Abstract
Mesonephric carcinomas (MC) are rare malignant tumors in the mesonephric remnant of the uterine cervix. Recently, mesonephric-like adenocarcinomas (MLA), which share similar characteristics with MCs, have been classified in the 5th edition of WHO Classification of Tumors. The exact origin of MLA remains unclear, as they may either arise from the mesonephric tissue or represent Müllerian tumors that closely resemble MC. In this study, we present the case of a 28-year-old pregnant woman with an ovarian cyst. While we could not dismiss the possibility of malignancy, our primary suspicion was that the tumor
was an endometriotic cyst exhibiting decidualization based on the MRI image. Following consultation, we made the decision to carefully proceed with the pregnancy without resorting to surgery. During the caesarian section, we performed an ovarian cystectomy, revealing that the cyst was, in fact, an MLA coexisting with seromucinous borderline tumors located on the posterior aspect of the endometriotic cyst. This particular case provides further evidence supporting the notion that MLA represents a Müllerian adenocarcinoma demonstrating mesonephric differentiation. Differentiating between a malignant tumor and an endometriotic cyst with decidualization, during the gestational period poses a challenge. Moreover, the coexistence of MLA and seromucinous borderline tumors likely contributed to the difficulty in distinguishing between benign and malignant conditions. 〔Adv Obstet Gynecol, 76(1): 1-7, 2024(R6.2)〕
