Elektronenmikroskopie der Hämangioblastome des ZNS und der angioblastischen Meningiome

Summary

4 hemangioblastomas of the cerebellum, 1 of the choroid plexus, 1 of the spinal cord, and 3 angioblastic meningiomas of the brain were investigated with the electron microscope. They all show a similar histological arrangement of vessels, intervascular cells (Zwischenzellen), and the intercellular space. The vessels of the tumors regardless where they originate from are identical in their appearance. They differ from autochthonous vessels by the irregular form of the endothelium and the presence of pores. The “Zwischenzellen” of hemangioblastomas are not so uniform as those of angioblastic meningiomas. Corresponding to differences in the nucleus/cytoplasma ratio, the development of the ER and the number of cytofilaments as well as the content of lipid droplets hemangioblastomas can be subdivided in 4 types. Nevertheless they constitute a cytological unity. In 3 hemangioblastomas mast cells were found. glial cells mixed up with tumor cells are present only in the border of tumorous and nervous tissue. The extracellular space is filled either with a protein-rich exsudate or with collagen fibrils. — The electron microscopic findings support the histological identity of hemangioblastomas and angioblastic meningiomas. The relation of “Zwischenzellen” to the vessel walls, their similarity to endothelial cells, and their tendence to form basement membranes indicate that they derive from blastomatous vessels.