Adenoma, Glandular Stomach, Rat

Adenomas are grossly observed as plaque-like or nodular lesions covered with glandular epithelium with a smooth and glossy or ulcerated surface. They are often seen as white or translucent nodules of various sizes. In some cases, the lesions appear as well-demarcated thickenings of the mucosa accompanied by polypoid structures on the surface, the thickening mainly being due to hyperplasia of foveolar epithelial cells. Adenomas are predominantly localized at the pyloric antrum, but they also occur in the fundic mucosa when treatment with mucosa-damaging agents such as iodoacetamide (Takahashi et al. 1976) is carried out prior to carcinogen treatment.