Introduction/Background Malignant sex cord and stromal tumour of the ovary (malignant ovarian SCST) is a rare cancer representing around 5% of ovarian cancers, arising from granulosa, theca, Sertoli and Leydig cells or stromal fibroblasts, occurring at any age and manifesting as an abdominal or pelvic mass.

Methodology Retrospective study of 13 cases of malignant tumours of the sex cords and stroma of the ovary . These tumours were collected in the gynaecology and obstetrics I department of the Hassan II University Hospital in Fez over a period of 5 years, between November 2019 and November 2023

Results The diagnosis of these tumours is based on clinical data, especially hormonal manifestations, and is supported by imaging (ultrasound, CT scan) and the presence of tumour markers. Malignant tumours of the granulosa of the ovary produce inhibin A and B, which is useful for diagnosing and monitoring the disease. A FOXL2 mutation (3q23) has been found in most adult malignant granulosa tumours of the ovary. Chromosomal abnormalities have recently been detected among granulosa cell tumours, and include trisomy 12, monosomy 22 and chromosome 6 deletion. Diagnosis is confirmed by histological examination.

Conclusion Rare malignant ovarian tumours are chemosensitive, and the highest response rates have been obtained with combinations applied to germ cell tumours (BEP). A few cases of long disease-free survival have been reported in the metastatic phase, but the overall impact of chemotherapy on survival cannot be confirmed due to the long natural course of the disease and the rarity and heterogeneity of these tumours.

These tumours require long-term follow-up, as recurrence of the disease may occur after more than 10 years.

Disclosures Our study focuses on the clinical and biological manifestations, the histological types and the particularities of the management of these rare tumours.