Signet Ring Cell Carcinoma of the Stomach in N-methyl-N'nitro-N-nitrosoguanidine-Administered Rats. Report of Two Cases with Special Reference to Its Histogenesis

Abstract

Sprague-Dawley rats, orally administered with N-methyl-N'-nitro-N-nitrosoguanidine (100 ,u glml dissolved in drinking water given ad libitum) for 28 weeks were sacrificed 12 weeks after the last administration. Of 89 neoplastic lesions from 96 rats, two rats developed signet ring cell carcinoma (SRC) with focal mixture of poorly differentiated adenocarcinoma in one, involving the full thickness of the gastric wall and blood vessels. Aside from the incipient atypical cell growth along the foveolar epithelium there was a histochemical similarity of mucin between SRC and atypical foveolar epithelial cells. These observations suggest that SRC develops from non-metaplastic foveolar epithelium of the stomach.