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This article presents an abstract of the research paper "Pleomorphic Xanthoastrocytoma Combined With Arteriovenous Malformation: A Case Report," which was discussed in the 13th Conference of the Polish Association of Neuropathologist. Pleomorphic xanthoastrocytoma is a rare brain tumor with highly distinct histological and clinical features that occurs usually as a superficial discrete mass lesion in the cerebral hemispheres of young subjects. This usually benign tumor was characterized by extreme cellular and nuclear polymorphism and tumor cell lipidization. Its connection with other maldevelopmental abnormalities is unique.

This article presents an abstract of the research paper "Delayed Neuronal and Glial Changes in SLA Model In Vitro," which was discussed in the 13th Conference of the Polish Association of Neuropathologist. Chronic excitoxicity mediated through the defective glial and neuronal glutamate transport may contribute to several neurodegenerative diseases including amyotrophic lateral sclerosis. To determine the detailed ultrastructural characteristics of excitotoxic motor neuron neurodegeneration, the study used a model of slow excitotoxicity in vitro based on selective inhibition of glutamate uptake.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that involves the upper and lower motor neurons and leads to the patient's death within 5 years after diagnosis. Approximately 2 per 100,000 people worldwide are affected every year. The only FDA-approved drug available for medical treatment is riluzole. It slows the disease progression and improves limb function and muscle strength for 3-4 months. Thus, looking for new therapeutic agents is a pressing challenge. Valproic acid (VPA) is a short-chain fatty acid, widely used for the treatment of seizures and bipolar mood disorder. The beneficial effect of VPA has been documented in different neurodegenerative experimental models, including amyotrophic lateral sclerosis (ALS). The real mechanisms underlying numerous beneficial effects of VPA are complex, but recently it has been postulated that the neuroprotective properties might be related to direct inhibition of histone deacetylase (HDAC). The aim of this ultrastructural study was to evaluate the beneficial effect of VPA on the spinal cord motor neurons (MNs) in a glutamate (GLU)-induced excitotoxic ALS model in vitro. It had been previously documented that chronic GLU excitotoxicity resulted in various MN injuries, including necrotic, apoptotic and autophagic modes of cell death. The present results demonstrated the neuroprotective properties of VPA associated with inhibition of apoptotic and autophagic changes of spinal MNs in a model of neurodegeneration in vitro.

Pleomorphic xanthoastrocytoma (PXA) is a rare, low-grade astrocytic tumour corresponding to WHO grade II that is usually diagnosed in adolescents and young adults with epileptic seizures. Pleomorphic xanthoastrocytoma typically appears as a superficial, often cystic mass lesion predominantly affecting the temporal lobe. Cases with typical pathology and total tumour excision have a favourable prognosis. Occasionally, the tumour reveals anaplastic features and behaves more aggressively due to local recurrences or subarachnoid spread. The treatment of PXA includes gross total resection followed by neuroradiological monitoring. The association between vascular malformations and cerebral gliomas is rarely encountered, especially if both such lesions occur as separate parts of the same tumour. The vascular pathology of such changes most often refers to arteriovenous malformation (AVM), less frequently - cavernous angioma. The coexistence of PXA and AVM is extremely rare, especially when dealing with two distinct patterns found within the same tumour mass. We present a 36-year-old woman with tumour of parasagittal localization in the right occipital lobe that was composed of two different and clearly demarcated components: PXA and vascular lesion of AVM morphology. The pathogenesis of such coexistence remains still unclear.

Erythropoietin (EPO) is a chemokine hormone that is widely distributed throughout the body including nervous system. For last years its role as cytokine involved in many physiological processes out of the bone marrow has been suggested. Moreover, it plays a very important role in CNS as potential neuroprotective agent. There is much evidence that EPO protects neuronal cells in vitro and in vivo models of brain injury, independently of its erythropoietic action. The aim of this study was to determine the potential neuroprotective effects of erythropoietin on the glutamate-mediated injury of motor neurons (MNs) in vitro. The study was performed on organotypic cultures of the rat lumbar spinal cord subjected to glutamate uptake blocker, DL-threo-beta-hydroxyaspartate (THA) and pretreated with EPO. Ultrastructural study evidenced that the spinal cord cultures pretreated with EPO exhibited less severe neuronal injury. The cultures exposed to EPO + THA showed inhibition of early MNs degeneration, including various mode of degenerative changes caused by THA, whereas in the later period the typical postsynaptic necrotic changes of neuronal cells occurred. However, the ultrastructural characteristics of apoptotic MNs changes were not observed during the whole period of observation. The results of this study indicate that, in the model of chronic glutamate excitotoxicity, EPO exhibits the neuroprotective ability mainly through prevention of apoptotic neuronal changes.

