The most fatal gynecologic cancer is ovarian cancer. The most prevalent kind of ovarian cancer is the surface epithelial tumour. 15–20% of ovarian cancers among these are mucinous tumors. One of the most challenging ovarian neoplasms for surgical pathologists to understand is mucinous ovarian tumors. Other surface epithelial cancers can occasionally coexist with mucinous tumors. Making a correct diagnosis of mucinous tumors is so crucial. However, Brenner tumors seldom occur in conjunction with other neoplasms. Due to its rarity and contested histogenesis, ovarian Brenner tumor has traditionally been regarded by pathologists as a perplexing tumor. In this case report, we present a benign Brenner component in a large mucinous cystadenoma.