Reproductive System, Female

Ovary, Paraovarian Tissue - Cyst

Narrative
Comment:

Paraovarian cysts likely arise from vestigial remnants of the mesonephric and paramesonephric ducts. Paraovarian cysts are not connected to the ovary; they are adjacent to the ovary in the mesovarium or mesosalpinx (Figure 1, Figure 2, Figure 3 and Figure 4). Paraovarian cysts are lined by flattened, cuboidal or columnar epithelium, and the epithelium may be ciliated. A connection to paraovarian structures in the mesovarium may be seen. The presence of smooth muscle in the wall of the cyst is variable.

Recommendations:

Paraovarian cysts should be diagnosed, but cysts occurring as background lesions need not be graded. In the case of paraovarian cysts, the diagnosis should include the type of cyst/location as a modifier (i.e., Ovary, Paraovarian tissue - Cyst). If the cysts are thought to be treatment related, they may be graded to fully characterize the treatment effect. If applicable, the terms "bilateral" and "multiple" may be included in the diagnosis.

References:

Alison RH, Morgan KT, Montgomery CA. 1990. Ovary. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, CA, 429-442.

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.

Long GG. 2002. Apparent mesonephric duct (rete anlage) origin for cysts and proliferative epithelial lesions in the mouse ovary. Toxicol Pathol 30:592-598.

Abstract: https://www.ncbi.nlm.nih.gov/pubmed/12371668

Montgomery CA, Alison RH. 1987. Non-neoplastic lesions of the ovary in Fischer 344 rats and B6C3F1 mice. Environ Health Perspect 73:53-75.

Abstract: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1474552/

National Toxicology Program. 1982. NTP TR-228. Carcinogenesis Bioassay of Vinylidene Chloride (CAS No. 75-35-4) in F344 Rats and B6C3F1 Mice (Gavage Study). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/7064

National Toxicology Program. 1983. NTP TR-244. Toxicology and Carcinogenesis Studies of a Polybrominated Biphenyl Mixture (Firemaster FF-1) in F344/N Rats and B6C3F1 Mice (Gavage Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/7095

National Toxicology Program. 1993. NTP TR-398. Toxicology and Carcinogenesis Studies of Polybrominated Biphenyls (CAS No. 67774-32-7) (Firemaster FF-1®) in F344/N Rats and B6C3F1 Mice (Feed Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/12247

Peluso JJ. 1992. Morphologic and physiologic features of the ovary. In: Pathobiology of the Aging Rat (Mohr U, Dungworth DL, Capen CC, eds). ILSI Press, Washington, DC, 337-349.

  • Image of cyst (paraovarian tissue) in the ovary from a female F344/N rat in a subchronic study

    Ovary, Paraovarian tissue - Cyst in a female F344/N rat from a subchronic study (higher magnification of Figure 1). The cyst is lined by cuboidal to columnar epithelium and surrounded by smooth muscle.

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Ovary, Paraovarian tissue - Cyst in a female F344/N rat from a subchronic study. There is a large fluid-filled space in the mesovarium.
Ovary, Paraovarian tissue - Cyst in a female F344/N rat from a subchronic study. There is a large fluid-filled space in the mesovarium.
Ovary, Paraovarian tissue - Cyst in a female F344/N rat from a subchronic study (higher magnification of Figure 1). The cyst is lined by cuboidal to columnar epithelium and surrounded by smooth muscle.
Ovary, Paraovarian tissue - Cyst in a female F344/N rat from a subchronic study (higher magnification of Figure 1). The cyst is lined by cuboidal to columnar epithelium and surrounded by smooth muscle.
Ovary, Paraovarian tissue - Cyst in a female B6C3F1/N mouse from a subchronic study. Multiple large, fluid-filled spaces are located in the rete ovarii.
Ovary, Paraovarian tissue - Cyst in a female B6C3F1/N mouse from a subchronic study. Multiple large, fluid-filled spaces are located in the rete ovarii.
Ovary, Paraovarian tissue - Cyst in a female B6C3F1/N mouse from a subchronic study (higher magnification of Figure 3). A large-fluid filled cyst is present in the mesovarium.
Ovary, Paraovarian tissue - Cyst in a female B6C3F1/N mouse from a subchronic study (higher magnification of Figure 3). A large-fluid filled cyst is present in the mesovarium.

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