A static perimetric technique believed to test receptive field properties: responses near visual field lesions with sharp borders.
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A general review and update in the management of CNS tumours using medulloblastoma as the main model is given in this article. Special emphasis has been placed on the benefits of combined modality treatment for brain tumours. The pathogenesis and management of these tumours is discussed and recommendations made for treatment in developing countries.
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The purpose of this review is to clarify for the nonneuropathologist some of the confusing issues concerning the classification of brain tumors. Following a short discussion of the commonly used methods to diagnose brain tumors clinically (frozen section, light and electron microscopy, immunohistochemistry), the general principles of classifying neural tumors are presented. Grading of tumors on the basis of histological anaplasia, and the concept that tumor cells can be related to specific cytological stages of normal cellular development (cytogenetic classification) are presented. The World Health Organization system of classifying neural tumors is an attempt to develop a standardized classification scheme with as few interpretative controversies as possible, but it has required revision as new information has been gained. The major clinical and biological features of the commonest tumor groups are then discussed. It is unlikely that improvements in the classification of brain tumors will be based solely on histological information. Definitions of tumor entities that will provide more accurate prognoses and bases for effective therapy will require considerably more information at the molecular level than is currently available.
BACKGROUND: The chances for cure in medulloblastoma, supratentorial primitive neuroectodermal tumors (stPNET) and intracranial germ cell tumors have decisively improved within the last decades. Today long-term survival in the range between 60% and 80% and more than 90%, respectively, can be achieved. The low incidence of brain tumors in childhood and the necessity for optimal patient care has led to the fact that more than 90% of children are treated within national and international controlled studies today in order to assure a constant improvement of therapeutic outcome. Recent developments in neurosurgery achieved complete tumor resections in the majority of children at a low risk for morbidity and mortality. METHODS: Systemic irradiation of neuroaxis is an essential part in the management of medulloblastoma, stPNET and intracranial germ cell tumors. The introduction of quality assurance programs in radiooncology assures a precise radiotherapy of target volumes and is a prerequisite to improve survival. RESULTS: Hyperfractionated radiotherapy has the potential of increasing dose to tumor more safely without increasing the risk for late adverse effects. Pilot studies revealed excellent tumor control in medulloblastoma with acceptable acute toxicity and a long-term survival of up to 96%. In medulloblastoma stereotactic radiation techniques reveal an acceptable toxicity and promising results in tumor control in recurrent disease or as primary treatment. They are now part of future treatment protocols in case of persisting residual tumor. Radiotherapy alone in pure germinoma is continuously yielding high cure rates. In secreting germ cell tumors cisplatin containing chemotherapies in conjunction with radiotherapy achieve a long-term survival rate of 80% today. Especially in high risk medulloblastoma and secreting germ cell tumors chemotherapies are playing an increasingly important role in the interdisciplinary management. It can be expected that future developments of chemotherapeutic protocols and the introduction of new cytostatic substances will further improve the therapeutic outcome. CONCLUSIONS: The therapeutic endeavors of all those caring for children are aiming to study modifications of the therapeutic components in the interdisciplinary approach in order to optimize the therapeutic strategies. In future the affected children and young adolescents should be accrued for the forthcoming cooperative, prospective trial HIT 2000 and ongoing trial SIOP CNS GCT 96, respectively, in order to provide the body of data supporting the selection of novel and optimized approaches for future treatment strategies.
To reduce the sequelae from CNS irradiation (RT), 16 children younger than 3 years with medulloblastoma-PNET (13 cases) and ependymoma (3 cases) were treated between 1987-1993 according to different postsurgical chemotherapy (CT) programs. None of these patients presented with metastases. Eleven patients were rendered disease-free by surgery, while 5 had residual tumor. Adjuvant therapy depended on patients' age, postsurgical status and parents' consent to radiotherapy (RT). Nine of the 16 infants remained alive in continuous complete remission from the first neoplasm (median follow-up 7 years). Three of them had been treated with CT alone and 6 with combined CT + RT (posterior fossa 4, whole CNS 2). Seven patients relapsed a median of 13 months after diagnosis, and all 7 of them died of their disease. Despite the omission of RT in 6 of the 16 patients and administration of only focal RT in 8 of the 16, the outcome of this series was satisfactory. Local failure (in 5/7 patients) was the major problem, despite the high dose of RT used in 2 of these 5. In 4 of 6 evaluable children school performance was satisfactory. One child in whom the entire CNS was irradiated developed glioblastoma multiforme 120 months after the first diagnosis of medulloblastoma.
