THE FINE STRUCTURAL STUDY ON BLOOD VESSELS WITHIN HUMAN BRAIN TUMORS

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The blood vessels of human brain tumors were studied in comparison with normal architecture under electron microscope. 1) In benign glial tumors, their blood vessels were apperently similar to those of normal tissue. 2) In malignant glial tumors, immature vessels were observed as might be expected in young, immature cells. The nucleus-cytoplasm ratio was high, and cytoplasm was filled with an abundance of organelles, especially free ribosomes and mitochondria. These findings suggest a high metabolic activity of endothelium. Opened intercellular junction, increased pinocytotic and coated vesicles were recognized in the endothelial cells, and proliferated endothelial cells had irregular luminal surface and elongated processes. These facts suggest an increased capacity to trasfer materials between the luman and the parenchyma. 3) In non-glial tumors, a fenestrated endothelium was commonly observed. The perivascular basement membrane was often reduplicated and was composed of several layers. 4) Adhesive devices between adjacent endothelial cells presented commonly macula adherens and desmosome-like pattern. 5) Tubular bodies were observed in the vascular endothelial cytoplasm of glioblastoma multiforme, pinealoma, craniopharyngioma, astrocytoma, teratoma with choriocarcinoma and pituitary adenoma. These tubular bodies showed various spectra from immature type to mature, might reflect a marked vascular reaction in angiogenesis with brain tumor formation. 6) Furthermore, in the case of pinealoma, its vascular basement membrane filled with collagen fibers and some dense materials merged continuously into the intercellular space of tumor tissue as seen in meningioma. These facts suggest that the origin of the pinealoma might be the mesodermal tissue.