Reproductive System, Female

Uterus - Adenomyosis

Narrative

Comment:

Adenomyosis (Figure 1, Figure 2, Figure 3, and Figure 4) is the presence of normal or hyperplastic endometrial glands and stroma that extend into the myometrium. Occasionally epithelial cells can extend onto the serosal surface of the uterus. Hormonal imbalance is a key factor. It is more common in some strains of mice (B6C3F1) than in rats and is more common in aged mice. It is important to differentiate adenomyosis from neoplasms. Adenomyosis has no atypia of the epithelial cells, which is a useful distinguishing feature. Adenomyosis may be differentiated from adenocarcinoma by examining the epithelial cells and by the presence of normal uterine stroma. Malignant epithelial cells of adenocarcinomas exhibit cellular pleomorphism and often are multilayered. Adenomyosis should not be described as endometriosis, which is diagnosed only in primates (in endometriosis, the glands spread to the peritoneal cavity).

Recommendations:

Uterus - Adenomyosis should be diagnosed and graded whenever present.

References:

Davis BJ, Dixon D, Herbert RA. 1999. Ovary, oviduct, uterus, cervix and vagina. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, Boorman GA, Gaul BW, eds). Cache River Press, Vienna, IL, 409-444.

Greaves P. 2012. Female genital tract. In: Histopathology of Preclinical Toxicity Studies: Interpretation and Relevance in Drug Safety Evaluation, 4th ed. Elsevier, Amsterdam, 667-724.

Leininger JR, Jokinen MP. 1990. Oviduct, uterus and vagina. In: Pathology of the Fischer Rat (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, CA, 443-459.

Maekawa A, Maita K. 1996. Susceptibility of the female genital system to toxic substances. In: Pathobiology of the Aging Mouse (Mohr U, Dungworth DL, Capen CC, Carlton WW, Sundberg JP, Ward JM, eds). ILSI Press, Washington, DC, 481-493.

National Toxicology Program. 2000. NTP TR-484. Toxicology and Carcinogenesis Studies 2-Butoxyethanol (CAS No. 111-76-2) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/9770

National Toxicology Program. 2001. NTP TR-501. Toxicology and Carcinogenesis Studies of p,p'-Dichlorodiphenyl Sulfone (CAS No. 80-07-9) in F344/N Rats and B6C3F1 Mice (Feed Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/14880

All Images

Uterus - Adenomyosis in a female Harlan Sprague-Dawley rat from a chronic study. Glands are adjacent to the serosal surface of the myometrium (arrows).

Uterus - Adenomyosis in a female Harlan Sprague-Dawley rat from a chronic study (higher magnification of Figure 1). There are well-differentiated glands within the myometrium.

Uterus - Adenomyosis in a female Harlan Sprague-Dawley rat from a chronic study. Endometrial glands and stroma are evident within the myometrium.

Uterus - Adenomyosis in a female Harlan Sprague-Dawley rat from a chronic study. There are well-differentiated glands within the myometrium.

Authors and Reviewers

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