[Ultrastructure of capillary permeability in human brain tumors--4: Cerebral edema associated with meningiomas].

The cerebral edema, as judged by computed tomographic scan, associated with supratentorial meningiomas was assessed in 43 cases. No relationship to the occurrence or the degree of edema could be established with respect to meningioma location and histological type. The larger the meningioma, the more likely the presence of and the severity of cerebral edema. The materials were obtained from surgically removed specimens in 6 cases of meningiomas with and without associated cerebral edema, and tumor vessels were studied with conventional ultrathin section and freeze-fracture replica techniques. The characteristic findings of these tumor vessels were thinning of endothelium and many fenestrations, short and in fact open tight junctions. Tight junctions between endothelial cells were composed of one or two strands which appeared to be a discontinuous array of particles. The ultrastructural appearance of tumor vessels is similar to that seen in meningiomas with and without associated cerebral edema.