Cytidine-5-diphosphocholine (CDP-choline, citicoline) is an endogenous nucleoside involved in generation of phospholipids, membrane formation and its repair. It demonstrates beneficial effects in certain central nervous system injury models, including cerebral ischaemia, neurodegenerative disorders and spinal cord injury. Defective neuronal and/or glial glutamate transport is claimed to contribute to progressive loss of motor neurons (MNs) in amyotrophic lateral sclerosis (ALS). Our previous ultrastructural studies, performed on an organotypic tissue culture model of chronic glutamate excitotoxicity, documented a subset of various modes of MN death including necrotic, apoptotic and autophagocytic cell injury. The aim of this ultrastructural study was to determine the potential neuroprotective effect of CDP-choline on neuronal changes in a glutamate excitotoxic ALS model in vitro. Organotypic cultures of the rat lumbar spinal cord subjected to 100 microM DL-threo-beta-hydroxyaspartate (THA) were pretreated with 100 microM of CDP-choline. The exposure of spinal cord cultures to CDP-choline and THA distinctly reduced the development of typical apoptotic changes, whereas both necrotic and autophagocytic THA-induced MN injury occurred. These results indicate that CDP-choline treatment might exert a neuroprotective effect against neuronal apoptotic changes in a model of chronic excitotoxicity in vitro.

Both the neurotoxic and neuroprotective effects of zinc have been well established, but the exact mechanism of its dual abilities still remains unclear. It has been shown that zinc deficiency leads to progressive neuronal injury. Therefore a safe zinc concentration levels seem to be necessary in neuronal protection from different noxious factors. This study was undertaken to determine the effect of zinc chelating agent--TPEN on neuronal morphological changes in organotypic hippocampal culture and its effect on post-anoxic changes in this model. The study evidenced that exposition to 15 microM of TPEN induced various stages of apoptotic changes in hippocampal pyramidal neurons and enhanced the anoxia-induced neuronal apoptosis in this model. These results confirmed the hypothesis that manipulations of intracellular pool of zinc by zinc-chelating agents may be a cause of both induction and prevention of apoptotic cell death in various pathological conditions.

Chronic excitotoxicity mediated through defective glial and/or neuronal glutamate transport may contribute to several neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). This study was performed to determine the ultrastructural characteristics of astroglial changes concomitant with motor neuron (MN) degeneration in a model of slow excitotoxicity in vitro. The study was performed on organotypic cultures of rat lumbar spinal cord subjected to the glutamate uptake blockers threohydroxyaspartate (THA) and L-trans-pyrrolidine-2,4-dicarboxylate (PDC). The chronic inhibition of glutamate transport by THA and PDC resulted in slow degeneration of the rat's MNs accompanied by distinct glial changes predominantly involving protoplasmic astrocytes. The presence of irregular vacuoles and vesicles in the astroglial cells was frequently observed. Occasionally the astrocytes exhibited proliferation and accumulation of abnormal profiles of smooth endoplasmic reticulum. In 3 weeks there were no signs of increased production of glial filaments in the protoplasmic astrocytes. The results evidenced the coexistence of neuronal degeneration and astroglial abnormalities in an ALS model in vitro and suggested an active role of astrocytes contributing to the induction and propagation of MN degeneration.

There has been growing evidence that different modes of cell death exist, among them the apoptosis is thought to be an important mechanism of nerve cell loss implicated in various pathological states. A number of proteins mediated with apoptotic process have been identified, including p53, BAX, BCL-2 and BCL-X. We examined the expression of proteins related to programmed cell death in hippocampal neurons in vitro, exposed to pure anoxia or pretreated with apoptosis modulating agents: zinc and zinc chelator - TPEN. The results evidenced the noticeable differences in the expression of pro- and anti-apoptotic proteins in particular experiments. In the cultures exposed to pure anoxia, a significant increase of p53 and BAX immunoreactivity, associated with the decreased level of BCL-2 and BCL-X immunopositive cells was observed, related to the activation of apoptotic process. Hippocampal cultures pretreated with ZnCl2 before anoxia showed decreased immunoreactivity for p53 and BAX, connected with BCL-2 overexpression, whereas the cultures exposed to zinc chelating agent - TPEN or TPEN connected with anoxia showed significant increase of immunorectivity for p53 and BAX. This strong immunoreactivity of proapototic proteins (p53 and BAX) in hippocampal cultures exposed to anoxia or/and TPEN correlated with previous ultrastructural evidences of anoxia- and TPEN-induced apoptosis, while the overexpression of anti-apoptotic protein (BCL-2 and BCL-X) in zinc-pretreated cultures evidenced the protective ability of this metal against apoptosis in model of anoxia in vitro.

