Morphological changes in gastric carcinoma with progression.

By combining morphological two indices, namely, (1) the degree of differentiation of glandular tubules (well or poor) and (2) the amount of intracellular mucus (rich or poor), we previously classified histological types of gastric carcinoma into four types. Using this histological classification, we studied the morphological changes of gastric carcinoma according to extra-gastric invasion in 200 autopsy and 200 resected cases. In cases in which the predominant histological type in the lamina propria was "tubular differentiation--well, mucus in cytoplasm--poor," there was a greater incidence of co-existence with other histological types. In many of these cases, the predominant histological findings changed to "tubular differentiation--poor" in the subserosa, followed by direct invasion into neighboring extra-gastric tissues. In all cases in which the predominant histological type in the lamina propria was "tubular differentiation--poor," the predominant histological type in the subserosa was also "tubular differentiation--poor." To understand the mode of extension of gastric carcinoma in relation to the histological type, we must consider not only the characteristics of the predominant histological types of carcinoma but also those of co-existing types, especially in cases of "tubular differentiation--well, mucus in cytoplasm--poor."