[Experimental studies on tumor vascularization (author's transl)].

: The development of tumor vascularization of subcutaneously and intramuscularly implanted myelosarcoma I 58 of the rat was investigated. Various stages of tumor development were studied by arteriography, venography and microangiography. The roentgenographic signs known intravital angiography are related to the temporal sequence of the tumor development. The most significant signs during the period of observation are increase of number, dilatation and winding of arteries and veins in the tumor area. These alterations are observed earlier and more pronounced at the veins. Following subcutaneous tumor implantation, in all developmental stages there is a concentric arrangement of the tumor vessels with a dense peripheral tumor vascularization around an avascular tumor center. Contrary to this, following intramuscular tumor implantation, diffuse penetration of the tumor with vessels is observed. A peripheral vascularization type occurs with necrosis which is combined by an avascular tumor center. Already in the medium stage of tumor development signs of arterio-venous shunts occur regularly. Central tumor necrosis leads to extravasation of contrast medium which is known as a late tumor sign. The vascular pattern of the myelosarcoma T 58 is not only determined by the temporal sequence but also by the location of the tumor.