PROLIFERATION OF BLOOD-VESSELS AND STROMA IN BRAIN TUMORS - ENZYME-HISTOCHEMICAL STUDY

Proliferation of the vascular endothelium occurring in [human] brain tumors is accompanied by a proliferation of histiocytes in the peripheral part of the vessel wall. These histiocytes infiltrate the tumor tissue in a regular pattern. Enzyme-histochemically, there are marked differences between the activities of alkaline phosphatase, 5-nucleotidase and ATPase in normal and proliferating blood vessels. The process encompasses reactive changes evoked by the destroyed perivascular sheath of astroglial foot processes and subsequent edema in the tumor and surrounding parenchyma. There are often tumor areas where diminished vascular permeability is established by proliferation of perivascular connective tissue. Here the edema completely disappeared. A clearcut influx of monocytes from the blood into the vessel wall is seen only in the vicinity of necrotic foci. The number of histiocytes is increased and their turnover is observed in swollen macrophages. In the rest of the tumor, influx of monocytes and activity of macrophages are inconspicuous.