry zone myelotomy. Methods This retrospective study of the 10-year period from 2007 to 2016 included 90 cases of spinal intramedullary lesions (99 operations). A PLS approach was indicated for intramedullary lesions situated laterally in the spinal cord showing no contact with the spinal cord surface. Neurological conditions before and after surgery were carefully assessed objectively. Results A PLS approach was applied in 34 of the 99 operations (34.3%). Among 70 cases involving astrocytic tumor, ependymal tumor, cavernous malformation or hemangioblastoma, 23 cases (32.9%) were operated on using a PLS approach. Microscopically gross total or subtotal removal of the tumor was achieved in 18 of 23 cases (78.3%). These 18 cases demonstrated mild deterioration of motor function on the approach side early after surgery, but usually resolving within several months postoperatively. Average grade of the modified McCormick functional schema before surgery was maintained 6 months postoperatively. Average grade of the sensory pain scale before surgery was significantly improved by 6 months postoperatively. Segmental dysesthesia on the approach side unexpectedly remained in 2 of 18 cases (11.1%) even late after surgery. Conclusions These findings suggest that the PLS approach can provide direct access to tumors with minimal tissue damage, when applied appropriately after careful case selection.

Objective The aim of this work was to evaluate a pediatric ependymoma protein expression that may be useful as a molecular biomarker candidate for prognosis, correlated with clinical features such as age, gender, histopathological grade, ependymal tumor recurrence and patient survival. Patients and methods Immunohistochemistry assays were performed for GNAO1, ASAH1, IMMT, IPO7, Cyclin D1, P53 and Ki-67 proteins. Kaplan-Meier and Cox analysis were performed for age, gender, histopathological grade, relapse and survival correlation. Results We found that three proteins correlate with histopathological grade and relapse; two proteins correlate with survival; one protein does not correlate with any clinical feature. Conclusion Our results suggest that, out of the proteins analyzed, five may be considered suitable prognostic biomarkers and one may be considered a predictive biomarker for response to treatment of pediatric ependymoma.

Study design Spinal ependymoma is a benign central nervous system tumor described as an intramedullary lesion more frequently located at the conus medullaris. It has been described exceptionally in the literature as an intradural extramedullary tumor. Objective Presentation of an extremelly rare location and evolution of extremedullary ependymoma and discussion of its probable origin, differential diagnosis, treatment options, and follow-up. Summary of background data This case demonstrates an unusual location of a benign ependymal tumor in the extramedullary space with a total resection, which recurred in a lower level with a malignant transformation with the same extramedullary location. Methods The authors present the case of a 47-year-old woman with a subacute spinal cord dysfunction and an intradural extramedullary D2-D3 tumor mimicking meningioma or neurinoma. At surgery, an encapsulated intradural extramedullary mass was found, but neither dural attachment nor medullary infiltration was present. Results After complete resection, anatomic-pathologic studies confirmed that the lesion was a benign classic ependymoma. Good neurologic outcome was achieved, and no residual tumor was present at magnetic resonance imaging (MRI) control performed at 3 and 9 months later. One year after surgery, a new intradural extramedullary tumor was found at the D4 level without recurrence at D2. The patient was operated on again, but at this time the histologic study showed an anaplastic ependymoma with a proliferation index of 25% measured by Ki-67. Whole central nervous system radiotherapy was performed. Conclusion All of the previously reported cases of spinal intradural extramedullary ependymomas carried out a benign course. The case we are reporting is the first one in which malignant transformation occurred. This tumor should be taken into account in the differential diagnosis of intradural extramedullary lesions. Moreover, close follow-up is recommended for this unusual location of ependymomas.

BACKGROUND: Sichuan locates at the west part of China and has a total population of 100 million. This is the first statistical report of central nerve system tumors, which were operated and histologically diagnosed, in a large Chinese population. METHODS: All patients data were obtained from 86 medical facilities, which covered all population of Sichuan province. Patients should be operated between 2008 and 2013, and the histology samples were re-reviewed and diagnosis confirmed in the major pathology centers. All central nerve system tumors, including brain tumors and spinal tumors, were collected. All tumors, including primary and metastatic brain tumors, were categorized according to the ICD-10 classification and were reviewed manually. The tumor distribution was analyzed and satisfied by the gender, age, race and tumor sites. The tumor in some minorities, such as Tibetan, was also analyzed. Some molecular markers which were measured in some neuroepithelial tumors were analyzed. RESULTS: The final analytic data set included about 38,000 records. Meningioma (25.7%) ranks the first place in all tumors, then followed in turn by pituitary adenoma (14.7%), glioblastoma (11.8%), metastatic brain tumor, diffuse astrocytoma, ependymal tumor, nerve theath tumor, craniopharyngioma, anaplastic astrocytoma, pilocytic astrocytoma, lymphoma, oligoastrocytoma, oligodendroglioma, ganglioglioma, germ cell tumor, anaplastice oligodendroglioma or oligoastrocytoma, choroid plexus and pineal regional tumor. Gliomas have a higher incidence in the frontal lobe, while metastatic tumors like parietal and occipital lobes. Most tumors in the thalamus or basal ganglia were highly malignant. And ependymal tumors in the spine is more than those in the ventricles. All detailed analysis will be provided in the later article. CONCLUSION: This is a preliminary report of statistical analysis of brain and spinal tumors in a large Chinese population. This report aims to serve as a useful resource for brain tumor clinicians, researchers, as well as patients families.

