Synchronous Ovarian and Endometrial Carcinomas; An Unusual Outcome of First Trimester Ultrasound Scanning. Karl McPherson, Rhona Lindsay, Jaimie Thiesen-Nash, Vanessa MacKay, Aradhana Mona Khaund, Smruta Shanbhag Background In the UK it is common practice that the first trimester dating scan also examines for the presence of gynaecological pathologies such as fibroids and ovarian cysts 1. We present an unusual case of synchronous ovarian and endometrial carcinomas in a postnatal 32 year old. The ovarian component was identified through our first trimester screening programme. She went into spontaneous preterm labour at 31 weeks gestation and delivered a live male infant by SVD. A postnatal MRI scan revealed thickening of the cyst wall, with a solitary nodule measuring 22x10x20 mm with multiple septae, of 11cm diameter. Her Ca 125 was elevated (47), RMI was less than 200. There was a family history of ovarian cancer. Histology revealed ovarian adenocarcinoma with lymphovascular space invasion and thus underwent staging laparotomy, with total abdominal hysterectomy, left salpingo- oophorectomy, infracolic omentectomy, bilateral pelvic lymph node dissection and para-aortic lymph node dissection with peritoneal washings. Synchronous G1 stage 2B endometriod ovarian adenocarcinoma originating in left ovary with right ovarian adenosquamous carcinoma and stage G1 Stage 1A endometriod endometrial carcinoma was found. She received 6 cycles of adjuvant Carboplatin and Paclitaxel chemotherapy. and no BRCA1/2 nor RAD51C/D mutations were found Discussion: Ovarian masses affect approximately 1- 4% of pregnancies. The vast majority of these are benign 1, with approximately 1:1000 pregnancies affected by ovarian malignancy. This case highlights the importance of antenatal screening at identifying gynecological pathologies. It is likely that there may be a heritable component to her development of these three synchronous carcinomas given her family history. It is also unusual that despite 3 synchronous carcinomas including an endometrial carcinoma that the patient was able to conceive. It is unclear whether this played a role in her pre-term labour. Following discussion at the local Gynaecological Oncology MDT a laparotomy, right salpingo-oophorectomy, peritoneal washings with omental and left ovarian biopsy, as the patient wished to retain her fertility. References: 1 Sessa C, Maur M. Ovarian cancers in pregnancy. Cancer and Pregnancy. Springer Berlin Heidelberg, Boulay R, Podczaski E. Ovarian cancer complicating pregnancy. Obstetrics and Gynaecology Clinics of North America. June :1 p Case Report 32 year old Para 1, presented in the first trimester of her 2nd pregnancy to tertiary obstetric unit for booking ultrasound scan and a unilocular right sided ovarian cyst was noted. There were no suspicious features and therefore conservatively managed. During this time it increased to a maximum diameter of 7cm, with an area suspicious for cyst haemorrhage.