An Incidental Finding of Low-Grade Appendiceal Mucinous Neoplasm in a Case of Borderline Brenner Tumor of the Ovary

The concurrent presentation of a low-grade appendiceal mucinous neoplasm (LAMN) and a borderline Brenner tumor (BT) of the ovary are exceedingly rare. Brenner tumors stand out as a particularly uncommon form, making up only around 5% of all benign epithelial tumors of the ovary. Among the ovarian Brenner, the borderline subtype is even rarer. Appendiceal neoplasm (LAMN) and right ovarian BT cannot be distinguished due to their anatomical position. LAMN is often an incidental finding and at later stages when left undiagnosed may lead to pseudomyxoma peritonei (PMP). This case describes a postmenopausal woman in her 50s experiencing abdominal pain and bloating for a week. Elevated carcinoembryonic antigen (CEA) levels and imaging suggested a potential right ovarian tumor. Interestingly, it revealed a unique combination of borderline Brenner tumor of the right ovary and low-grade appendiceal mucinous neoplasm.