p67 (Munc-18), is a neuron-specific protein of 67 kDa, known for its ability to bind with syntaxin and also to copurify with neuronal cdc2-like kinase. Earlier, in situ hybridization and immunocytochemical analysis of rat trigeminal ganglion and hippocampal cells demonstrated the specific localization of p67 in nerve cells and its rich distribution in axons. In the present study, we have looked for p67 expression in normal human brain and various neuroectodermal tumors. Immunohistochemical and Western immunoblot analysis of normal human brain tissue using antibodies against the N- and C-termini of p67 demonstrated the specific localization of this protein in postmitotic neurons but not in glia. Among neuroectodermal tumors, expression of p67 was observed in 100% of the tumors of neuronal origin studied, especially in the mature neuronal cell population of these tumors. Western immunoblot analysis of non-neuronal neuroectodermal tumors failed to reveal the expression of this protein in majority of cases. However, in gliomas and meningiomas, mild cytoplasmic immunohistochemical staining of neoplastic cells was noted in 64.7% and 25% of cases, respectively. Observed mild immunohistochemical staining of these tumors could be due to immunoreactivity to low molecular weight degraded products of p67, as seen on Western blot. The findings suggest that p67, by virtue of its ability to be expressed in postmitotic neurons of adult human brain and in tumors of neuronal origin, may serve as a molecular tool to understand the growth and differentiation of the nervous system in general.
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PURPOSE: Analysis of the feasibility and effect of hyperbaric oxygen treatment (HBO) on cognitive functioning in patients with cognitive disorders after irradiation of the brain. PATIENTS AND METHOD: Seven patients with cognitive impairment after brain irradiation, with an interval of at least 1.5 years after treatment, were treated with 30 sessions of HBO in a phase I-II study. A comprehensive neuropsychological test battery was performed before treatment, at 3 and 6 months thereafter. Patients were randomized into an immediate treatment group and a delayed treatment group. The delayed group had a second neuropsychological test at 3 months without treatment in that period and started HBO thereafter. RESULTS: All eligible patients completed the HBO treatment and the extensive neuropsychological testing. One out of seven patients had a meaningful improvement in neuropsychological functioning. At 3 months there was a small, but not significant benefit in neuropsychological performance for the group with HBO compared to the group without HBO treatment. Six out of seven patients eventually showed improvement after HBO in one to nine (median 2.5) of the 31 tests, although without statistical significance. CONCLUSION: HBO treatment was feasible and resulted in a meaningful improvement of cognitive functioning in one out of seven patients. Overall there was a small but not significant improvement.
BACKGROUND: Treatment of childhood low-grade gliomas is a challenging issue owing to their low incidence and the lack of consensus about "optimal" treatment approach. MATERIAL AND METHODS: Reports in the literature spanning 60 years of radiation therapy, including orthovoltage, megavoltage and recently modern high-precision treatments, were reviewed with respect to visual function, survival, prognostic factors, dose prescriptions, target volumes, and treatment techniques. Based on these experiences, future strategies in the management of childhood low-grade glioma are presented. RESULTS: Evaluation of published reports is difficult because of inconsistencies in data presentation, relatively short follow-up in some series and failure to present findings and results in a comparable way. Even with the shortcomings of the reports available in the literature, primarily concerning indications, age at treatment, dose response, timing and use of "optimal" treatment fields, radiation therapy continues to play an important role in the management of these tumors achieving long-term survival rates up to 80% or more. Particularly in gliomas of the visual pathway, high local tumor control and improved or stable visual function is achieved in approximately 90% of cases. Data on dose-response relationships recommend dose prescriptions between 45 and 54 Gy with standard fractionation. There is consensus now to employ radiation therapy in older children in case of progressive disease only, regardless of tumor location and histologic subtype. In younger children, the role of radiotherapy is unclear. Recent advances in treatment techniques, such as 3-D treatment planning and various "high-precision" treatments achieved promising initial outcome, however with limited patient numbers and short follow-ups. CONCLUSIONS: Radiation therapy is an effective treatment modality in children with low-grade glioma regarding tumor control and improvement and/or preservation of neurologic function or vision, respectively. More prospective studies are needed to address the impact of modern radiation therapy technologies (including intensity-modulated radiotherapy) on outcome especially in the very young and to define the role of radiation therapy as a part of a comprehensive treatment approach. The forthcoming prospective trial SIOP/GPOH LGG RT 2003 is addressing this issue.
