16 – 19 September 2017, Vienna, Austria Poster discussion hub abstracts Methods: From a group of consecutive patients suspected for ovarian cancer (OC) (symptoms, ascites, elevated cancer antigen (CA) 125) and who underwent laparotomy, 14 had PPC (tumour disseminated on the peritoneum without or with only minimal ovaries involvement). Before surgery all patient underwent standardised transvaginal and abdominal ultrasound examination with predefined definitions (images and videos stored) so to calculate RMI, LR2, ADNEX, SR. A subjective assessment was to discriminate between malignant and benign disease in a 6 point score. Results: High RMI was assessed in all cases. Tumours were classified as malignant (n=3) or inconclusive (n=11) with IOTA-SR. Median value of LR2 was 75.1% (range: 34.7-94.9). Median values of ADNEX model calculations were as follows: risk of malignancy-98.6% (range: 85.6-99.9), risk of stage II-IV OC-89.9%, risk of stage I OC -1.1%, risk of borderline tumour-0.45%, risk of metastatic cancer-7.4%. Once ADNEX model was calculated without CA125, in all cases with ascites the risk of malignancy was still over 91%, while in patients without ascites (n=3) this value was 58-63%. In subjective assessment all patients were suspected for malignancy. There were no pelvic tumours with locules, nor with papillations. Ascites and metastatic tumours in abdominal cavity were detected in 11 and 12 patients respectively. Median ultrasound diameter of ovaries or ovarian involvement was 34mm. Median concentration of CA125 was 928 U/ml (98-7000). Conclusions: In cases with PPC, the RMI, ADNEX model and subjective ultrasound assessment can predict malignancy with a very high accuracy. Evaluation of CA125 should be considered, both as a single diagnostic measure and a part of ADNEX model. IOTA-SR has limited value in diagnosing PPC. P30.03 Imaging in gynecological disease: clinical and ultrasound features of ovarian endometrioid carcinoma F. Moro 8 , G. Magoga 8 , T. Pasciuto 8 , A. Di Legge 8 , M. Moruzzi 8 , D. Fischerov ´ a 9 , L. Savelli 7 , A. Czekierdowski 6 , D. Timmerman 5 , W. Froyman 5 , D. Verri 10 , E. Epstein 2 , V. Chiappa 3 , S. Guerriero 4 , L. Valentin 1 , A.C. Testa 8 1 Sk˚ ane University Hospital Malm ¨ o, Lund University, Malmo, Sweden; 2 Department of Clinical Science and Education, S¨ odersjukhuset and Department of Women’s and Children’s Health Karolinska Institutet, Stockholm, Sweden; 3 Gynecologic Oncology, National Cancer Institute of Milan, Milan, Italy; 4 Department of Obstetrics and Gynecology, University of Cagliari, Cagliari, Italy; 5 Department of Development and Regeneration, KU Leuven; Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium; 6 First Departmentof Gynecological Oncology, Medical University of Lublin, Lublin, Poland; 7 Obstetrics and Gynecology, Gynecologic and Early Pregnancy Ultrasound Unit, Bologna, Italy; 8 Obstetrics and Gynecology, Catholic University of the Sacred Heart, Rome, Italy; 9 Gynecological Oncology Centre, Department of Obstetrics and Gynecology, First Faculty of Medicine, Charles University, Prague, Czech Republic; 10 Department of Obstetrics and Gynecology, University of Milan-Bicocca, San Gerardo Hospital, Monza, Italy Objectives: To describe clinical and ultrasound features of ovarian endometrioid carcinoma. Methods: Patients with a histological diagnosis of ovarian endometrioid carcinoma, who had undergone preoperative ultra- sound, were retrospectively identified from 10 ultrasound cen- tres. The masses were described using the terms of the IOTA group. Results: 192 patients with a diagnosis of endometrioid car- cinoma were identified. Median age of the patients was 56 (range,19-88) years. Most of the staged cases were FIGO Stage I (n=113/191,59.2%) and the vast majority of the tumours having an available grading were of grading 1 or 2 (n=124/172,72%). Forty (20.8%) cases were associated with endometriosis. On ultra- sound, 2 (1%) carcinomas were unilocular, 2 (1%) multilocular, 34 (17.7%) unilocular-solid, 89 (46.4%) multilocular-solid and 65 (33.9%) solid masses. The median of the largest diameter of the lesion was 104 (range 20-300) mm. Papillary projections were present in 61 (31.8%) masses. The echogenicity of cyst fluid was anechoic in 27 (14.1%) cases, low level in 72 (37.5%), ground glass in 17 (8.9%), hemorrhagic in 2 (1%) and mixed in 10 (5.2%), whereas 64 (33.3%) cases had no cyst fluid. 149 cases (77.6%) were unilateral. Conclusions: Primary ovarian endometrioid cancer was most commonly found between the fifth and sixth decade, associated with endometriosis in one fourth of patients. Endometrioid cancers were usually low risk ovarian cancers presenting in an early stage as large, unilateral, multilocular-solid tumours or solid mass. Supporting information can be found in the online version of this abstract P30.04 Does rectal enema improve the accuracy of ultrasonography in predicting rectosigmoid infiltration in patients with ovarian cancer? S. Ferrero 1,2 , C. Bondi 1 , F. Laraud 1 , F. Barra 1 , C. Scala 1,2 , P.L. Venturini 1 , V. Vellone 3 1 Academic Unit of Obstetrics and Gynecology, IRCCS AOU San Martino-IST, University of Genova, Genoa, Italy; 2 Piazza della Vittoria 14 SRL, Genoa, Italy; 3 Department of Surgical and Diagnostic Sciences, IRCCS AOU San Martino-IST, University of Genova, Genoa, Italy Objectives: To investigate the accuracy of ultrasound with and without rectal enema in predicting rectosigmoid infiltration in patients with epithelial ovarian cancer (OC). Methods: This prospective study included 52 patients with epithelial OC who underwent primary surgery. Carcinomatosis was defined as a nodular or sheet-like hypoechoic structure, vascularised, attached to the peritoneum of the rectosigmoid or invading into the muscularis propria. Both superficial carcinomatosis and nodules invading the bowel wall were considered rectosigmoid infiltration. The depth of Infiltration of the intestinal wall was assessed. One ultrasonographer performed the exam without rectal enema. Another ultrasonographer blinded to the findings of the first investigator performed the scan only after distention of the rectosigmoid wall (200-350 ml of saline solution slowly injected inside the rectosigmoid). Results: Surgery and histology revealed rectosigmoid infiltration in 24 patients (46.2%). The diagnostic performance of ultrasonography without rectal enema was sensitivity 75.0%, specificity 92.9%, positive likelihood ratio 10.50, negative likelihood ratio 0.27, positive predictive value 90.0%, negative predictive value 81.3%. The diagnostic performance of ultrasonography with rectal enema was sensitivity 87.5%, specificity 96.4%, positive likelihood ratio 24.50, negative likelihood ratio 0.13, positive predictive value 95.45%, negative predictive value 90.0%. The Mc Nemar’s test revealed there was no significant difference between the two techniques in diagnosing rectosigmoid infiltration (p=0.134). Similarly, rectal enema did not increase the accuracy of ultrasound in discriminating superficial carcinomatosis or infiltration reaching at least the muscularis propria (p=0.578). The patients reported that ultrasonography without enema was less painful that ultrasonography with enema (p<0.001). © The Authors 2017 © Ultrasound in Obstetrics & Gynecology 2017; 50 (Suppl. 1): 154–256. 253