histology , positive immunostaining of tumour cells with factor viii antigen , a specific marker of endothelial cells and the ultrastructural demonstration of weibel-palade bodies in endothelial cells of the tumour vessels suggested a malignant mesenchymal tumour of angiosarcoma type presumably arising from the spinal meninges , and broadly invading the spinal cord .
C0225336
endothelial cells
C0018923
angiosarcoma