The defective glial and/or neuronal glutamate transport may, in chronic neurotoxicity, contribute to several neurodegenerative diseases including amyotrophic lateral sclerosis (ALS)--a progressive neurodegenerative disorder of lower and upper motor neurons (MNs). To determine the detailed ultrastructural characteristics of excitotoxic motor neurons neurodegeneration we used a model of slow excitotoxicity in vitro based on selective inhibition of glutamate uptake. The study was performed on organotypic cultures of the rat lumbar spinal cord subjected to various concentrations of glutamate uptake blockers: threohydroxyaspartate (THA) and L-trans-pyrrolidine-2, 4-dicarboxylate (PDC). The chronic inhibition of glutamate transport resulted in a dose-dependent slow neurodegeneration of spinal MNs consisting of necrotic, apoptotic and autophagic mode of cell death. There were some MNs that shared certain characteristics of a different type of cell injury. The results showed that a different mode of cell death in excitotoxic MNs degeneration may coexist resulting in apoptosis-necrosis and apoptosis-autophagocytosis continuum.

Malignant peripheral nerve sheath tumours (MPNSTs) are rare soft tissue neoplasms arising from elements of the nerve sheath that often occur in the context of neurofibromatosis (NF) type 1. Their poor prognosis results from high local recurrence rate and distant dissemination. Nevertheless, the brain metastases are exceptional. We are presenting an unusual case of intrathoracic MPNST in a 33-year-old man with a five-year clinical course characterised by multiple times local recurrences of primary tumour and multiple remote metastases into the brain structures, thyroid and suprarenal gland. Moreover, the cerebellar metastasis regrew in spite of its total excision. Histologically, brain metastatic tumours were composed of spindle cells closely arranged in interlacing and woven fascicles. This highly cellular nerve tissue exhibited an advanced nuclear hyperchromasia and a high mitotic activity. The tumour exhibited rich delicate reticulin network. The schwannian nature of brain metastases has been confirmed by immunohistochemical findings showing S-100 protein and GFAP expression and ultrastructural evidences of the pericellular basal lamina.

An exceptional case of a recurrent intracranial ependymoma of myxopapillary type arising from the lateral ventricle is reported in a 37-year-old man. This distinctive morphological variant of ependymoma is virtually restricted to the region of cauda equina and filum terminale or occasionally to pre- or post-sacral soft tissue. The intracranial cases of myxopapillary ependymoma are extremely rare and are generally associated with the primary ependymal tumour at the typical lumbosacral site. This case of intraventricular myxopapillary ependymoma did not demonstrate any MRI evidence of a primary spinal cord tumour. Moreover, the initial diagnosis of this histologically benign tumour was followed by two tumour recurrences during the three-year follow-up period. To our knowledge, this is the third documented case of a primary intraventricular myxopapillary ependymoma and the first one of intracranial localisation associated with local recurrences.

Pleomorphic xanthoastrocytoma (PXA) is a rare variant of a superficial cerebral astrocytoma characterised by distinct clinical and histological features. Its derivation from subpial astrocytes has been proposed, although the capacity of neoplastic cells for expression of different immunohistochemical markers is still under debate. These immunohistochemical studies were performed on eight cases of PXA in order to evaluate the expression and co-expression of glial and macrophage/histiocytic markers in various tumour cell populations. The expression of antigens was examined with the use of single- and double-immunolabelling methods for GFAP, vimentin, LCA, CD68, HLA-class II and MAC 387. All the cases of PXA showed variable immunoreactivity to GFAP, both in spindle-shaped and pleomorphic lipidised tumour cells. A subset of neoplastic cells was stained strongly with HLA-class II monoclonal antibody and with antibody to CD68. The reactivity to LCA and MAC 387 was absent in neoplastic cells, while it was easily evidenced in the non-neoplastic infiltrative component. The immunohistochemical double staining demonstrated the co-expression of GFAP and HLA-class II or CD68 antigens in the cytoplasm of individual neoplastic cells, including large pleomorphic, lipid-laden ones. It seems that tumour cells in PXAs derived from subpial astrocytes reveal monocyte/macrophage immunophenotype and demonstrate the capability of functional behaviour as mesenchymal cells with phagocytic activities. The variability in expression of antigens related to glial and monocytic/macrophage differentiation stressed the immunophenotypic heterogeneity of tumour cells in PXAs.

