Tumor-vessel contact

The adhesion of these cells to the tumor vessel wall occurs when the force between the adhesion molecules on the surfaces of endothelium and effector cell is greater than the hydrodynamic force exerted by blood flow. The deformability of these cells also plays an important role in this process, since it can alter the surface area of contact (Sasaki et al., 1989 Melder and Jain, 1992). Measurement of forces exerted by various adhesion molecules as well as cell deformability in vitro and in vivo is an active area of research in many laboratories, including our own (Ohkubo et al., 1991 Munn et al., 1994). 

Even though sometimes malignant cells arrested in the microcirculation do not migrate further into the organ parenchyma, and grow locally in an expansive fashion until they rupture the vessel wall (Kawaguchi et al., 1983 Crissman et al., 1985 Lapis et al., 1988), in most eases the contact between tumor cells and the endothelium results in EC retraction, with exposure of the underlying BM, followed by invasion of tumor cells in the tissue. Electron microscopy observation on the formation of pulmonary metastasis has shown in-... 

Fig. 10.12. Pelvic sidewall invasion. Transaxial CT at the level of the iliac bifurcation. A mixed solid and cystic adnexal tumor, which was nondifferen-tiated ovarian cancer at histopathology, is located in the pelvis. The left pelvic sidewall, including iliac vessels and psoas muscle, are clearly separated by fat. The right pelvic sidewall (arrow) is in direct contact with the solid tumor component. Furthermore, external and internal iliac arteries are displaced, the latter is encased by tumor (arrowhead)...

Fig. 30.4. Adenocarcinoma in the pancreatic head shows minimal contact to the SMV (grade 1, less than 90° of the vessel circumference). During surgery, no vessel infiltration was found and the tumor could be resected...

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