To explore the clinical characteristics and risks of ovarian endometrioma (OMA) malignancy complicated with pelvic abscess in pregnant women after in vitro fertilization-embryo transfer (IVF-ET) treatment.

A retrospective analysis was conducted on a case of a 31-year-old pregnant woman with malignant transformation of right OMA complicated with pelvic abscess after IVF-ET assisted reproduction (patient 1) admitted to the Obstetrics and Gynecology Department of Tianjin Medical University General Hospital in January 2017. The medical history, diagnosis and treatment process, and prognosis of patient 1 were analyzed. The relevant research literature on OMA malignancy complicated with pelvic abscess in pregnant women was retrieved using the keywords " malignant transformation of ovarian endometrioma" " in vitro fertilization and embryo transfer" " pelvic abscesses" and " reproductive age", in both Chinese and English in the CNKI, Wanfang Data Knowledge Service Platform, and PubMed database. This study complied with the ethical standards formulated by the Ethics Committee of Tianjin Medical University General Hospital (Approval No. IRB2023-WZ-156). Informed censent was obtained from patient 1.

① After undergoing total hysterectomy + bilateral salpingo-oophorectomy + omentectomy + pelvic and para-aortic lymph node dissection, Patient 1 was diagnosed with malignant transformation of right OMA (endometrioid adenocarcinoma stage ⅡB) and pelvic abscess. Patient 1 developed complications such as incomplete intestinal obstruction, moderate anemia, hypoalbuminemia, and drug-induced liver injury after surgery, and was discharged from the hospital after 7 weeks of treatment. Patient 1 received six cycles of chemotherapy with docetaxel + carboplatin after surgery, and follow-up for 6.5 years showed no recurrence of right ovarian endometrioid adenocarcinoma. ② According to the literature retrieval strategy developed in this study, no literature reports were found on the study of OMA malignancy complicated with pelvic abscess in women of reproductive age.

Clinicians should be alert to the possibility of OMA malignancy in women of reproductive age, and early diagnosis of OMA should be made to avoid the occurrence of OMA malignancy complicated with pelvic abscess after patients enter the IVF-ET cycle. Patients with OMA should actively prevent the risk of pelvic abscess after IVF-ET assisted reproduction. Multidisciplinary team collaboration plays an active role in the diagnosis and treatment of these patients.