Microvascular architecture of human epicolic and paracolic lymph nodes located in the vicinity of colon cancer: A SEM study of corrosion casts

The vascular systems of epicolic and paracolic lymph nodes located in the vicinity of colon tumors resected from three patients were investigated by corrosion casting and scanning electron microscopy. Large vessels entered the nodes either at one site, not always corresponding with the anatomical hilus, or at 2–4 sites located along their perimeters. In the cortical zone of most examined nodes, the location of lymphoid nodules was marked by rosette-like capillary arrays drained by peripheral arcuate venules. The paracortex and medulla showed a dense capillary network with areas of tortuous capillaries, sometimes forming glomerular arrays suggesting nonsprouting angiogenesis by capillary elongation. Venules were abundant, especially in the paracortex and medulla, but high endothelial venules showing characteristic imprints of bulging endothelial cells in the casts were very rarely observed. Focal angiogenesis, abundance of venules and scarcity of high endothelial venules could result from remodeling of blood vessels induced by the tumor.