[An immunohistochemical and ultrastructural study on 76 cases of meningioma].

Seventy-six cases of meningioma of various light microscopic features were studied immunohistochemically by using 6 kinds of antibodies directly against epithelial, mesenchymal and neural components. Except for hemangiopericyte meningiomas which only showed vimentin positive, expressions of vimentin and EMA were obtained in almost all the meningiomas. Thirteen meningiomas were investigated by electron microscopy. The electron micrograph of meningiomatous cell showed presence of interdigitation of the adjacent cell membrane with desmosome and variable amounts of intermediate filaments in cytoplasm, although the re were different varieties of cell types. 2 hemangiopericyte meningiomas showed presence of different ultrastructures, which contained many pericytes and cells with a large number of RER. These results provide evidences of the fact that meningioma possessed the features of both mesenchymal and epithelial tissue. In regard to histogenesis, findings reported suggest that meningioma most probably arise from the arachnoid cap cells. Additionally, some distinct subtypes of meningioma are reported, including secretory meningioma, microcystic meningioma and oncocytic meningioma.