The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform
Zeng Wensheng - One of the best experts on this subject based on the ideXlab platform.
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repair of skull defect treated with self skull External Lamina
Journal of Gannan Medical University, 2007Co-Authors: Zeng WenshengAbstract:Objective:To discuss the clinic applications to the repair of skull defect with self skull External Lamina.Methods:The skull defect is repaired by using the home-made tools to acquire skull External Lamina ,according to the size of the defect.Results:It is safe and secure to acquire the skull External Lamina by using the home-made tools.20 patients with different sizes of skull defect were successfully treated with self External Lamina,with satisfied outlook and good fixation and no complications.Its tissue compatibility,stability,security is good.Conclusion:The method of repairing skull defect by self skull External Lamina is with good effect and worth promoting.
Robert A Erlandson - One of the best experts on this subject based on the ideXlab platform.
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Low grade malignant peripheral nerve sheath tumor with smooth muscle differentiation
Acta Neuropathologica, 2007Co-Authors: Fausto J. Rodriguez, Bernd W. Scheithauer, Patrice C. Abell-aleff, Elshami Elamin, Robert A ErlandsonAbstract:Malignant peripheral nerve sheath tumors are usually Schwann cell derived. Differentiation along mesenchymal lines is uncommon. Herein we present an example with smooth muscle differentiation occurring in the left distal forearm of a 62-year-old male with neurofibromatosis type I. Incisional biopsy of the slowly growing mass demonstrated a low-grade malignant peripheral nerve sheath tumor with strong S-100 protein immunoexpression as well as focal smooth muscle actin staining in atypical neoplastic cells. Immunostains for epithelial membrane antigen, neurofilament protein, glial fibrillary acidic protein, CD57, desmin, and myogenin were negative. The MIB-1 labeling index was 5.4%. Electron microscopy revealed arrays of microfilaments (actin myofilaments) variably associated with fusiform dense bodies, plasmalemmal micropinocytotic vesicles, and foci of External Lamina (basement membrane) consistent with smooth muscle differentiation. Smooth muscle should be added to the spectrum of differentiation exhibited by malignant peripheral nerve sheath tumors. Its recognition requires exclusion of the alternative diagnosis of leiomyosarcoma.
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immunohistochemical and ultrastructural comparative study of External Lamina structure in 31 cases of cellular classical and melanotic schwannomas
Applied Immunohistochemistry & Molecular Morphology, 2004Co-Authors: Hsuanying Huang, Naeun Park, Robert A Erlandson, Cristina R AntonescuAbstract:Unlike most soft tissue tumors, schwannoma is characterized by the presence of distinct linear, frequently duplicated External Lamina (EL). Although electron microscopy remains the gold standard for demonstrating this unique feature and distinguishing its morphologic variants from mimickers, the use of two anti-EL antibodies, laminin and type IV collagen, appears to supersede electron microscopy in terms of current practice. To determine whether immunohistochemical expression correlates with ultrastructural findings, 10 cellular schwannomas, 18 classic schwannomas, and 3 melanotic schwannomas were evaluated ultrastructurally and immunohistochemically using antibodies to type IV collagen and laminin. Immunohistochemically, a moderate to strong intensity in more than 50% of tumor cells was detected using either antibody in most cases of cellular schwannomas (70%), the Antoni A areas of classic schwannomas (78%), and melanotic schwannomas (67%). Ultrastructurally, the presence of diffusely continuous, duplicated EL was observed in 30% of cellular schwannomas and 56% of classic schwannomas, while 50% of cellular schwannomas and 22% of classic schwannomas showed either continuous simple EL or discontinuous but duplicated EL alone. In addition, two cellular schwannomas (20%) and four classic schwannomas (22.2%) had only a simple layer of EL in focal areas. In contrast to the distinct immunostaining surrounding individual cells seen in the former two subtypes, all three melanotic schwannomas displayed a biphasic-staining pattern of the EL (ie, individual cell and nested), which was confirmed at the ultrastructural level. The authors found a significant difference in intensity between the Antoni A and B areas of classic schwannomas using both laminin and type IV collagen. In addition, the intensities of laminin and type IV collagen in the Antoni A areas of classic schwannomas were significantly stronger compared with those of cellular schwannomas. Nevertheless, there was no significant difference either between two antibodies or between cellular and classic variants with regard to the extent of immunoreaction. Only in classic schwannomas did the extent of immunoreaction against both laminin and type IV collagen correlate significantly with the ultrastructural EL distribution pattern (diffusely continuous vs. discontinuous). However, this association was not detected in cases of cellular schwannomas. On the other hand, the intensities of laminin and type IV collagen did not correlate with the ultrastructural thickness of EL, irrespective of the morphologic subtypes. In conclusion, both type collagen IV and laminin are still reliable markers of EL in various types of schwannomas. Schwannomas exhibiting a monolayered EL are as strong in immunoreaction as those displaying reduplicated/thickened EL, indicating that a single layer of EL is thick enough to be identified by both antibodies with sufficient sensitivity. The peculiar biphasic EL pattern seen in melanotic schwannoma remains under-recognized, which may lead to misdiagnosis as malignant melanomas, especially in limited biopsy specimens.
