Stomach, Forestomach - Ectopic Tissue

Stomach, Forestomach - Ectopic pancreas in a female B6C3F1 mouse from a chronic study. Ectopic pancreatic acinar cells are present in the submucosa of the forestomach (arrow).
Figure 1 of 5

Stomach, Forestomach - Ectopic pancreas in a female B6C3F1 mouse from a chronic study (higher magnification of Figure 1). Ectopic pancreatic acinar cells are present in the submucosa of the forestomach.
Figure 2 of 5

Stomach, Forestomach - Ectopic liver in a female F344/N rat from a chronic study. Ectopic hepatocytes (arrows) are present in the submucosa adjacent to the limiting ridge.
Figure 3 of 5

Stomach, Forestomach - Ectopic liver in a female F344/N rat from a chronic study (higher magnification of Figure 3). Ectopic hepatocytes are present in the submucosa adjacent to the limiting ridge.
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comment:
Ectopic tissue can be present in the lamina propria (primarily), submucosa, or subserosa ofthe forestomach. Ectopic tissue can be of any type, but pancreas ( Figure 1





hyperplasia of the overlying squamous epithelium. With ectopic intestine, the presence of gutassociated
lymphoid tissue should not be mistaken for inflammation. Ectopic tissue is considered an
incidental finding.
recommendation:
Whenever present, ectopic tissue should be diagnosed but not graded. The diagnosis should be modified with the tissue of origin.references:
Bertram TA, Markovits JE, Juliana MM. 1996. Non-proliferative lesions of the alimentary canal in rats GI-1. In Guides for Toxicologic Pathology. STP/ARP/AFIP, Washington, DC, 1-16. Full Text: https://www.toxpath.org/docs/SSNDC/GINonproliferativeRat.pdf
Frantz JD, Betton GR, Cartwright ME, Crissman JW, Macklin AW, Maronpot RR. 1991. Proliferative lesions of the non-glandular and glandular stomach in rats. GI-3. In Guides for Toxicologic Pathology. STP/ARP/AFIP, Washington, DC, 1-20. Full Text: https://www.toxpath.org/docs/SSNDC/StomachProliferativeRat.pdf
Web page last updated on: November 24, 2014