Meningiomas: histogenesis and classification. A comparative morphological study.

80 meningiomas were analyzed with various morphological methods including smear preparations, frozen section conventional histology. In all, the establishment of short term in-vitro growth was attempted and led to rapid cell proliferation in all but few exceptions. Electron microscopy was equally performed in the cases. In 37 of these meningiomas, commercially available antibodies against a whole pattern of tissue markers including cytokeratin, fibronectin, vimentin, S-100 protein and others were applied and visualized with the PAP method. The same was done with 4 in-vitro grown meningiomas. The sample of tumors comprised the major subtypes; age and sex distribution were consistent with known data. Electron microscopy showed only quantitative differences between different types, exhibiting as main features folded membranes with desmosomes and intermediate filaments. Cell types occurring in-vitro were dependent on the stage of proliferation. The tissue marker distribution showed vimentin as common to almost all meningiomas and fibronectin to half of them. Both antigens were observed after short term in-vitro growth in the tumor cells. It is concluded, that the central group of meningiomas despite of many different particular features has a common and uniform cellular make up demonstrated in all methods reported. The bearing of the intermediate mesodermal(neuro) ectodermal position of those tumors for their proper classification at the time being can only be discussed.