Introduction/Background Ovarian Sertoli-Leydig cell tumours (SLCTs) are a rare, sex cord-stromal ovarian tumours that mostly affect young women that represent less than 0.5% of all ovarian tumours. They have a very poor prognosis since its relapse rate is up to 95% within 5 years after the diagnosis. . Clinical management of SLCTs remains a critical challenge due to the limited available data and clinical experience.

Methodology We report a case of a 29 year-old-women diagnosed of a SLCT FIGO stage IC2 after a left adnexectomy due to an ovarian torsion. As there was no evidence of peritoneal disease at the time of surgery, adjuvant chemotherapy with carboplatin was proposed. The treatment was stopped after 4 cycles because the patient became pregnant. Pregnancy developed correctly without maternal or foetal complications. 17 months after initial diagnosis, patient had an emergency laparoscopy for a hemoperitoneum associated with a giant multilobulated adnexal mass of 11 cm, dependant of the stump of the tube remaining from the previous adnexectomy. A poorly differentiated SLCT was confirmed. A PET-TC was performed and hypermetabolic images which could not discard malignancy were detected. A peritoneal carcinomatosis was confirmed by laparoscopy.

Results Because of the rarity of these tumours, therapeutic approach was decided based on previous reports and after discussing different options in a multidisciplinary setting jointly with the patient. Finally a complete cytoreductive surgery was performed and adjuvant chemotherapy was offered

Conclusion Due to scarcity of data on SLCTs there are not evidence-based treatment guidelines, resulting in diverse management strategies. Shared - decision making is essential in order to assess risks and benefits of the therapeutic approach.

Disclosures Authors declare no disclosures.