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The enigmatic perineurial cell and its participation in tumors and in tumorlike entities.
Ultrastructural Pathology, 1991Co-Authors: Robert A ErlandsonAbstract:The perineurial cells that make up the perineurium of peripheral nerve fascicles are characterized by distinct ultrastructural features, including non-branching thin cytoplasmic processes coated by an External Lamina and joined at their ends by a tight junction, few organelles, actin and vimentin filaments, and numerous pinocytotic vesicles. Perineurial cells are immunoreactive for vimentin and epithelial membrane antigen (EMA) but not for the Schwann cell markers S-100 protein and Leu-7. The cytogenesis of the perineurium remains disputable, with morphologic, immunohistochemical, and experimental evidence supporting origin from the fibroblast, Schwann cell, and arachnoid cap cell. Ultrastructural studies more recently supported by immunolocalization of EMA have detected hyperplastic and neoplastic perineuriallike cells in a number of pseudoneoplastic lesions and true neoplasms, notably localized hypertrophic neuropathy, neurofibromas of various types, and perineurioma.
Brian P Eyden - One of the best experts on this subject based on the ideXlab platform.
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Intranodal myofibroblastoma: study of a case suggesting smooth-muscle differentiation.
Journal of submicroscopic cytology and pathology, 2020Co-Authors: Brian P Eyden, Katherine ChorneykoAbstract:Abstract A case of intranodal myofibroblastoma with amianthoid fibres was studied by histology, immunohistochemistry and electron microscopy, in a Canadian Caucasian male presenting with an inguinal mass which appeared following a sports injury. Tumour cells were spindled and formed haphazard interlacing fascicles with intervening areas of haemorrhage. They were positive for vimentin, alpha-smooth-muscle actin and HHF35. By electron microscopy, they displayed moderate numbers of rough endoplasmic reticulum cisternae, fine actin-sized filaments in cell processes, and discrete stretches of unambiguous Lamina ('External' Lamina), sometimes in association with short attachment plaques. The fibronectin fibrils and fibronexus junctions characteristic of myofibroblasts were not seen. The absence of fibronexus junctions and the presence of surface features typical of smooth-muscle cells (attachment plaques with overlying Lamina) suggest that this tumour is not myofibroblastic but is exhibiting a degree of smooth-muscle differentiation. The findings confirm earlier observations suggesting that some intranodal myofibroblastomas are not myofibroblastic, but show a form of smooth-muscle differentiation.
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a structure resembing basal External Lamina on the surface of plasma cells and a discussion on intercellular contacts between hemolymphoid cells
Ultrastructural Pathology, 2009Co-Authors: Brian P EydenAbstract:Basal/External Lamina is not found over plasma cells or other hemolymphoid cells, and the feature can have diagnostic value in distinguishing the neoplastic counterparts of such cells from epithelium, endothelium, mesothelium, and so on, which do have this feature. In this paper, a material ultrastructurally indistinguishable from basal or External Lamina is reported on reactive plasma cells found in a fibrous pseudotumor, intralobular stroma of normal breast, tumor stroma of squamous cell carcinoma, and submucosa of normal human small intestine. It was focal, followed the contours of the cell-surface membrane, was lightly textured, 40–80 nm thick, and separated from the plasma cell surface membrane by a clear space resembling a Lamina lucida. Its function remains uncertain, although it may implement adhesion to other cells, as part of the immune functions that plasma cells and other hemolymphoid cells perform in the gut, for example, and elsewhere.
