Article
Immunohistochemical findings and evaluation of mast cell infiltration in secretory meningioma
Immunohistochemie und Auswertung von Mastzell-Infiltration bei sekretorischen Meningeomen
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Published: | May 4, 2005 |
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Outline
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Objective
Secretory meningiomas constitute a relatively rare subtype of meningiomas. This study aimed to obtain more information about the immunohistochemical characteristics of this histological entity and to analyse the effects of histological factors such as the presence of mast cells on the radiological evidence of surrounding tumour edema which frequently occurred in this subtype of meningioma.
Methods
Fourteen cases of secretory meningiomas were examined. Relevant clinical information was obtained from the patient files. The peritumoural edema was determined either by CT or MRI scans and graded as small, moderate and severe. In order to perform the quantitative evaluation of mast cells in secretory meningiomas in a comparison with other meningiomas, fourteen non-secretory meningiomas were randomly selected and used as control group. The surgical specimens were processed using the routine staining and immunohistochemistry.
Results
The immunohistochemical staining of carcinoembryonic antigen was positive within the secretory droplets and the cells surrounding them in all cases. Ki 67 (MIB 1) proliferative index mean values were 2.4%, indicating a low expression in all secretory meningiomas. Moreover, from our statistical analysis there is no clear-cut pattern of various types of cytokeratins emerging in secretory meningiomas. The secretory meningiomas were characterised by a significantly increased amount of mast cells, as compared to non-secretory meningiomas of different grades.
Conclusions
Secretory meningiomas are often associated with severe peritumoral edema causing signs and symptoms of increased intracranial pressure. So far, the initial step inducing peritumoral edema cannot be demonstrated. Many histological findings such as increased numbers of mast cells as found in our study, and pericytic proliferation might be involved in the pathophysiological process of this vasogenic brain edema. Demonstration of mediators in the tumour tissue might define the role of mast cells and provide more information about the nature of this particular type of meningiomas.