Introduction/Background Ovarian masses (whether benign or malignant) are rare in children. They count 2.6 cases per 100,000 girls per year and 50% of them are malignant. Because of the young age of the patient the decision for radicality of the surgery is usually difficult.

Methodology We present retrospective analysis of children and adolescent girls with adnexal mass operatively treated from 2013 to 2022 in University Medical center Ljubljana, where we operated all of ovarian malignant tumors in children in Slovenia. Clinical presentation, intraoperative procedures, histopatologic findings and postoperative follow up were collected from medical records and analyzed.

Results In period of 10 years 69 young patients with ovarian mass were operated, 15 of them were malignant, 54 had benign histology. Median age of the patients with malignant tumors was 14,2 years, with benign tumors was 16,1 years. In the malignant group there were 6 borderline tumors, 2 immature teratomas, 3 disgerminomas (2 of them siblings with Swayer syndrom), 2 yolk sac tumors, 1 sclerosating stromal tumor and 1 Sertoli Leydig cell tumor. Benign masses were devided into 19 mature teratomas, 6 paraovarian cysts, 12 cystadenomas (6 serouse, 6 mucinous), 3 cistadenofibromas (2 serous, 1 mucinous), 1 endometrioma, 1 ovarian fibroma and 14 functional cysts. 28 from the patients with benign masses had torsion. All the patients had fertility spearing surgery. Four patients with malignant histolgy had adjuvant chemotherapy (2 disgerminomas and 2 yolk sac tumors), one patient with yolk sac tumor had early relapse and second line chemotherapy. Until now all of the patients are in remission.

Conclusion Fertility spearing operation in children with ovarian mass is feasible and could be the treatment of choice, as it preserves reproductive potential.

Disclosures Authors have no disclosures.