EP509 Case series of uterine sarcomas associated with preoperative treatment with ulipristal acetate for supposed symptomatic myomas

Introduction/Background Ulipristal acetate is used for preoperative treatment of symptomatic uterine myomas. The diagnosis of uterine myomas is usually clinical and might miss uterine sarcomas. Methodology The clinical audit of the regular clinical database of our Department for Gynecologic and Breast Oncology, Maribor, Slovenia, showed in last 6 years a series of three patients with different sarcomas in association with preoperative treatment with ulipristal acetate. All patients were followed, diagnosed and treated outside of our department and referred after the final diagnosis. Results The first patient was a 50-years old XY1 who was followed for a symptomatic uterine myoma for years. She was a former infertility patient. Since the persistent bleedings she was put on ulipristal acetate, the tumour grew, laparoscopic myomectomy was performed. The histological report described a low grade endometrial stromal sarcoma. The second was a 27-years old XY2 who was presented to reproductive medicine gynaecologist for infertility and uterine myomas. MR of the abdomen revealed numerous extrauterine and uterine myomas. She was put on ulipristal acetate for preoperative treatment. Again, the tumours grew. She was operated, having abdominal myomectomy, and one of the pelvic tumours was histologically STUMP. The third patient was a 54-years old XY3 who was also followed for a supposed myoma, put on ulipristal acetate, again the tumour grew and laparoscopic hysterectomy followed. The histology revealed leimyomsarcoma. Conclusion Our clinical audit showed a series of three different sarcomas associated with preoperative treatment with ulipristal acetate. All three patients were followed for a supposed myomas years before treatment. It is not possible to conclude if the tumours were sarcomas from the beginning or there was a malignant transformation/tumour growth promotion after introducing ulipristal acetate. Our results warrant a research of larger rare tumours databases. Disclosure Nothing to disclose.