Spinal cord subependymomas are very rare. Most studies on spinal cord subependymomas have been case reports with literature reviews. This study presented a surgical series of 13 patients with histologically proven spinal cord subependymomas. Their clinical data, radiological findings, operative records, and follow-up outcomes were reviewed. There were 5 male and 8 female patients with a mean age of 39.5 years. The mean follow-up period was 67.8 months. Four tumors were located in the cervical spine, 5 in the cervicothoracic spine, and 4 in the thoracic spine. Gross total resection (GTR) of the tumor with a well-demarcated dissection plane was achieved in 9 cases, and subtotal resection was achieved in 4 cases. The symptoms present before the surgery were improved in 11 cases at last follow-up and the current status of 2 patients had no change compared to the preoperative presentation at last follow-up. The postoperative follow-up magnetic resonance imaging showed no recurrence in the 9 GTR cases during the mean follow-up period of 70.3 months. No recurrence/regrowth of the residual tumors was observed in the 4 STR cases during the mean follow-up period of 62.0 months. Spinal cord subependymomas are amenable to surgical resection. It is possible to achieve GTR of intramedullary subependymomas that have a well-demarcated dissection plane. When GTR cannot be achieved, STR of the lesion for decompression is advised, and follow-up imaging is needed. A good clinical outcome after GTR or STR can be expected.

Ependymomas are one of the most common pediatric malignant brain tumors. Prognosis, especially in young children, remains poor due to their inherent chemo- and radio-resistance and effective treatment remains one of the more difficult tasks in pediatric oncology: up to half of the patients may die from the disease. The only reproducible prognostic factor is the extent of surgery; neither histological grading nor other biomarkers can be used to reliably make treatment decisions in clinical practice. None of the studies identifying new biomarkers have been conducted prospectively, only few have been undertaken within the context of a clinical trial and most have been conducted with limited samples (often including adults and childhood samples). International collaboration is needed to improve ependymoma prognostication.

Purpose: Ependymomas are glial tumors of presumably radial glial origin that share morphologic similarities with ependymal cells. The molecular genetics of ependymomas of supratentorial, infratentorial, and spinal location is heterogeneous. We aimed at identifying pathways operative in the development of infratentorial ependymomas. Experimental Design: To do so, gene expression profiles of tumor cells laser microdissected from infratentorial ependymomas (n = 15) were compared with that of nonneoplastic ependymal cells laser microdissected from autopsy tissue (n = 7). Results: Among 31 genes significantly overexpressed (>5-fold) in ependymomas, transcription factor EVI1 (ecotropic viral integration site 1) showed the highest overexpression (35-fold). Evi-1 protein expression could be confirmed in formalin-fixed, paraffin-embedded samples of 26 of 28 infratentorial ependymomas but only in 7 of 47 nonependymal glial tumors (P < 0.001). Furthermore, MDS1/EVI1 fusion transcripts were detectable in 17 of 28 infratentorial ependymomas and significantly correlated with MGMT (O6-methylguanine-DNA-methyltransferase) promoter hypermethylation (P < 0.05). In primary infratentorial ependymoma cells, transfection with EVI1-specific siRNAs resulted in significant growth inhibition [48 hours: 87% ± 2% and 74% ± 10% as compared with control (mean ± SD; P < 0.001)]. The prognostic role of EVI1 could further be validated in an independent cohort of 39 infratentorial and 26 supratentorial ependymomas on the basis of mRNA expression profiling. Although in supratentorial ependymomas EVI1 expression status had no prognostic impact, in infratentorial ependymomas, high EVI1 expression was associated with shorter overall survival and progression-free survival. Conclusions: To conclude, the transcription factor Evi-1 is overexpressed in infratentorial ependymomas, promotes proliferation of ependymal tumor cells, and is prognostically unfavorable. Clin Cancer Res; 17(11); 3631–7. ©2011 AACR.

