脳腫瘍血管透過性の超微形態—脳原発性悪性黒色腫の腫瘍血管

Ultrastructure of Capillary Permeability in Human Brain Tumor: Primary meningeal malignant melanoma

I．はじめに

　脳原発性悪性黒色腫（以下原発性黒色腫）は脳軟膜に存在するmelanocyteを発生母地とするが，比較的稀で，脳腫瘍全国集計調査報告^2）によると，22,898例中16例，0.07％にすぎない．

　原発性黒色腫の腫瘍血管について，他の原発性脳腫瘍と超微形態学的に比較，検討を行った．

The tumor vessels of a primary meningeal malignant melanoma were studied by electron microscopy. There were neumerous endothelial fenestrae and basal lamina abnormalities in the intrinsic tumor capillaries. They re-sembled the tumor vessels found in nonglial tumors, but were distinctly different from those seen in glial tumors with nonfenestrated capillaries. These findings were anticipated because leptomeninges have fene-strated capillaries In phosphorus-31 MR spectroscopy, pH of the subjects with brain tumors showed a statistically signi-ficant elevation compared with that of the volunteers. In the subjects with benign tumors, only the elevation of pH was significant compared with that in volunteers. There was no other difference. This result suggests that benign tumors have an almost normal metabolic mechanism. Malignant brain tumors showed a decrease of PCr and an increase of Pi and PME. The increase of Pi indicates the increase of energy consumption. The increase of PME is connected with the acceleration of cell proliferation. These findings suggest that, in energy metabolism, there is a difference between malignant tumors and benign tumors. Phosphorus-31 spectroscopy has the potential to investigate the metabolism in vivo.