<prompt> Mc benign epithelial ovarian tumor isSerous cystadenomaMucinous cystadenomaBrenner tumorOvarian fibroma  <response>: Serous cystadenoma and cystadenocarcinomaSerous cystadenoma and cystadenocarcinoma are amongst the most common of cystic ovarian neoplasms, accounting about 50 of all ovarian tumours; of these, 60-70 are benign, 15 borderline and 20-25 are malignant. 