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  • 1
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aim : To document the clinical, histological, immunohistochemical and ultrastructural features of three malignant melanomas showing neuroendocrine differentiation.Methods and results : Three patients, two with primary cutaneous melanoma and one with nasal mucosal melanoma, subsequently developing or simultaneously presenting with metastatic malignant melanoma, were studied by conventional histological technique, immunohistochemistry of formalin-fixed paraffin-wax embedded tissues, and electron microscopy of epoxy-resin-embedded tumour tissue. Tumours showed either small cell or conventional malignant melanoma cell morphology. One of the three primary melanocytic lesions (the nasal melanoma) exhibited neuroendocrine differentiation immunohistochemically. All three metastatic malignant melanomas showed, in varying combinations, immunohistochemical and ultrastructural evidence for neuroendocrine differentiation: they were positive for the melanocytic markers, S100 protein, HMB-45, Melan-A and tyrosinase, and the neuroendocrine markers chromogranin, synaptophysin and neurofilament protein. Ultrastructural study in two of the metastases revealed neuroendocrine granules but no lattice-bearing melanosomes.Conclusions : The cases described are the most comprehensively investigated malignant melanomas showing neuroendocrine differentiation to date, and the first to document neuroendocrine differentiation ultrastructurally in these tumours. Malignant melanoma with neuroendocrine differentiation therefore needs to be recognized among the other, better known variants of malignant melanoma.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A study of four cases of extra-orbital giant cell angiofibroma with documentation of some unusual features Aims: To document the clinical, light microscopic, immunohistochemical and ultrastructural features of four cases of extra-orbital giant cell angiofibromas. Methods and results: Sections of formalin-fixed paraffin-embedded specimens were studied by haematoxylin and eosin, reticulin and immunohistochemical stains. Electron microscopy was carried out in two cases on tissue fixed in formalin. The age of the patients ranged from 30 to 41 years. Two patients presented with a soft tissue swelling in the left groin, one patient had a left axillary soft tissue lump and one patient presented with a parotid lump. All lesions were well circumscribed and contained variably cellular and vascularized tissue composed of round to spindle cells with a patternless arrangement, scattered multinucleate giant cells and pseudovascular spaces conforming to the description of giant cell angiofibroma. Mononuclear and multinucleate tumour cells were both positive for vimentin and CD34; one tumour exhibited focal S100 protein and GFAP positivity. Both of the tumours examined by electron microscopy showed fibroblastic features, but in addition one contained cells having Schwannian features. All four patients were well without recurrent disease on follow-up (average 25 months). Conclusion: Giant cell angiofibroma shares many features with solitary fibrous tumour and giant cell fibroblastoma and shows a wider distribution than initially recognized. Rarely, Schwannian differentiation may be observed in these tumours.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Histopathology 35 (1999), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The histopathological diagnosis of tumours has been transformed by immunohistochemistry. Used with experience and judgement, a panel of antibodies or antisera, combined when necessary with antigen retrieval, will enable the accurate typing of most problematic tumours. This has led many histopathologists to question whether the electron microscope has any residual utility for tumour diagnosis; the machines are large, costly to purchase and maintain, and will accept only minute samples of tissue. The following articles by Mierau and by Eyden, both strong advocates, comment on the current and future role of electron microscopy in tumour diagnosis.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Histopathology 33 (1998), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To study the clinical and histopathological features of sclerosing epithelioid fibrosarcoma, and to define diagnostic criteria for this uncommon soft-tissue tumour.〈section xml:id="abs1-2"〉〈title type="main"〉Methods and resultsStandard histological, immunohistochemical and ultrastructural techniques were applied to five tumours from head and neck, chest wall and groin. Tumours consisted of groups of monomorphic rounded/epithelioid cells surrounded by a prominent collagenous stroma. Tumour cells showed positive vimentin staining but were negative for other markers. They contained prominent rough endoplasmic reticulum and a large Golgi apparatus which in one case was producing collagen secretion granules, an ultrastructural marker for collagen production. Three patients had medium to long-term survival (3–7 years). Of these, one was disease-free for 3 years, and two experienced multiple recurrences: one of the latter died of metastatic disease.〈section xml:id="abs1-3"〉〈title type="main"〉ConclusionCriteria for diagnosing this uncommon tumour include: small to medium cell size, clear or pale cytoplasm, cellular arrangement in cords and strands, dense collagenous stroma; vimentin staining; rough endoplasmic reticulum and a Golgi apparatus producing, in well preserved examples, collagen secretion granules. The paper emphasizes the value of electron microscopy, supporting an appropriate histological picture and immunophenotype, in identifying these relatively low-grade sarcomas.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Cancer Genetics and Cytogenetics 54 (1991), S. 267 
