Ultrastructural study of the vascular response in small early gastric cancer

The microvasculature of the stroma of four cases of small early gastric cancer (EGC) was investigated by conventional electron microscopy. Severe damage to small and large fenestrated capillaries was observed around endothelium-adherent, partially degranulated neutrophils. The findings suggest the existence of neutrophil-mediated injury of endothelial cells during the development of inflammatory responses in small EGC. The severely injured microvessels exhibited increase in vasopermeability, microhaemorrhage, and platelet aggregates. Other microvascular changes included endothelial cell and pericyte activation as well as basal lamina replications, indicative of repeated episodes of endothelial injury, necrosis and regeneration. This new capillary growth within the old basal laminas shared morphological features with a peculiar angiogenic process described in man and animals.