Cases reported "Cerebellar Neoplasms"

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1/18. Cerebral granular cell astrocytomas: a Mib-1, bcl-2, and telomerase study.

    Granular cell (GC) astrocytoma is an uncommon variant of glioma that shares the cytologic features and high cytoplasmic lysosomal content with granular cell tumors elsewhere in the body. While the histogenesis and behavior of these neoplasms was originally in dispute because most were reported as single cases, the accumulated literature on approximately three dozen such lesions has now verified their usual astrocytic lineage and poor prognosis. Although the GC cell is thought to represent a degenerative process, little is known in these tumors about cell cycle regulation, as measured by Mib-1 and bcl-2 immunolabeling, or expression of other biomarkers of malignancy, such as telomerase. In our study, GC astrocytomas were similar to gemistocytic astrocytomas in their bland histology, often prominent perivascular lymphocytic cuffing and low Mib-1 labeling indices. Like gemistocytes, GCs appear to represent senescent, non-cycling cells. Absence of significant bcl-2 immunolabeling in our three cases, however, suggests that unlike gemistocytes, GC astrocytes develop senescence by mechanisms other than bcl-2 mediated apoptosis suppression. In one case in which frozen tissue was available for assay, we noted relatively high quantitative telomerase expression. The level paralleled that seen in other glioblastomas. Demise for our three patients occurred 3-25 months post-biopsy. Like gemistocytes, the presence of non-proliferative GCs signifies severe abnormalities in cell cycle regulation and maybe hallmarks of tumors with poor prognosis.
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2/18. Dysembryoplastic neuroepithelial tumor of the cerebellum and brainstem. Case report.

    The authors present a case in which dysembryoplastic neuroepithelial tumors (DNETs) occurred in the cerebellum and brainstem of a 44-year-old woman. A magnetic resonance image of the brain revealed multiple cystic lesions in the right cerebellar hemisphere, vermis, tonsil, and brainstem. Partial removal of the tumors was performed. There were gray multinodular gelatinous lesions on the cerebellar hemisphere. Histologically, the tumors exhibited areas of multiple microcystic nodules in the cerebellar white matter, which were composed of oligodendroglia-like cells (OLCs), astrocytes, and neurons. There were multiple, variable nodules in the lesions, lined by OLCs. The adjacent cerebellar cortex displayed dysplastic features. Reduction of granule neurons and dislocation of purkinje cells into the molecular layer were observed. The pathological profile of this patient agrees with that described by Daumas-Duport, et al., as a "dysembryoplastic neuroepithelial tumor."
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3/18. hemosiderin pigmentation of tumour cells in cerebellar pilocytic astrocytoma associated with post-traumatic hemorrhage in adults.

    The pilocytic astrocytoma is only rarely associated with gross intratumoral hemorrhage despite rich vasculature and blood vessel changes, accompanied often by perivascular depots of hemosiderin. We report an unusual case of pigmented cerebellar pilocytic astrocytoma presenting with posttraumatic hemorrhage in a 38-year-old man with no history related to the tumor. CT and MRI examination after head injury demonstrated unexpectedly the cystic lesion of 2 cm in diameter in the region of the right cerebellar hemisphere and vermis. The lesion was associated with hematoma and it was surgically removed 3 weeks after trauma. Histopathological examination revealed pilocytic astrocytoma tissue with broad hemorrhagic changes and with an unusual pattern of massive pigmentation of the cytoplasm of pilocytic astrocytes, consistent with hemosiderosis. Positive stains for iron and ferritin and ultrastructural study confirmed deposition of hemosiderin granules in the tumour cells. There was no evidence of melanin or melanosomes. This finding of hemosiderin accumulation in the cytoplasm of neoplastic astroglia seems to be analogous to post-hemorrhagic pigmentation of the normal Bergmann glia and subpial astrocytes. In the literature, the examples of neuroepithelial tumors with hemosiderin pigmentation of tumor cells have been rarely documented. To our knowledge, this is the first reported case of pigmented pilocytic astrocytoma exhibiting extensive intracellular hemosiderin deposition.
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4/18. Ganglioglial differentiation in medulloblastoma.