    ISSN: 0165-4608
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 415 (1989), S. 297-300 
    ISSN: 1432-2307
    Keywords: Non-Hodgkin's lymphoma ; Electron microscopy ; Immunohistochemistry ; Intercellular junction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A rare example of pleomorphic B cell non-Hodgkin's lymphoma is described in which tumour cells possessed simple intercellular junctions.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2307
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 417 (1990), S. 395-404 
    ISSN: 1432-2307
    Keywords: Ultrastructure ; Non-Hodgkin's lymphoma ; Signet-ring cell ; Endoplasmic reticulum ; Multivesicular body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary New ultrastructural findings are reported from two lymphomas of vacuolar signet-ring cell morphology (SR+), one of B cell and one of T cell lineage. When these lymphomas were compared ultrastructurally a difference in the relationship of the endoplasmic reticulum (ER) to the vacuole was noted, although the fine structure of the vacuoles themselves was similar and they were interpreted as giant multivesicular bodies (mvbs). Smooth ER was found near the vacuoles in both cases. Dark mvbs with a complex, reticulate form are emphasised as readily identified but hitherto unreported cell components in these tumours. A further B cell lymphoma of centroblastic/centrocytic type which was SR− was found to be rich in mvbs and may be a transitional form between SR− and SR+ lymphomas. In addition, the occurrence of mvbs has been studied quantitatively in a number of other lymphomas and in B and T lymphocytes in reactive nodes. Although increased numbers of mvbs were found in neoplastic compared with reactive lymphocytes, and in T compared with B cell lymphomas, these differences were not statistically significant. The possible roles of endoplasmic reticulum and mvbs in the generation of SR+ change are discussed.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2307
    Keywords: Leiomyoma ; Myometrium ; Cytoskeleton ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The filamentous components of the cytoskeleton in smooth muscle cells of leiomyomata and normal myometrium were studied by immunohistochemistry and electron microscopy. Fourteen patients hysterectomised for non-malignant disease provided leiomyomata of conventional histological type and histologically normal myometrium: four samples of fetal myometrium were studied by immunohistochemistry alone. All samples of leiomyoma and myometrium were strongly positive for α-smooth muscle actin and desmin, the latter often as paranuclear columns or granules. Vimentin was also stained in most samples but less intensely, while cytokeratin stained in about half the samples with an intensity comparable to that of vimentin. By electron microscopy, myofilaments with focal densities were abundant in both normal myometrium and leiomyomata. Intermediate filaments corresponding to the desmin and vimentin demonstrated by immunohistochemistry were also recognised in a variety of architectural arrangements. At one extreme, comparatively small numbers of filaments were loosely distributed around membranous organelles; at the other, filaments formed conspicuous aggregates, largely excluding other organelles and corresponding to the paranuclear granules seen by immunohistochemistry. A comparison of these findings with those of the literature and comments on the possible significance and origin of these aggregates are provided.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-2307
    Keywords: Collagen secretion granule ; Myofibroblast ; Spindle cell tumour ; Electron microscopy ; Diagnosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Collagen secretion granules, representing stages in the intracellular packaging, transport and secretion of collagen-fibril precursor, have been studied by transmission electron microscopy in non-neoplastic human myofibroblasts and in neoplastic cells from a preliminary study of tumours exclusively or partly of spindle cell type. Vesicles, newly separated from Golgi saccules and containing finely fibrillar material, were identified as early presecretory granules, the most immature type of granule. Later stages exhibited longitudinally arranged, densely fibrillar bundles. Subsequently, secretory granules developed more homogeneously dense content. Fibril-containing cisternae near the plasma membrane were interpreted as either endocytotic or lysosomal structures, or as participants in the final stages of secretion. The features by which collagen secretion granules can be distinguished from other Golgi products, in particular melanosomes, Weibel-Palade bodies and lysosomes, are pointed out. The significance of these organelles for cell identification and tumour diagnosis is discussed.
    Type of Medium: Electronic Resource
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