Oral Mucosa - Cyst, Squamous

Oral mucosa - Cyst, Squamous in a female F344/N rat from a chronic study. There is a keratin-filled squamous cyst (arrow) beneath the mucosa in the hard palate.
Figure 1 of 3

Oral mucosa - Cyst, Squamous in a female F344/N rat from a chronic study (higher magnification of Figure 1). There is a keratin-filled squamous cyst (arrow) beneath the mucosa in the hard palate.
Figure 2 of 3
comment:
Squamous cysts ( Figure 1


recommendation:
Squamous cysts are considered incidental background lesions but should be diagnosed when present for completeness sake. Cysts are generally not graded in NTP studies.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
National Toxicology Program. 2010. NTP TR-558. Toxicology and Carcinogenesis Studies of 3,3’,4,4’-Tetrachloroazobenzene (TCAB) (CAS No. 14047-09-7) in Harlan Sprague Dawley Rats and B6C3F1 Mice (Gavage Studies). NTP, Research Triangle Park, NC. Abstract: http://ntp.niehs.nih.gov/go/33564
Web page last updated on: November 24, 2014