The epithelial tumors of the ovary are very varied in nature, they often pose difficult diagnostic problems: on the one hand to assert their organicity so as not to overtreat a functional lesion and on the other hand to appreciate their benign or malignant nature. Among them, we can mention the ovarian fibroma which is a rare tumor representing less than 1% of all ovarian tumors. Cases of cystic degeneration of this fibroma simulating ovarian cancer are described in the literature. We report a case of this type of degeneration affecting ovarian fibroma and taken for ovarian cancer, despite the explorations in medical imaging, but considering the appearance of the mass and the absence of peritoneal carcinomatosis at the exploratory laparotomy, a Limited excision was recommended pending the results of the pathological examination in the diagnosis of this malformation. Through this observation, we will analyze the symptomatology of this clinical form which mistakenly mimics an ovarian cancer and also discuss the interest of ultrasound and the determination of tumor markers in the diagnostic approach as well as the therapeutic attitude to adopt in this clinical form