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  • 1
    ISSN: 1432-0533
    Keywords: Neurofibromatosis 2 ; Bilateral acoustic neurofibromatosis ; Ghal hamartomas ; Immunohistochemistry ; S-100 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bilateral acoustic neurofibromatosis (neurofibromatosis 2, NF2) accounts for less than 10% of all cases of neurofibromatosis and manifests itself with bilateral acoustic schwannomas, multiple schwannomas of spinal nerve roots, meningiomas, glial tumors and hamartomatous CNS lesions. We have observed dysplastic foci of immature neuroectodermal cells in the cerebral cortex and basal ganglia of six patients afflicted with neurofibromatosis 2, ranging from occasional clusters of immature, dysplastic cells to numerous, confluent lesions. These cells, although often polymorphic and multinuclear did not show mitotic acitivity or a tendency for neoplastic transformation. To determine the histogenesis of these foci, extensive immunocytochemical reactions were carried out with antibodies to a variety of glial, neuronal and nonneural cell lineages. With the exception of S-100 protein, no immunoreactivity was detectable. S-100 was consistently expressed in these foci, irrespective of their size, location, and degree of polymorphism. On the basis of cytological appearance, distribution and immunoreactivity we tentatively designate these foci as glial micro-hamartomas. Although we did not systematically analyze the CNS of patients with von Recklinghausen neurofibromatosis (neurofibromatosis 1, NF1), the present study strongly suggests that these micro-hamartomas constitute a morphological hallmark of bilateral acoustic neurofibromatosis (NF2).
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Der Pathologe 19 (1998), S. 259-268 
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Gliom ; Astrozytom ; Oligodendrogliom ; Grading ; Überlebenszeitanalyse ; Key words Glioma ; Astrocytoma ; Oligodendroglioma ; Grading ; Survival analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The histologic determination of the degree of tissue anaplasia and grade of malignancy of gliomas is based upon qualitative histological features (nuclear pleomorphism, mitoses, endothelial proliferation, tumor necrosis). This grading approach is influenced by the subjective interpretation of the pathologist, especially concerning the weighting of criteria (scant, moderate, pronounced). An observer-independent approach seems to be feasible by abandoning the concept of parameter weighting in favor of an binary approach noting only the presence or absence of these structure parameters. This grading procedure is recognized in the revised WHO classification of brain tumors for common type astrocytomas (Ste. Anne-Mayo System, SAMS). Our results indicate that a similiar approach is also suitable for grading purposes of oligodendrogliomas and mixed gliomas. Our recent investigations on glioma grading showed, both for astrocytomas and oligodendrogliomas, that a two-tiered grading scheme distinguishing only ”low-grade” and ”high-grade” cases was prognostically relevant. For all glioma entities the onset of tumor angiogenesis with endothelial proliferation and contrast enhancement in CT and MRI seems to be the key criterion indicating irreversible tumor progression to the ”high” malignancy grade.
    Notes: Zusammenfassung Die histologische Bestimmung des Anaplasiegrades von Gliomen wird nach qualitativen histologischen Merkmalen (Kernpleomorphie, Mitosen, Endothelproliferate, Tumornekrosen) vorgenommen und mit dem Malignitätsgrad gleichgesetzt. Vor allem die Wichtung dieser Merkmale (”gering – mittel – stark ausgeprägt”) unterliegt dem subjektiven Eindruck des jeweiligen Befunders. Um eine höhere Reproduzierbarkeit der Gradingbeurteilung zu erreichen, wurde auf die Wichtung verzichtet und lediglich das Vorhandensein oder Fehlen dieser vier definierten qualitativen Kriterien verzeichnet. Es hat sich gezeigt, daß durch dieses binäre System eine verläßlichere Aussage über die Dignität von Gliomen möglich ist (Ste. Anne-Mayo-System, SAMS). Neuere Untersuchungen belegen, daß auch für das Grading der Oligodendrogliome und der Mischgliome ein ähnliches binäres System praktikabel ist, wobei sowohl für die Astrozytome als auch für die Oligodendrogliome die Unterscheidung einer niedrigen und hohen Risikogruppe über das Fehlen oder Vorhandensein von Endothelproliferaten durchgeführt wird. Die Endothelproliferate ihrerseits – als Zeichen einer in Gang gekommenen Tumorangiogenese – korrelieren mit der Kontrastmittelanreicherung bei der kranialen Computer- und Kernspintomographie.
    Type of Medium: Electronic Resource
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