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The human saccadic system is potentially unstable and may oscillate if the burst neurons, which generate saccades, are not inhibited by omnipause neurons. A previous study showed that combined saccade vergence movements can evoke oscillations in normal subjects. We set out to determine: 1) whether similar oscillations can be recorded during other paradigms associated with inhibition of omnipause neurons; 2) whether lesions of the fastigial nuclei disrupt such oscillations; and 3) whether such oscillations can be reproduced using a model based on the coupling of excitatory and inhibitory burst neurons. We recorded saccadic oscillations during vergence movements, combined saccade-vergence movements, vertical saccades, pure vergence and blinks in three normal subjects, and in a patient with saccadic hypermetria due to a surgical lesion affecting both fastigial nuclei. During combined saccade-vergence, normal subjects and the cerebellar patient developed small-amplitude (0.1 - 0.5 degrees), high-frequency (27-35 Hz), conjugate horizontal saccadic oscillations. Oscillations of a similar amplitude and frequency occurred during blinks, pure vergence and vertical saccades. One normal subject could generate saccadic oscillations voluntarily (approximately 0.7 degrees amplitude, 25 Hz) during sustained convergence. Previous models proposed that high-frequency eye oscillations produced by the saccadic system (saccadic oscillations), occur because of a delay in a negative feedback loop around high-gain, excitatory burst neurons in the brainstem. The feedback included the cerebellar fastigial nuclei. We propose another model that accounts for saccadic oscillations based on 1) coupling of excitatory and inhibitory burst neurons in the brainstem and 2) the hypothesis that burst neurons show post-inhibitory rebound discharge. When omnipause neurons are inhibited (as during saccades, saccade-vergence movements and blinks), this new model simulates oscillations with amplitudes and frequencies comparable to those in normal human subjects. The finding of saccadic oscillations in the cerebellar patient is compatible with the new model but not with the recent models including the fastigial nuclei in the classic negative-feedback loop model. Our model proposes a novel mechanism for generating oscillations in the oculomotor system and perhaps in other motor systems too.
We describe CT and MRI appearances in two children with pathologically proven gliofibromas, in the cerebrum and cerebellum. A striking finding was lack of high signal on T2-weighted MRI.
Infantile myofibromatosis is a disorder of infancy and early childhood characterised by single or multiple nodular lesions localised to bone, muscle, viscera, subcutaneous tissue or central nervous system. These pseudotumours contain smooth muscle and fibroblasts. The prognosis depends on the amount, as well as location, of the lesions. We present the radiological findings on plain films, US and MRI of a newborn who presented at birth with multiple organ involvement, including the CNS. To our knowledge, the comprehensive imaging features of such severe and multifocal involvement have not previously been reported.
The incidence of primary CNS tumours in children and adolescents (0-20 years of age) was investigated for the time period 1970-1989 using the records of the East German National Cancer Registry. 2906 such tumors were registered. 93.2% of them were histopathologically confirmed. The incidence was 31.0/1,000,000 for the male and 25.9 for the female population. 2719 (93.6% of all tumours) were intracranially and only 187 (6.4%) intraspinally situated. The incidence of the CNS tumours increased during the time period of the investigation. This increase was more pronounced in the male and less in the female population. The most common tumour types were gliomas (38.7% of all registered CNS tumours), medulloblastomas (14.0%) and ependymomas (10.9%). 130 primary CNS tumours occurred in infants (less than 1 year of age). Among these tumours were 21 ependymomas and 21 choroid plexus tumours.
INTRODUCTION: We report two cases of radiation-induced intracranial tumours after treatment for medulloblastoma presenting in children with nevoid basal cell carcinoma syndrome. DISCUSSION: These cases illustrate the need for judicious use of post-operative radiotherapy as secondary tumors are commonly reported. This is particularly important as the initial tumour in this cohort is of the 'less aggressive' desmoplastic subtype.
We investigated the age-related location, gender distribution, and histology of 107 brain tumors in children under 4 years of age seen in our department between 1984 and 1997. The male-to-female ratio was 1.4 (62/45 cases) with a prevalence of supratentorial tumors (60/47 = 1.3); the main histological entity was astrocytoma (33.6%), followed by ependymoma (14.0%). In the 1st year of life 22 cerebral neoplasms became clinically apparent. A higher ratio for supratentorial tumors was revealed (17/5 = 3.4), but without gender preference, and primitive neuroectodermal tumors (PNET) were the most frequent (5/22). In the 2nd year 25 tumors were found. The male-to-female ratio was 1.5 (15/10) and the supratentorial-to-infratentorial ratio, 1.1 (13/12). The two most common entities were astrocytoma and ependymoma (6 cases each). In addition, a survey of previously published investigations into this subject was performed and a compilation of data on 1960, 545 and 1084 tumors in children below the age of 1, 2 and 4 years, respectively, was prepared, which makes it the most extensive review of brain tumors of infancy and early childhood yet undertaken.