    A case of cerebellar medulloblastoma with clusters of mature ganglion cells and glial cells is described. The patient, a 15-year-old girl, underwent three operations followed each time by radiation and chemotherapy during the four-year clinical course. Histologically, the ganglion cells were clearly identifiable by their abundant eosinophilic cytoplasm, round nuclei with prominent nucleoli, tigroid granules, and argyrophilic fibrils and axons. Immunohistochemically, the cells were NSE- and NF-positive, and ultrastructurally they contained abundant tubules and filaments, neurosecretory granules and well developed rough endoplasmic reticulum. There were many cells transitional in appearance between primitive cells and mature ganglion cells. The tumor also had many mature yet atypical astrocytes and oligodendrocytes. The exact mechanism of the extensive neuronal and glial maturation of medulloblastoma cells is unclear, but the repetitive surgical interventions, radiation and chemotherapy might have had certain cytostatic effects on rapidly dividing medulloblastoma cells, giving them a chance to mature into postmitotic cells with potential for neuronal and glial differentiation.
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5/18. Rod-shaped filamentous inclusions and other ultrastructural features in a cerebellar astrocytoma.

    A biopsy specimen of a cerebellar astrocytoma from a 14-year-old girl was studied by light and electron microscopy. Histologically the tumor showed a mixture of loose and compact areas with numerous Rosenthal fibers. By electron microscopy most tumor cells contained, besides the usual organelles, large amounts of 70 to 100 A thick filaments. Classical Rosenthal fibers were also identified. In addition many cell bodies and processes were sprinkled with fragments of Rosenthal fiber material. Ordered filamentous arrays (so-called Hirano bodies) were seen in a number of tumor astrocytes. They are considered to be a nonspecific arrangement of filament units largely devoid of cytopathologic significance. Other ultrastructural features of some tumor cells were inchoate forms of the granulated bodies of conventional histology, paired cisternal elements of rough endoplasmic reticulum, and honeycomb-like profiles of transversely cut cylindrical units of smooth endoplasmic reticulum. Microtubular bodies were numerous in the endothelial cells of the tumor vessels.
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6/18. Melanotic neuroectodermal tumors of the brain and skull.

    A case of melanotic neuroectodermal tumor in the cerebellum of a 21-year-old man is presented. Melanin was found mainly in small neoplastic cells rather than in large epithelioid cells. The tumor also contained neurons, as well as neoplastic tissue of ependyma, choroid plexus; and astrocytes. We propose that this neuroectodermal tumor resulted from a combination of cells originating in the neural crest and in the neural tube. The small cells have been described as medulloblasts, but they may be poorly differentiated ependymal cells, or, sympathicoblasts. The presence of pigment in these cells is compatible with an origin in the neural crest. The so-called melanotic progonoma, occurring most often in the maxilla of infants, is reviewed in relation to the melanotic neuroectodermal tumor of the brain. The tumor in facial bone occurs in adults as well as infants, in locations other than the maxilla, and has malignant forms. Melanotic neuroectodermal tumors, whether in brain or bone, are therefore similar in behavior as well as histologic appearance. The finding of similar tumors in these different locations is readily explained embryologically.
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7/18. Dibutyryl cyclic amp induces vimentin and GFAP expression in cultured medulloblastoma cells.

    Evidence for the astrocytic lineage in medulloblastomas rests largely on the detection of the glial fibrillary acidic protein (GFAP) from which intermediate filaments (IF) specific for astrocytes are assembled. Astrocyte progenitor cells from the mouse neopallium however express another IF protein, vimentin, before they acquire GFAP in vivo and in vitro. The purpose of the current study was to determine if cells obtained from a focally GFAP-positive posterior fossa medulloblastoma previously shown to acquire GFAP in response to dibutyryl cyclic AMP (dBcAMP), also express vimentin before expressing GFAP. More than 80% of cells in the tumor section contained vimentin while fewer than 1% of cells contained GFAP; occasional clusters of malignant GFAP-positive cells and clusters of cells negative for both vimentin and GFAP were also identified in the tumor. One hundred per cent of cultured cells in the first 10 passages from the tumor contained vimentin and no cells expressed GFAP. When cells were cultured in the presence of dBcAMP. Western immunoblotting showed an increase in vimentin which reached maximal values within 24 h followed by an increase in GFAP which reached maximal values at 72 h. The increase in vimentin followed by that of GFAP in cultured medulloblastoma cells has not previously been reported and suggests that most astrocyte progenitors which are derived from medulloblastoma and cultured in vitro may be at a developmental stage which corresponds to the proastroblast stage in the developing mouse brain.(ABSTRACT TRUNCATED AT 250 WORDS)
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8/18. Cerebellar ganglioglioma in a child.

