Stomach, Forestomach - Cyst

Image of cyst in the forestomach from a male B6C3F1 mouse in a chronic study
Stomach, Forestomach - Cyst in a male B6C3F1 mouse from a chronic study. A keratin-filled cyst is present in the submucosa of the forestomach.
Figure 1 of 3
Image of cyst in the forestomach from a female F344/N rat in a chronic study
Stomach, Forestomach - Cyst in a female F344/N rat from a chronic study. A keratin-filled cyst is present in the submucosa at the junction of the forestomach and glandular stomach.
Figure 2 of 3
Image of cyst in the forestomach from a female F344/N rat in a chronic study
Stomach, Forestomach - Cyst in a female F344/N rat from a chronic study (higher magnification of Figure 2). The wall of the cyst exhibits normal cellular maturation.
Figure 3 of 3
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comment:

Cysts (including keratin cysts and epithelial inclusion cysts) can occur in the esophagus or forestomach near the limiting ridge and antral mucosa. Cysts in the nonglandular stomach are usually lined by keratinized stratified squamous epithelium and less frequently by mucous cells. Usually cysts are considered incidental findings.

recommendation:

Cysts should be diagnosed and described in the pathology narrative. Cysts are not graded in NTP studies unless the pathologist feels the cysts are treatment related and severity grading would reveal a treatment effect.

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

Chan PC, Mahler J, Peddada S, Lomnitski L, Nyska A. 2003. Forestomach tumor induction by 2,4-hexadienal in F344N rats and B6C3F1 mice. Arch Toxicol 77:511-520.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/12879212

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

National Toxicology Program. 1993. NTP TOX-29. Toxicity Studies of Cupric Sulfate (CAS No. 7758-99-8) Administered in Drinking Water and Feed to F344/N Rats and B6C3F1 Mice. NTP, Research Triangle Park, NC.
Abstract: http://ntp.niehs.nih.gov/go/13830