Introduction/Background Uterus didelphys is a malformation of the female genital tract related to the abnormal embryonic development of the Mullerian ducts, resulting in duplication of the uterine body and cervix. Endometrial endometrioid adenocarcinoma is the main histological subtype related to endometrial cancer. It affects women mainly after menopause.

Methodology A Case Report of a Endometrioid adenocarcinoma of the endometrium in a didelphys uterus.

Results Woman, 64 years, nulligest, developed postmenopausal uterine bleeding in December 2022. A pelvic ultrasound describes an uterus with 128cm3, a thickened and heterogeneous endometrium measuring 1.3cm. An endometrial biopsy was performed using semiotic uterine curettage, with anatomopathological result of well-differentiated endometrioid adenocarcinoma.

Total abdominal hysterectomy, bilateral salpingo-oophorectomy and sentinel lymph node investigation with injection of patent blue into the cervix was perfomed. Intraoperatively, two endometrial cavities, as well as two uterine cervixes were found. On the right, a rudimentary cavity and cervix, as well as the presence of a septum in the proximal third of the vagina. Colored iliac sentinel lymph node was identified on the right, but wasn’t identified on the left, so a left pelvic lymphadenectomy was executed.

The final anatomopathological result revealed moderately differentiated endometrioid adenocarcinoma located in the left uterine cavity, with 50% invasion of the myometrium. Absence of neoplasic involvement in other structures: right endometrial cavity, right uterine cervix, left uterine cervix, vaginal margins, adnexes, lymph node right sentinel and left pelvic lymphadenectomy. Patient referred for clinical oncology evaluation, and underwent adjuvant brachytherapy. She maintains multidisciplinary follow-up, asymptomatic and without evidence of disease.

Conclusion Endometrial cancer is the main gynecological cancer in developed countries, whose main symptoms are related to postmenopausal bleeding. Data in the literature are scarce on the causality between Mullerian malformations and endometrial cancer. Among the few cases described in the literature, involvement of both uterine cavities is rare.

Disclosures We emphasize the importance of adequate evaluation of the two uterine cavities and cervix.