    A cerebellar ganglioglioma was surgically removed from a two-year old boy, who had developed manifestations of increased intracranial pressure and cerebellar symptoms. At surgery, the tumor presented as a firm nodular mass displacing the cerebellar cortex. By light microscopy, its architecture differed distinctly from that of hamartomatous diffuse hypertrophy of the cerebellar cortex (Lhermitte-Duclos' disease). Mature ganglion cells were grouped in clusters and linked by thick bundles of nerve cell processes. Nerve cells and processes were enmeshed in a rich network of fibrillary connective tissue. Electron microscopy disclosed typical neuronal perikarya as well as numerous asymmetric chemical synapses. The bulk of the tumor consisted of tightly grouped, (non-myelinated) nerve cell processes arranged in parallel. One of the most prominent features of the tumor consisted of numerous dilatations of these processes. The largest ones contained microfilaments, while the smaller ones were entirely filled with dense bodies (most probably derived from degenerating mitochondria). Only scattered dense core vesicles were seen, which probably did not represent neurosecretory granules. A second cell type consisted probably of astrocytes. Most neuroepithelial cell processes could not be identified with certainty as being of either neuronal or glial origin. A third cell type consisted of numerous slender cells which were probably mesenchymal. They were surrounded by a network of basement membrane which extended between the surrounding nerve cell processes.
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9/18. The modulation of astrocytic differentiation in cells derived from a medulloblastoma surgical specimen.

    Medulloblastomas are cerebellar tumors which are primarily composed of sheets of uniform, small malignant cells and may have astrocytic, neuronal or no features typical of these cell types. The assessment of astrocytic differentiation in medulloblastoma rests largely on the detection in malignant cells of glial fibrillary acidic protein (GFAP), a marker present in the later stages of normal astrocyte differentiation. It is still not known whether cells that do not contain GFAP in medulloblastomas with astrocytic differentiation correspond to highly proliferative astrocyte progenitors in maturation arrest at earlier stages of differentiation. The purpose of the current study was to examine whether cells in short term culture derived from a medulloblastoma tumor specimen with astrocytic differentiation were of the astrocytic lineage and if so, whether they represented proliferative astrocyte progenitors which would morphologically and antigenically mature in response to differentiating agents. A portion of tumor specimen from a 10-month-old child with recurrent posterior fossa medulloblastoma (RB2) that contained GFAP focally in tumor cells was grown in monolayer culture. We examined cellular structure and appearance of western immunoblotting and immunohistochemical studies for GFAP and neuron-specific enolase (NSE) in RB2 cells before and after treatment with retinoic acid (RA) and dibutyryl cyclic amp (dBcAMP). RB2 in culture consisted of small polygonal cells (93%), large flat cells (3%), and polygonal cells with cytoplasmic processes (4%). In untreated RB2, 30% of cells expressed GFAP and staining for NSE was negative. RA treatment produced flattened cells and decreased GFAP. DBcAMP reversibly induced fine cytoplasmic processes containing GFAP in 85% of cells within 96 h. Neither agent induced NSE. The results suggest that cultured cells which are derived from a medulloblastoma with astrocytic differentiation do not spontaneously differentiate but that treatment with dBcAMP suppresses proliferation, enhances cytoplasmic process formation and increases cytoplasmic GFAP. Cells in culture and in medulloblastoma tumor specimens which do not contain GFAP may represent astrocyte progenitors in maturation arrest.
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10/18. Pigmented primitive neuroectodermal tumor with multipotential differentiation in cerebellum (pigmented medullomyoblastoma). A case with light- and electron-microscopic, and immunohistochemical analysis.

    A 5-year-old girl had a midline cerebellar primitive neuroectodermal tumor (PNET) with neuronal, astrocytic, rhabdomyoblastic and melanocytic differentiation (a variant of pigmented medullomyoblastoma). The tumor recurred following surgery and radiation therapy and the child died within 6 months. autopsy revealed spread into cerebellar hemispheres, subarachnoidal space and brain stem. Neuronal differentiation was verified by electron microscopy and antiserum against neurofilament protein. Neoplastic astrocytes were identified by use of antisera to glial fibrillary acidic and S-100 proteins. Rhabdomyoblasts were identified by the use of antisera against skeletal muscle type 2 myosin and myoglobin, as well as by electron microscopy. This tumor is compared with 20 previously reported cases of cerebellar PNETs containing muscle, 2 of which showed a similar pattern of multipotential differentiation. The oncogenesis of these tumors is in dispute although origin of both the neuroectodermal and mesenchymal components from the neural crest (mesectodermal differentiation) is most widely accepted.
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