Increasing evidence suggests that two distinct modes of cell death, known as apoptosis and necrosis, are involved in many different pathological states. The morphological pattern of postanoxic changes has been widely studied in various experimental models, however the exact mechanism of neuronal cell death induced by ischaemic/anoxic insult is still not fully understood. The aim of this study was to determine the detailed ultrastructural criteria of postanoxic neuronal changes in in vitro model of anoxia. The electron-microscopic examination of organotypic cultures of rat hippocampus, exposed to 10- and 20-minute anoxic insult, revealed the morphological features typical for both necrotic and apoptotic neuronal cell death. Numerous neurones revealed a typical picture of passive necrotic lysis, such as advanced swelling of intracellular organelles associated with cell membrane disruption, whereas others clearly reflected an active apoptotic form of cell injury, consisting of condensation of nuclear chromatin with early preservation of cell membranes. However, there was also a subset of damaged cells sharing several features typical for both necrosis and apoptosis. These results add additional evidence to the previous studies suggesting not only that neurones injured by anoxic insult can die in a pure necrotic or apoptotic way but also that a continuum might exist between apoptosis and necrosis in certain pathological conditions.

Five cases of anaplastic oligodendrogliomas containing numerous GFAP-positive cells have been analysed by electron microscopy to establish the fine structural characteristics of neoplastic cells. Ultrastructurally, all tumours have revealed monotonous appearance typical of oligodendrogliomas, however some structural variability, particularly with reference to astrocytic differentiation, has been observed. The majority of neoplastic cells have shown the fine structural features of oligodendrocytes, accompanied by various numbers of intermediate cytoplasmic filaments. These filaments have been usually distributed in the perinuclear, less often in the peripheral, parts of the cytoplasm. The cells exhibiting features common to both oligodendroglial and astroglial cells might be regarded as an intermediate morphological form between these two cell types. True neoplastic astrocytes could be encountered only sporadically. The present electron microscopic studysupports the opinion that GFAP-positive oligodendroglial tumours contain heterogeneous neoplastic cell populations with the transitional cell types between oligodendroglial and astroglial lineage.

The subject of this study is a case of anaplastic ependymoma originally arising from the central canal of the lower spinal cord followed by the 13 years history of events of upper spinal dissemination and retrograde intracranial spread. The specimens from four subsequent surgeries generally displayed the same microscopic features of neoplastic tissue and were consistent with the diagnosis of anaplastic ependymoma. The histological diagnosis was based upon the high cellularity, considerable nuclear atypia and pleomorphism, brisk mitotic activity, focally exhibited vascular endothelial proliferation and extensive necrosis. Apart from the typical pattern of ependymoma, the tumors contained areas composed almost entirely of large, uniform clear cells or pseudogemistocytes indicating the morphological heterogeneity of neoplastic cells population. The surgical specimens from four surgical resections shared light microscopic similarities suggesting spinal and intracranial dissemination from the primary spinal tumor. Since the retrograde spread via the cerebrospinal fluid (CSF) pathway is extremely rare, the authors of this study discuss the mechanism of such way of tumor metastases.

An unusual case of a giant intraspinal schwannoma in a 45-year-old woman with 14-year history of preoperative symptoms was presented. MRI of the spine revealed an intradural, extramedullary tumor extending from the intervertebral space C4/C5 to T4 vertebral body level (2 x 1.2 x 12 cm) and filling almost the entire spinal canal. Microscopical examination showed a typical neurinoma pattern with two distinct zones of Antoni A and Antoni B tissue. Some areas exhibited nuclear atypia and hyperchromasia reflecting the degenerative changes in this slowly growing nerve sheath tumor. A rich pericellular reticulin network was seen in the areas composed of Antoni A tissue. Immunohistochemically, the tumor cells were strongly positive for S-100 protein. The diagnostic difficulties in the presented case of longstanding schwannoma resulted in the late surgical treatment. The importance of the early diagnosis of spinal nerve sheath tumors for the patient's quick recovery is stressed.