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A Structure Resembing Basal/External Lamina on the Surface of Plasma Cells, and a Discussion on Intercellular Contacts Between Hemolymphoid Cells
Ultrastructural Pathology, 2009Co-Authors: Brian P EydenAbstract:Basal/External Lamina is not found over plasma cells or other hemolymphoid cells, and the feature can have diagnostic value in distinguishing the neoplastic counterparts of such cells from epithelium, endothelium, mesothelium, and so on, which do have this feature. In this paper, a material ultrastructurally indistinguishable from basal or External Lamina is reported on reactive plasma cells found in a fibrous pseudotumor, intralobular stroma of normal breast, tumor stroma of squamous cell carcinoma, and submucosa of normal human small intestine. It was focal, followed the contours of the cell-surface membrane, was lightly textured, 40–80 nm thick, and separated from the plasma cell surface membrane by a clear space resembling a Lamina lucida. Its function remains uncertain, although it may implement adhesion to other cells, as part of the immune functions that plasma cells and other hemolymphoid cells perform in the gut, for example, and elsewhere.
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Intranodal Myofibroblastoma: Report of a Case
Ultrastructural Pathology, 2009Co-Authors: Brian P Eyden, Martin Harris, Godman I. N. Greywoode, L Christensen, S. Sankar BanerjeeAbstract:Palisaded myofibroblastoma (hemorrhagic spindle cell tumor) is a recent addition to the group of benign primary spindle cell lesions of lymph nodes. These tumors are characterized histologically by hemorrhage, palisading, and foci of collagen called amianthoid fibers. We report a further typical example with the aim of discussing its differentiation. Tumor cells were positive for smooth-muscle actin and vimentin. The cytoplasm contained moderate numbers of rough endoplasmic reticulum cisternae and some smooth-muscle type myofilaments. Sub-plasmalemmal densities and plasmalemmal caveolae, as well as material interpreted as External Lamina, were identified at the cell surface, whereas the fibronexus junctions typical of myofibroblasts were not seen. Immunostaining for type IV collagen was positive. Intranodal myofibroblastomas have largely been considered as myofibroblastic, but the observations presented here raise the alternative possibility of simple smooth-muscle differentiation. The foci of collagen wi...
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Leiomyosarcoma versus myofibrosarcoma: observations and terminology.
Ultrastructural Pathology, 1993Co-Authors: Brian P Eyden, L ChristensenAbstract:: Two spindle cell sarcomas, which showed similarities in light microscopic histology and immunostaining and were diagnosed as leiomyosarcomas by these criteria, were compared ultrastructurally to show the value of electron microscopy in subtyping these neoplasms. Both were subcutaneous, case 1 occurring in the nasolabial fold and case 2 in the upper calf. Both consisted of fascicles of spindle cells, and both stained positively for vimentin and alpha-smooth muscle actin; only case 2 stained additionally for desmin. Case 1 showed strong and case 2 weak or negative staining for fibronectin. By electron microscopy, case 1 contained prominent rough endoplasmic reticulum, peripheral fine filaments with focal densities, and fibronexus junctions. By contrast, case 2 was characterized by an External Lamina and well-developed bundles of fine filaments with focal densities. Case 2 was considered a typical leiomyosarcoma, and case 1 was interpreted as showing myofibroblastic differentiation. The nomenclature for these myofibroblastic tumors is discussed, and myofibrosarcoma and leiomyosarcoma, myofibroblastic variant are suggested as suitable terms.
Cristina R Antonescu - One of the best experts on this subject based on the ideXlab platform.
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immunohistochemical and ultrastructural comparative study of External Lamina structure in 31 cases of cellular classical and melanotic schwannomas
Applied Immunohistochemistry & Molecular Morphology, 2004Co-Authors: Hsuanying Huang, Naeun Park, Robert A Erlandson, Cristina R AntonescuAbstract:Unlike most soft tissue tumors, schwannoma is characterized by the presence of distinct linear, frequently duplicated External Lamina (EL). Although electron microscopy remains the gold standard for demonstrating this unique feature and distinguishing its morphologic variants from mimickers, the use of two anti-EL antibodies, laminin and type IV collagen, appears to supersede electron microscopy in terms of current practice. To determine whether immunohistochemical expression correlates with ultrastructural findings, 10 cellular schwannomas, 18 classic schwannomas, and 3 melanotic schwannomas were evaluated ultrastructurally and immunohistochemically using antibodies to type IV collagen and laminin. Immunohistochemically, a moderate to strong intensity in more than 50% of tumor cells was detected using either antibody in most cases of cellular schwannomas (70%), the Antoni A areas of classic schwannomas (78%), and melanotic schwannomas (67%). Ultrastructurally, the presence of diffusely continuous, duplicated EL was observed in 30% of cellular schwannomas and 56% of classic schwannomas, while 50% of cellular schwannomas and 22% of classic schwannomas showed either continuous simple EL or