%0 Journal Article %A G Ricotta %A A Maulard %A P Pautier %A A Leary %A C Chargari %A S Gouy %A C Genestie %A P Morice %T 948 Brenner borderline ovarian tumor: a case series and literature review %D 2021 %R 10.1136/ijgc-2021-ESGO.532 %J International Journal of Gynecologic Cancer %P A304-A304 %V 31 %N Suppl 3 %X Introduction/Background*Most frequent borderline ovarian tumors are serous and mucinous subtypes. Less frequent borderline diseases are endometrioid, clear cell and Brenner tumors (BBOT). Very few are known about this later subtype and most of reports concerns very short series or case reports. The aim of this study was to determine the prognosis of a continuous series of BBOT and to analyze data published in the literature about this rare entity.Methodology A retrospective review of patients with BBOT treated or referred to our institutions. A centralized histological review by a reference pathologist and data on the clinical characteristics, management and outcomes of patients were required for inclusion.Seventeen patients were identified Median age was 62 (range 42-85) years. Six patients underwent a unilateral salpingo-oophorectomy and 11 a bilateral salpingo-oophorectomy +/- hysterectomy and/or staging surgery. Sixteen patients had unilateral tumor and all patients had a stage-I disease. Stromal microinvasion was observed in 3 cases. The median follow-up was 60 months (range 7-118 months). One patient had developed a recurrence in contralateral ovary after a unilateral salpingo-oophorectomy. One patient had previous history of urothelial tumor.Conclusion*Peritoneal staging surgery is not required, because all patients reported had stage-I disease. One recurrence occurred. When reviewing all the 82 cases reported in the literature (included ours), 9% had previous history or synchronous urothelial tumor suggesting then the need of at least careful checking of urological disease in patients with BBOT. %U https://ijgc.bmj.com/content/ijgc/31/Suppl_3/A304.2.full.pdf