[Proliferative lesions with mesonephric features in the gynecologic tract: a clinicopathological analysis of sixteen cases].

Objective: To investigate the clinicopathological features of proliferations with mesonephric features (PMF) of the gynecologic tract. Methods: A retrospective analysis was performed on the clinical and pathological data of 16 cases with PMF that were diagnosed from October 2016 to January 2022 at a single institution. The relevant literature was reviewed. Results: Among the 16 cases, with an average of 53 years (31-68 years), there were 5 cases of mesonephric hyperplasia, 4 cases of mesonephric adenocarcinoma and 7 cases of mesonephric-like adenocarcinoma. The five cases of mesonephric hyperplasia were located in the lateral wall of the cervix and composed of simple tubules with growth patterns of diffuse or lobular clusters, without obvious stromal reaction. Four cases of mesonephric adenocarcinoma consisted of a mixture of papillary, cribriform, solid and other architectures, the nuclei resembling these of papillary thyroid carcinoma, and strong fibroproliferative reaction. They were located deep in the cervical and vaginal stroma. One of the tumors showed atypical mesonephric hyperplasia adjacent to the tumor. Five uterine and two ovarian mesonephric-like adenocarcinoma cases had similar histological morphology with mesonephric adenocarcinoma, but no mesonephric remnants/mesonephric hyperplasia were found near the tumors. In addition, four (4/5) uterine mesonephric-like adenocarcinoma cases originated from the endometrium with secondary involvement of myometrium, including one case with clear demarcation between the normal endometrium and the neoplastic glands. One (1/5) uterine mesonephric-like adenocarcinoma case was mainly located in the deep myometrium, along with adenomyosis around the tumor, without mesonephric remnants. Two ovarian mesonephric-like adenocarcinoma cases were associated with endometriotic cyst/endometrioid cystadenoma, including one case with an abrupt transition between normal epithelium and atypical mesonephric cells within the single individual cyst directly adjacent to tumor. All mesonephric hyperplasia and mesonephric adenocarcinoma cases were positive for GATA3, PAX8 and CD10 in a varying degree, and negative for ER, PR and TTF1. Although mesonephric-like adenocarcinoma showed a considerable overlap of immunohistochemical expression with mesonephric adenocarcinoma, seven mesonephric-like adenocarcinoma cases were positive for TTF1 and negative for GATA3. Conclusions: PMF is a class of rare proliferative lesions with morphological and immunophenotypic characteristics of mesonephric duct. Its commonly involved site, microscopic morphology, associated benign and/or atypical lesions, and immunophenotype may contribute to its diagnosis and differential diagnosis.目的： 探讨女性生殖道具有中肾管特征的增生性病变（PMF）的临床病理学特征。 方法： 收集2016年10月至2022年1月首都医科大学附属北京妇产医院确诊的PMF病例16例，回顾性分析其临床病理资料，并复习相关文献。 结果： 16例患者，年龄31~68岁，平均年龄53岁。中肾管增生5例，中肾腺癌4例，中肾样腺癌7例。5例中肾管增生均位于宫颈侧壁，由简单小管呈弥漫或小叶状成簇生长，无明显的间质反应。4例中肾腺癌主体位于宫颈或阴道壁外侧，由乳头状、筛孔状、实性等多种结构混合，细胞核具有类似于甲状腺乳头状癌核特点，有显著的间质反应，其中1例（1/4）宫颈中肾腺癌周围伴局灶细胞非典型性的中肾管增生。5例宫体和2例卵巢的中肾样腺癌与中肾腺癌具有相似的形态学特征，但癌旁均未发现中肾管残件/中肾管增生。此外，4例（4/5）宫体中肾样腺癌由内膜面向肌层浸润，其中1例病变与正常子宫内膜腺上皮移行；1例（1/5）宫体中肾样腺癌位于深肌层，周围可见子宫腺肌症病灶；2例卵巢中肾样腺癌均伴子宫内膜异位囊肿/子宫内膜样囊腺瘤，其中1例可见异位子宫内膜腺上皮向异型中肾管样上皮过渡。所有中肾管增生和中肾腺癌病例均不同程度阳性表达GATA3、PAX8、CD10，阴性表达雌激素受体、孕激素受体及甲状腺转录因子1（TTF1）。尽管中肾样腺癌与中肾腺癌的免疫组织化学表达模式类似，但不同的是，所有7例中肾样腺癌均有TTF1的表达，并与GATA3存在反向染色。 结论： PMF是一类具有中肾管形态学和免疫表型特征的罕见的增生性病变谱系，其诊断与鉴别诊断依赖于对病变发生的部位、镜下形态、伴随的良性和/或非典型性病变以及免疫组织化学表达等方面的综合考量。.