[Light and electron microscopy in determining the histogenesis of vascular tumors].

Six human vascular neoplasms were studied in light and electron microscopes. Electron microscopic examinations revealed specific ultrastructural features of tumour pericytes, cells of smooth-muscle tumours and tumour endothelium. Some tumours were found to be polymorphic in their cellular composition. The electron microscopy method revealed polymorphism of the tumour with diffuse distribution of cell elements (the presence of endothelial strata in hemangiopericytoma or the presence of the pericytic component in an endothelioma) but proved to be of low effectiveness in focal distribution of cell elements. It is concluded from the foregoing that simultaneous utilization of light and electron microscopy is necessary for vertification of such complicated neoplasms as vascular tumours of man.