Pathology
Adenocarcinomas of the stomach derive from mucous cells, not from parietal or chief cells. Subtypes have been described related to differentiation and characteristics of growth and spread: the intestinal type (resembling colonic carcinoma) has a better prognosis that the diffuse type; the expanding type (cells maintaining a close relationship) has a better prognosis than the infiltrative type. The tumors are most frequently found in the distal third of the stomach and may be exophytic (with or without a stalk), diffusely infiltrative throughout the stomach (sometimes termed linitis plastica), or ulcerated.