[The fine structure of endothelial cells in meningiomas (author's transl)]

The fine structure of the endothelial cells in meningiomas was studied by the electron microscopy. There were an increased number of pinocytotic vesicles and fenestrations especially at the attenuated portion of the endothelial cells. Intraluminal infoldings of the plasma membrane were frequently found. Those were certainly abnormal and all probably related to the increased vascular permeability of the endothelial cells. Usually large number of tubular bodies and associated tubule-containing vacuoles were found. The constituent tubules seemed identical but the various bodies differed in terms of their size, matrix, and the packing of the tubules within them. The significance of those structures is unknown.