Background The 2016 Revised Fourth Edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System recognizes the following ependymal tumor categories: subependymoma (WHO grade I), myxopapillary ependymoma (WHO grade I), ependymoma (WHO grade II) including a number of variants, and anaplastic ependymoma (WHO grade III). In addition, ependymoma, RELA fusion positive, is a newly codified entity that includes the majority of pediatric supratentorial ependymomas. Tumors of choroid plexus include choroid plexus papilloma (WHO grade I), atypical choroid plexus papilloma (WHO grade II), and choroid plexus carcinoma (WHO grade III). Design The aim of this chapter is to summarize current knowledge pertaining to ependymal and choroid plexus lesions. Outcome Clinical, epidemiologic, radiologic, and pathologic features of the various recognized ependymal and choroid plexus neoplasms are presented in detail, special attention given to histologic grading and identification of specific tumor variants. Useful ancillary diagnostic studies (immunohistochemistry, ultrastructural and molecular analyses) are also covered, as are differential diagnostic, prognostic, and treatment considerations. Xanthogranuloma of the choroid plexus is also discussed. Conclusion This chapter comprehensively covers the various categories of ependymal and choroid plexus neoplasms and presents a thoughtful approach to differentiating these tumors from possible diagnostic mimics in both adult and pediatric patients.

The term “low-grade glioma” refers to a heterogeneous group of slowly growing glial tumors corresponding histologically to World Health Organization (WHO) grade I or II. This group includes astrocytic, oligodendroglial, oligoastrocytic and ependymal tumor entities, most of which preferentially manifest in children and young adults. Depending on histological type and WHO grade, growth patterns of low-grade gliomas are quite variable, with some tumors diffusely infiltrating the surrounding central nervous system tissue and others showing well demarcated growth. Furthermore, some entities tend to recur and show spontaneous malignant progression while others remain stable for many years. This review provides a condensed overview concerning the molecular genetics of different glioma entities subsumed under the umbrella of low-grade glioma. For a better understanding the cardinal epidemiological, histological and immunohistochemical features of each entity are shortly outlined. Multiple cytogenetic, chromosomal and genetic alterations have been identified in lowgrade gliomas to date, with distinct genetic patterns being associated with the individual tumor subtypes. Some of these molecular alterations may serve as a diagnostic adjunct for tumor classification in cases with ambiguous histological features. However, to date only few molecular changes have been associated with clinical outcome, such as the combined losses of chromosome arms 1p and 19q as a favorable prognostic marker in patients with oligodendroglial tumors.

Primary extradural ependymomas are rare neoplasms usually of the myxopapillary type. Reports on malignant primary extradural ependymal tumors are exceptionally rare. We here report on a 3-year-old boy with Schinzel-Giedion syndrome (SGS), who presented with lumbar spina bifida occulta and a progressive extraspinal lesion in the subcutaneous sacrococcygeal region. Microscopic examinations revealed an uncommon ependymal tumor with well-differentiated regions reflecting myxopapillary ependymoma and highly anaplastic regions with numerous mitoses, necroses, ependymal rosettes and ependymoblastic rosettes. Final neuropathologic diagnosis was an extraspinal anaplastic ependymal tumor with myxopapillary and ependymoblastic differentiation, corresponding to WHO grade IV. SGS is a very rare disorder with a likely autosomal recessive pattern of inheritance. So far, 42 cases have been reported, among them 7 were diagnosed to have malignant neoplasms, including three malignant sacrococcygeal teratomas, two sacrococcygeal primitive neuroectodermal tumors (PNET), one hepatoblastoma and one malignant kidney tumor. The present case is the first report on an ependymal tumor with a mixture of myxopapillary, anaplastic and ependymoblastic features and the first report on an ependymal tumor arising on the genetic background of SGS.

Ependymomas arise from the ependymal cells at different locations throughout the brain and spinal cord. These tumors have a broad age distribution with a range from less than 1 year to more than 80 years. In some intramedullary spinal ependymomas, mutations in the neurofibromatosis 2 (NF2) gene and loss of heterozygosity (LOH) on chromosome arm 22q have been described. Cytogenetic studies have also identified alterations involving chromosome arm 11q, including rearrangements at 11q13, in ependymomas. We analyzed 21 intramedullary spinal, 14 ventricular, 11 filum terminale and 6 intracerebral ependymomas for mutations in the MEN1 gene, which is located at 11q13, and mutations in the NF2 gene, which is located at 22q12, as well as for LOH on 11q and 22q. NF2 mutations were found in 6 tumors, all of which were intramedullary spinal and all of which displayed LOH 22q. Allelic loss on 22q was found in 20 cases and was significantly more frequent in intramedullary spinal ependymomas than in tumors in other locations. LOH 11q was found in 7 patients and exhibited a highly significant inverse association with LOH 22q (p

