Reproductive System, Female

Oviduct - Mesonephric Duct Remnant

Narrative
Comment:

These remnants of the mesonephric duct may be unilateral or bilateral. They are tubular or cystic structures with an epithelial lining and have a layer of smooth muscle (Figure 1 and Figure 2). These must be distinguished from cysts in the region of the ovary, such as bursa cysts. A distended bursa collapses at dissection, disclosing an intact ovary within it. Cysts occurring in the ovary are found within the ovarian parenchyma and can generally be dissected intact. Cysts of the paraovarian tissue are characterized by a large fluid-filled sac in the mesovarium. These cysts are lined by cuboidal to columnar epithelium, surrounded by smooth muscle, and filled with pale-staining eosinophilic flocculent material.

Recommendations:

Oviduct - Mesonephric duct remnant should be diagnosed whenever present but need not be graded.

References:

King NW. 1978. The reproductive tract. In: Pathology of Laboratory Animals (Benirschke K, Garner FM, Jones TC, eds). Springer, New York, 509-580.

National Toxicology Program. 2006. NTP TR-533. Toxicology and Carcinogenesis Studies of Benzophenone (CAS No. 119-61-9) in F344/N Rats and B6C3F1 Mice (Feed Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/20475
  • Image of mesonephric duct remnant in the oviduct from a female B6C3F1 mouse in a chronic study

    Oviduct - Mesonephric duct remnant in a female B6C3F1/N mouse from a chronic study. Multiple cross sections of cystic structures are adjacent to the oviduct.

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Oviduct - Mesonephric duct remnant in a female B6C3F1/N mouse from a chronic study. Multiple cross sections of cystic structures are adjacent to the oviduct.
Oviduct - Mesonephric duct remnant in a female B6C3F1/N mouse from a chronic study. Multiple cross sections of cystic structures are adjacent to the oviduct.
Oviduct - Mesonephric duct remnant in a female B6C3F1/N mouse from a chronic study (higher magnification of Figure 2). The ducts are lined by a single layer of cuboidal epithelium.
Oviduct - Mesonephric duct remnant in a female B6C3F1/N mouse from a chronic study (higher magnification of Figure 2). The ducts are lined by a single layer of cuboidal epithelium.

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