1,721,013 research outputs found
Clinicopathological characteristics, hormone receptor status and matrix metallo-proteinase-9 (MMP-9) immunohistochemical expression in spinal meningiomas
No full textMeningiomas involving the spinal meninges show a reduced tendency to recur compared to those of the intracranial compartment. Nonetheless, due to the few reports with a significant number of patients, their biological characteristics largely remain to be investigated.With the aim of clarifying the biology of these tumors, we examined in the present paper the clinicopathological features, the estrogen receptor (ER) and progesterone receptor (PR) status, as well as the Ki-67 labeling index (LI) and matrix metallo-proteinase-9 (MMP-9) expression of 58 spinal meningiomas. Ki-67 LI ranged between 1% and 5% (median: 1%); no expression of ER was found in all the cases, whereas PR immunoexpression was found in 86% of the tumors. High MMP-9 expression was encountered in 46% of meningiomas, and it was significantly correlated with the percentage of PR expression. The recurrence rate was 1.7%. The only recurred case showed high MMP-9 expression, absence of PR and low Ki-67 LI.Our findings confirm that spinal meningiomas are indolent tumors with low growth fraction and recurrence rate. In these neoplasms, high MMP-9 expression seems to be associated with the development of recurrences only in the absence of PR expression. Thus, the evaluation of both MMP-9 and PR expression might be of use in the identification of spinal meningiomas at higher risk of relapse. (C) 2012 Elsevier GmbH. All rights reserved
Osteoblastic meningiomas: clinico-pathological and immunohistochemical features of an uncommon variant
No full textOsteoblastic meningioma is a rare variant of meningioma characterized by the presence of a variable number of bone spicules within the tumor parenchyma. Its histogenesis has not been yet fully clarified. Herein we report clinical and histological findings and expression of bone matrix proteins (osteocalcin and ostepontin) observed in seven osteoblastic meningiomas. None of the cases displayed recurrences or significant re-growth after partial resection. In 5/7 cases the osseous component occurred in association with psammoma bodies and dystrophic calcification. Interestingly, foci composed of immature bone trabeculae, mineralized chondroid matrix, and osteoclasts were found in one of the two cases with no psammoma bodies or calcification, suggesting enchondral ossification. Positive staining for osteocalcin, which is a marker of terminal osteoblastic differentiation, was observed within the bone spicules in all meningiomas, but not in the chondroid mineralized matrix. On the other hand, immuno-expression of osteopontin, an early osteogenic marker, was observed in the osteoclasts and in mature and immature bone spiculae, calcification, and psammoma bodies. Even more, osteopontin was extensively expressed by the neoplastic cells of cases without calcification or psammoma bodies, suggesting acquisition of osteoblastic phenotype in these meningiomas. In conclusion, osteoblastic meningioma seems to be an indolent variant of meningiomas characterized by a slow growth and good prognosis. Our histological and immunohistochemical findings suggest that bone formation may occur through two different pathways, i.e., as the final step of calcification or through a metaplastic mechanism in cases with absent calcification or psammoma bodies
Histopathological features to define atypical meningioma: What does really matter for prognosis?
No full textAtypical meningiomas are diagnosed in the presence of: (1) three or more of the following minor atypical criteria: increased cellularity, small cells with a high nuclear/cytoplasmic ratio, prominent nucleoli, sheeting, and foci of spontaneous or geographic necrosis; (2) mitotic count ≥ 4 mitoses per 10 HPF (high mitotic index); (3) brain invasion. The 5-year disease-free survival (DFS) is around 50%. Due to their heterogeneous behavior, the post-surgical treatment of atypical meningiomas is controversial. This study investigated the ability of histopathological features to predict recurrence risk of atypical meningiomas. Meningiomas classified as atypical only on minor atypical criteria had low recurrence risk. Brain invasion, high mitotic index and sheeting were significantly associated with shorter disease-free survival (DFS) (P = 0.001; P = 0.01; P = 0.01). The presence of brain invasion and the co-presence of sheeting and high mitotic index had the highest ability to identify recurring meningiomas (P = 0.0001) (sensitivity: 90.9%; specificity: 86.7%). Our results suggest reconsideration of classification of meningiomas as atypical based only on minor atypical criteria. The presence of brain invasion and the co-occurrence of sheeting and high mitotic count may be useful to identify high risk cases, which may benefit from adjuvant treatments
Intradural chordoma of the Meckel's cave: a challenging differential diagnosis
No full textChordomas are midline tumors that arise from embryonic remnants of the notochord and are considered to be malignant tumors because of their tendency to invade and destroy the involved bone. Cases of intradural chordomas without bone involvement have been rarely described with a predilection for prepontine location. The absence of bony invasion renders the complete excision of these tumors more feasible and is related to their better prognosis in comparison to conventional chordomas. Herein we report the first intradural chordoma arising in the Meckel's cave. The intradural location of the lesion, outside midline structures, in the absence of bone infiltration, made the differential diagnosis versus other meningeal lesions such as chordoid meningioma challenging. The intense and strong immunohistochemical expression of pan-cytokeratins, S100, cytokeratin-19 and of the notochordal marker brachyury allowed differential diagnosis toward other tumors showing chordoid morphology. The expression of brachyury, which had not been previously analyzed in intradural chordoma, definitely links the histogenesis of this neoplasia to the notochord, similar to that of conventional chordoma. We also show that, different from conventional chordoma, intradural chordoma does not express the metallo-proteinases (MMPs) -2 and -9, which may account for its indolent biological behavior
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Meningeal tumors histologically mimicking meningioma
No full textA number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma. In the present paper, we review meningeal non-meningothelial tumors which may also mimic different histotypes of meningioma at the histological examination. Awareness that these lesions exist may facilitate their recognition and correct diagnosis, which is of fundamental importance for prognosis and an appropriate therapeutic approach. Histological and immunohistochemical clues for the differential diagnosis are discussed. (C) 2012 Elsevier GmbH. All rights reserved
Importance of intraoperative cytology in the definition of cystic solitary brain lesions
No full textno abstract availabl
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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