Table 2 Mesonephric-derived entities: Benign and malignant lesions

Mesonephric remnants (MRs)

Typically identified in asymptomatic women in reproductive and postmenopausal age groups.

MRs can be seen in up to 22% of adults and 40% of newborns and children.

The lateral wall of the cervix (3 and 9 o’clock) is the most frequent location.

Not associated with increased risk of malignancy.

MRs are non-mass forming and thus are not clinically or grossly apparent.

Clusters or linear arrays of small tubules lined by bland cuboidal epithelia, lacking mucin.

PAX8, GATA3, and CD10 (+); calretinin 10% (+); ER, PR, p16, and p53 (−)

No studies have evaluated molecular alterations.

Mesonephric hyperplasia, endometrial adenocarcinoma with cervical stroma invasion.

Gartner’s duct cyst (mesonephric cyst)

Uncommon (<  1%); typically located in the lateral or anterior wall of the vagina.

May be associated with renal and ureteral abnormalities.

No increased risk of malignancy.

Presentation is similar to other vaginal cysts.

Bland, cuboidal to low columnar non-mucinous epithelia

CD10, GATA3, PAX8, and calretinin (+)

No studies have evaluated molecular alterations.

Müllerian cysts, Bartholin duct cysts (showing mucinous epithelia)

Mesonephric hyperplasia (MH)

Usually an incidental microscopic finding in reproductive and postmenopausal age groups. May be rarely associated with erosion, nodularity, or an abnormal Pap smear.

Usually not apparent on gross examination.

Occasional thickening of the cervical wall.

Formation of a discrete mass is rare.

Similar to mesonephric remnants, the proliferations are larger (>  6 mm) and more numerous, with more extensive involvement of the cervix.

The most common type is a lobular variant.

PAX8, GATA3, and CD10 (+); calretinin 10% (+); ER, PR, p16, and p53 (−)

Activating KRAS and NRAS mutations are not found.

Mesonephric adenocarcinoma, endometrial adenocarcinoma with invasion of the cervical stroma, endocervical adenocarcinoma

Mesonephric adenocarcinoma

The vast majority of cases arise in the uterine cervix. Represents less than 1% of all carcinomas at this site.

Patients commonly present with abnormal bleeding and/or an exophytic polypoid mass protruding into the cervical canal.

Firm mass in the lateral wall of the cervix.

Diffusely thickened cervix may be an alternative presentation.

Often widely infiltrative.

May display a variety of patterns: ductal, tubular, solid, papillary, retiform, and sex cord–like. Depending on the pattern, epithelial cells may be cuboidal or columnar.

Rare cases are biphasic tumors, which disclose a sarcomatoid component.

CD10, CK7, PAX2, and PAX8 (+); GATA3 (+), but to a lesser extent compared with GATA 3 results in MRs and MH; TTF-1, calretinin, and inhibin are variably (+); CEAm, ER, and PR (−)

Canonical activating KRAS mutations, NRAS mutations, gain of 1q, no microsatellite instability. TP53 mutations are variably present.

Mesonephric hyperplasia, endometrioid adenocarcinoma, mesonephric-like adenocarcinoma, clear-cell carcinoma, serous carcinoma