ABSTRACT Nonpuerperal uterine inversion (NPUI) due to endometrial carcinosarcoma can present in an acute manner with life‐threatening complications. The rare presentation of uterine inversion outside of the puerperium caused by a malignant etiology, which was further complicated by the urgent need for intervention, makes this case crucial in recognizing the importance of expeditious management of NPUI. A 73‐year‐old nulliparous woman was referred to our gynecological oncology service following a diagnostic hysteroscopy and biopsy, which had identified a 10 cm polyp that was reported to be a high‐grade serous carcinosarcomatous polyp. Only 20 days after the initial diagnosis was made, the patient experienced an intensification of her symptoms with an increased volume of per vaginal bleeding, oliguria, and vomiting. Examination revealed a tender mass protruding through the vaginal introitus that was noted to be malodorous. The patient was admitted urgently for stabilization of both an acute kidney injury (AKI) due to urinary retention caused by the obstructing mass and anemia due to the extent of her per vaginal hemorrhage. Surgical management was expedited, and the patient underwent a modified type III radical hysterectomy, bilateral salpingo‐oophorectomy, bilateral pelvic lymphadenectomy, and omentectomy. This case required the employment of expert gynecological oncological techniques for optimal patient management. We believe that our identification of such an exceptional case in terms of both the presentation of endometrial carcinosarcoma as NPUI and as an emergency will inform future management of acute presentations of gynecological malignancy.