Reproductive System, Female

Vagina - Mucification

Narrative
Comment:

In general, vaginal mucification (Figure 1 and Figure 2) is induced by progesterone excess. Therefore, it occurs normally during proestrus, pregnancy, and pseudopregnancy. It is also seen with hyperprolactinemia, such as that caused by a prolactin-secreting pituitary neoplasm. It is characterized histologically by changes in the superficial epithelial cells of the vaginal mucosa, which become cuboidal or cylindrical with prominent vacuolation. The vacuolated cells contain PAS- and/or Alcian blue-positive material (mucin). In some cases, the mucification of the vagina may be a treatment effect. The degree of vacuolation, the thickness of the epithelium, and the lack of a band of keratinization between the epithelium and the mucified layer are indicative that the mucification is not part of a normal cyclical change.

Recommendations:

Vagina - Mucification should be diagnosed and graded when it is not considered a component of normal estrous cyclicity, pregnancy, or pseudopregnancy, or if it is considered excessive in the opinion of the pathologist.

References:

Greaves P, Faccini JM. 1984. Female genital tract. In: Rat Histopathology: A Glossary for Use in Toxicity and Carcinogenicity Studies. Elsevier, Amsterdam, 171-179.

National Toxicology Program. 2006. NTP TR-525. Toxicology and Carcinogenesis Studies of 2,3,4,7,8-Pentachlorodibenzofuran (PeCDF) (CAS No. 57117-31-4) in Female Harlan Sprague-Dawley Rats (Gavage Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/tr525abs

Westwood FR. 2008. The female rat reproductive cycle: A practical histological guide to staging. Toxicol Pathol 36:375-384.

Abstract: https://www.ncbi.nlm.nih.gov/pubmed/18441260

Yuan YD. 1991. Female reproductive system. In: Handbook of Toxicologic Pathology (Haschek WM, Rousseaux CG, eds). Academic Press, San Diego, CA, 891-935.

  • Image of mucification in the vagina from a female Harlan Sprague-Dawley rat in a chronic study

    Vagina - Mucification in a female Harlan Sprague-Dawley rat from a chronic study. The epithelium of the vagina is superficially mucified.

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Vagina - Mucification in a female Harlan Sprague-Dawley rat from a chronic study. The epithelium of the vagina is superficially mucified.
Vagina - Mucification in a female Harlan Sprague-Dawley rat from a chronic study. The epithelium of the vagina is superficially mucified.
Vagina - Mucification in a female Harlan Sprague-Dawley rat from a chronic study (higher magnification of Figure 1). The vagina epithelium is composed of individual epithelial cells distended by a pale mucin-like material.
Vagina - Mucification in a female Harlan Sprague-Dawley rat from a chronic study (higher magnification of Figure 1). The vagina epithelium is composed of individual epithelial cells distended by a pale mucin-like material.

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