Stomach, Glandular Stomach - Ectopic Tissue

Ectopic pancreas (Figure 1 and Figure 2), liver (Figure 3 and Figure 4) or intestines (Figure 5 and Figure 6) occur rarely in the submucosa of the glandular stomach. Hepatocytes in the submucosa/lamina propria of the glandular stomach have been reported as a rare occurrence in the B6C3F1 mouse, as well as other mouse strains. Mice from control and treatment groups and both sexes have been found with gastric hepatocytes. This condition may arise from metaplasia of a primary stomach cell type but more likely is the result of a developmental defect and is considered an incidental finding. Invasion or metastasis from a liver neoplasm must be ruled out in all cases, even if the cells do not appear neoplastic. Ectopic pancreatic tissue, composed of acinar and ductal cells, has also been described in the submucosa of the mouse stomach. Foci of intestinal tissue can occur in the glandular stomach (Figure 5 and Figure 6). This is considered an incidental congenital lesion similar to hepatic/pancreatic ectopic foci in the stomach. It is differentiated from intestinal metaplasia by occurrence outside of the mucosal epithelium and a lack of association with other changes in the epithelium, such as hyperplasia, atypical changes (dysplasia), or gastric carcinoma.