discontinuous but duplicated EL alone. In addition, two cellular schwannomas (20%) and four classic schwannomas (22.2%) had only a simple layer of EL in focal areas. In contrast to the distinct immunostaining surrounding individual cells seen in the former two subtypes, all three melanotic schwannomas displayed a biphasic-staining pattern of the EL (ie, individual cell and nested), which was confirmed at the ultrastructural level. The authors found a significant difference in intensity between the Antoni A and B areas of classic schwannomas using both laminin and type IV collagen. In addition, the intensities of laminin and type IV collagen in the Antoni A areas of classic schwannomas were significantly stronger compared with those of cellular schwannomas. Nevertheless, there was no significant difference either between two antibodies or between cellular and classic variants with regard to the extent of immunoreaction. Only in classic schwannomas did the extent of immunoreaction against both laminin and type IV collagen correlate significantly with the ultrastructural EL distribution pattern (diffusely continuous vs. discontinuous). However, this association was not detected in cases of cellular schwannomas. On the other hand, the intensities of laminin and type IV collagen did not correlate with the ultrastructural thickness of EL, irrespective of the morphologic subtypes. In conclusion, both type collagen IV and laminin are still reliable markers of EL in various types of schwannomas. Schwannomas exhibiting a monolayered EL are as strong in immunoreaction as those displaying reduplicated/thickened EL, indicating that a single layer of EL is thick enough to be identified by both antibodies with sufficient sensitivity. The peculiar biphasic EL pattern seen in melanotic schwannoma remains under-recognized, which may lead to misdiagnosis as malignant melanomas, especially in limited biopsy specimens.
Hsuanying Huang - One of the best experts on this subject based on the ideXlab platform.
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immunohistochemical and ultrastructural comparative study of External Lamina structure in 31 cases of cellular classical and melanotic schwannomas
Applied Immunohistochemistry & Molecular Morphology, 2004Co-Authors: Hsuanying Huang, Naeun Park, Robert A Erlandson, Cristina R AntonescuAbstract:Unlike most soft tissue tumors, schwannoma is characterized by the presence of distinct linear, frequently duplicated External Lamina (EL). Although electron microscopy remains the gold standard for demonstrating this unique feature and distinguishing its morphologic variants from mimickers, the use of two anti-EL antibodies, laminin and type IV collagen, appears to supersede electron microscopy in terms of current practice. To determine whether immunohistochemical expression correlates with ultrastructural findings, 10 cellular schwannomas, 18 classic schwannomas, and 3 melanotic schwannomas were evaluated ultrastructurally and immunohistochemically using antibodies to type IV collagen and laminin. Immunohistochemically, a moderate to strong intensity in more than 50% of tumor cells was detected using either antibody in most cases of cellular schwannomas (70%), the Antoni A areas of classic schwannomas (78%), and melanotic schwannomas (67%). Ultrastructurally, the presence of diffusely continuous, duplicated EL was observed in 30% of cellular schwannomas and 56% of classic schwannomas, while 50% of cellular schwannomas and 22% of classic schwannomas showed either continuous simple EL or discontinuous but duplicated EL alone. In addition, two cellular schwannomas (20%) and four classic schwannomas (22.2%) had only a simple layer of EL in focal areas. In contrast to the distinct immunostaining surrounding individual cells seen in the former two subtypes, all three melanotic schwannomas displayed a biphasic-staining pattern of the EL (ie, individual cell and nested), which was confirmed at the ultrastructural level. The authors found a significant difference in intensity between the Antoni A and B areas of classic schwannomas using both laminin and type IV collagen. In addition, the intensities of laminin and type IV collagen in the Antoni A areas of classic schwannomas were significantly stronger compared with those of cellular schwannomas. Nevertheless, there was no significant difference either between two antibodies or between cellular and classic variants with regard to the extent of immunoreaction. Only in classic schwannomas did the extent of immunoreaction against both laminin and type IV collagen correlate significantly with the ultrastructural EL distribution pattern (diffusely continuous vs. discontinuous). However, this association was not detected in cases of cellular schwannomas. On the other hand, the intensities of laminin and type IV collagen did not correlate with the ultrastructural thickness of EL, irrespective of the morphologic subtypes. In conclusion, both type collagen IV and laminin are still reliable markers of EL in various types of schwannomas. Schwannomas exhibiting a monolayered EL are as strong in immunoreaction as those displaying reduplicated/thickened EL, indicating that a single layer of EL is thick enough to be identified by both antibodies with sufficient sensitivity. The peculiar biphasic EL pattern seen in melanotic schwannoma remains under-recognized, which may lead to misdiagnosis as malignant melanomas, especially in limited biopsy specimens.
