Reproductive System, Female

Vagina - Cyst

Narrative
Comment:

Cysts are rarely found in the walls of rat vaginas (Figure 1, Figure 2 and Figure 3). These are usually lined by stratified squamous epithelium and filled with keratin and cellular material, which may have inflammatory debris. These cysts are dilated, fluid-filled structures with an epithelial lining. They may have a smooth muscle wall (mesonephric duct remnant) and also may have squamous metaplasia and/or keratinization. Cysts must not be confused with abscesses, which are predominantly filled with neutrophils in various stages of degradation and do not have an epithelial lining.

Recommendations:
Vagina - Cyst should be diagnosed but need not be graded. If the cysts appear to be treatment related, they may be graded at the pathologist’s discretion if grading would help characterize the treatment effect. Associated inflammatory changes should not be diagnosed separately unless warranted by severity.
References:

National Toxicology Program. 1994. NTP TR-442. Toxicology and Carcinogenesis Studies of p-Nitrobenzoic Acid (CAS No. 62-23-7) in F344/N Rats and B6C3F1 Mice (Feed Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/6028
  • Image of cyst in the vagina from a female F344/N rat in a chronic study

    Vagina - Cyst in a female F344/N rat from a chronic study. A prominent thin-walled cyst is present in the vaginal wall.

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Vagina - Cyst in a female F344/N rat from a chronic study. A prominent thin-walled cyst is present in the vaginal wall.
Vagina - Cyst in a female F344/N rat from a chronic study. A prominent thin-walled cyst is present in the vaginal wall.
Vagina - Cyst in a female F344/N rat from a chronic study (higher magnification of Figure 1). Cuboidal epithelium lines the cyst, which contains amorphous eosinophilic debris.
Vagina - Cyst in a female F344/N rat from a chronic study (higher magnification of Figure 1). Cuboidal epithelium lines the cyst, which contains amorphous eosinophilic debris.
Vagina - Cyst in a female F344/N rat from a chronic study. A thin-walled cyst containing eosinophilic debris is present in the wall of the vagina.
Vagina - Cyst in a female F344/N rat from a chronic study. A thin-walled cyst containing eosinophilic debris is present in the wall of the vagina.

Authors

Gabrielle Willson, BVMS, Dip RC Path, FRC Path, MRCVS
Senior Pathologist
Experimental Pathology Laboratories, Inc.
Research Triangle Park, NC

Karen Y. Cimon, DVM, MS
Senior Pathologist
Experimental Pathology Laboratories, Inc.
Research Triangle Park, NC

Reviewers

Karen S. Regan, DVM, DABT, DACVP
Pathologist
Regan Path/Tox Services, Inc.
Ashland, OH  

Darlene Dixon, DVM, PhD, DACVP, Fellow, IATP
Group Leader, Molecular Pathogenesis Group
National Toxicology Program Laboratory
National Toxicology Program
National Institute of Environmental Health Sciences, Research Triangle Park, NC