Microvascular changes in human gastric carcinomas with coagulative necrosis: an ultrastructural study.

Ultrastructural findings in three cases of gastric carcinoma with coagulative necrosis are reviewed with special emphasis on microvascular changes. Intratumoral microvasculature revealed more or less stabilized vessels. Some were characterized by a close association between pericytes and endothelial cells, whereas others showed laminated basement membrane, with a loose association between pericytes and endothelial cells. Some mural cells exhibited ultrastructural signs of regressive changes, including lipofuscin granules, swollen mitochondria, and cytoplasmic lucency. These findings are discussed in relationship to a number of recent studies of the microvascular injury caused by hypoxia and reoxygenation, in humans and animals.