Alimentary System

Stomach, Forestomach - Ulcer

Narrative
Comment:
An ulcer (Figure 1, Figure 2, Figure 3, Figure 4, and Figure 5) is defined as the loss of all epithelial cell layers extending through to the submucosa, whereas an erosion is the loss of superficial epithelial layers of the mucosa. Inflammation at the base of an ulcer and in adjacent tissue and hyperplasia of the adjacent epithelium are very common associated findings. Forestomach ulceration is a common background finding. The forestomach is the most common location for ulcers, but they may occur throughout the gastrointestinal tract. Ulceration of the forestomach can be caused by gavage accidents, or they may be treatment related (especially when the test article is an irritant). However, in many cases the exact cause of ulcers is not known.
Recommendations:
Ulcers of the forestomach should be diagnosed whenever present. They should be graded based on the extent, number, and depth of the lesions. Secondary lesions, such as edema, inflammation, and hyperplasia of the adjacent epithelium, are not diagnosed separately unless they are prominent components of the lesion or they are considered a primary lesion (e.g., the hyperplasia occurred prior to the ulcer). Necrosis of the epithelium is diagnosed instead of ulcer if the necrotic epithelium is still present and attached to the underlying lamina propria (see Stomach, Forestomach - Necrosis ).
Related Links:
Stomach, Forestomach - Necrosis
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

Betton GR. 1998. The digestive system I: The gastrointestinal tract and exocrine pancreas. In: Target Organ Pathology (Turton J, Hooson J, eds). Taylor and Francis, London, 29-60.

Abstract: http://www.amazon.com/Target-Organ-Pathology-Basic-Text/dp/0748401571

Brown HR, Hardisty JF. 1990. Oral cavity, esophagus and stomach. In: Pathology of the Fischer Rat (Boorman GA, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, CA, 9-30.

Abstract: https://www.ncbi.nlm.nih.gov/nlmcatalog/9002563

Leininger JR, Jokinen MP, Dangler CA, Whiteley LO. 1999. Oral cavity, esophagus, and stomach. In: Pathology of the Mouse (Maronpot RR, ed). Cache River Press, St Louis, MO, 29-48.

Abstract: http://www.cacheriverpress.com/books/pathmouse.htm

Puurunen J, Huttunen P, Hirvonen H. 1980. Is ethanol-induced damage of the gastric mucosa a hyperosmotic effect? Comparative studies on the effects of ethanol, some other hyperosmotic solutions, and acetyl-salicylic acid on rat gastric mucosa. Acta Pharmacol Toxicol (Copenh) 47:321-327.

Abstract: http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0773.1980.tb01567.x/abstract
  • Image of ulcer in the forestomach from a male F344/N rat in a chronic study

    Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study. A portion of the epithelium is absent, exposing the underlying submucosa.

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<p>Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study. A portion of the epithelium is absent, exposing the underlying submucosa.</p>

Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study. A portion of the epithelium is absent, exposing the underlying submucosa.
<p>Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study (higher magnification of Figure 1). There is some inflammation associated with the ulcer.</p>

Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study (higher magnification of Figure 1). There is some inflammation associated with the ulcer.
<p>Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study. A large portion of the epithelium is absent, exposing the underlying submucosa.</p>

Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study. A large portion of the epithelium is absent, exposing the underlying submucosa.
<p>Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study (higher magnification of Figure 3). A significant amount inflammation is associated with the ulcer, as well as hyperplasia of the adjacent epithelium.</p>

Stomach, Forestomach - Ulcer in a male F344/N rat from a chronic study (higher magnification of Figure 3). A significant amount inflammation is associated with the ulcer, as well as hyperplasia of the adjacent epithelium.
<p>Stomach, Forestomach - Ulcer in a male B6C3F1 mouse from a subchronic study. A large portion of the epithelium is absent, exposing the underlying submucosa.</p>

Stomach, Forestomach - Ulcer in a male B6C3F1 mouse from a subchronic study. A large portion of the epithelium is absent, exposing the underlying submucosa.

Authors:

Linda H. Kooistra, DVM, PhD, DACVP
Pathologist
Charles River Laboratories, Inc.
Research Triangle Park, NC

Abraham Nyska, DVM, Diplomate ECVP, Fellow IATP
Expert in Toxicologic Pathology
Visiting Full Professor of Pathology
Sackler School of Medicine, Tel Aviv University Timrat Israel

Reviewers:

Joel R. Leininger, DVM, PhD
Senior Pathologist
MedImmune
Washington, DC

Amy Brix, DVM, PhD, DACVP
Senior Pathologist
Experimental Pathology Laboratories, Inc.
Research Triangle Park, NC