Abstract: Struma ovarii is an ovarien teratoma which predominantly contains thyroid tissue. Because of its rarety, the diagnosis and the managment of the tumour have not been clearly defined. We report a case of malignant papillary struma ovarii not suspected in preopertive. The chirurgical treatment of our patient was total hysterectomie, bilateral salpingo-oophorectomie and biopsies comleted with thyroidectomie and radioactive iodine ablation wish was decided in multidisciplinary consultation meeting. Through this observation, we discuss the diagnositic, management and outcome features of these particular tumors.