We described a 5-month-old girl with Aicardi syndrome accompanied by auditory disturbance and multiple brain tumors. She was admitted to our hospital because she suffered from intractable flexor spasms. Physical examination revealed craniofacial asymmetry, left auricular deformity, scoliosis, and remarkable hypotonia with psychomotor retardation. Abnormal ophthalmological findings included chorioretinopathy with pale and round-shaped peripapillary lacunae, and there was modified hypsarrhythmia in her EEG. MRI revealed multiple brain tumors in the 3rd and the lateral ventricles which are considered to be choroid plexus papilloma with agenesis of the corpus callosum. ACTH therapy was administered because of the intractable seizures. After ACTH therapy, the thresholds of waves I and V were much improved. The interpeak latency of waves I-V of the left ear and the peak latency of wave I of the right ear had been lengthened. Acoustic reflex with contralateral stimulation showed no response in the left ear. These findings indicate that the auditory system is also involved in the Aicardi syndrome and that ACTH is effective for its dysfunction.

Background To assess the role of Fractionated Stereotactic Radiotherapy (FSRT) in the management of ependymomas. Methods From January 1992 to July 2003, FSRT was performed in 19 patients with histologically confirmed ependymomas. The median age was 15 years, 5 patients were younger than 4 years of age. Twelve patients received FSRT as primary postoperative radiotherapy after surgical resection. In 6 patients irradiation of the posterior fossa was performed with a local boost to the tumor bed, and in 4 patients the tumor bed only was irradiated. In 7 patients FSRT was performed as re-irradiation for tumor progression. This patient group was analyzed separately. A median dose of 54 Gy was prescribed in a median fractionation of 5 × 1.8 Gy per week for primary RT using 6 MeV photons with a linear accelerator. For FSRT as re-irradiation, a median dose of 36 Gy was applied. All recurrent tumors were localized within the former RT-field. Results The 5- and 10-year overall survival rates were 77% and 64%, respectively. Patients treated with FSRT for primary irradiation showed an overall survival of 100% and 78% at 3 and 5 years after irradiation of the posterior fossa with a boost to the tumor bed, and a survival rate of 100% at 5 years with RT of the tumor bed only. After re-irradiation with FSRT, survival rates of 83% and 50% at 3-and 5 years, respectively, were obtained. Progression-free survival rates after primary RT as compared to re-irradiation were 64% and 60% at 5 years, respectively. FSRT was well tolerated by all patients and could be completed without interruptions due to side effects. No severe treatment related toxicity > CTC grade 2 for patients treated with FSRT could be observed. Conclusion The present analysis shows that FSRT is well tolerated and highly effective in the management of ependymal tumors. The rate of recurrences, especially at the field border, is not increased as compared to conventional radiotherapy consisting of craniospinal irradiation and a local boost to the posterior fossa.

The characteristics of clear cells of an ependy-moma of the foramen of Monro have been studied by electron microscopy to precisely define its or-ganellar composition and to establish the tumor histogenesis. Our data confirm that the once-thought oligodendroglial is, in fact, an ependymal tumor. Both the scarce number of organelles, owing to the low degree of differentiation, and the abun-dance of hyaloplasmic lipid vacuoles can account for the clear appearance of these tumor cells.

Heterotransplant characteristics of a non-astroglial neuroectodermal tumor cell line EPD-1, established from a cerebellar ependymoma, are described. The tumorigenicity of EPD-1 was established in athymic nude mice by xenografting to brain, eye and subcutaneous tissues. The heterotransplants grew as discrete masses of poorly differentiated tumors with foci of Homer-Wright rosettes and positive reaction with antisera to neuronal-specific enolase (NSE). In the eye, focal ependymal differentiation was apparent with identifica-tion of ependymal rosettes in a densely cellular tumor. Like in vitro studies, the in vivo chromosome studies revealed a homogeneously staining region (HSR) on chromosome 1. The establishment of an animal model of an ependymal tumor will aid in further investigation of its neurobiology and chemotherapeutic responsive-ness.

A fine structural study of a myxopapillary ependymoma of the filum terminale confirms and emphasizes the distinctive morphological features of this tumor. Electron basement membrane production were identified. It is suggested that they are related to the growth of ependymal tumor cells in juxtaposition to the collagen normally present in the conus medullaris and filum terminale.