Mucinous tumors make up 10% to 15% of all primary ovarian tumors. About 80% of those are benign and the remainder 20% consist of borderline tumors and carcinomas. The photograph shows an 11.0 cm diameter multilocular mucinous cystadenoma of the ovary that was filled with mucoid fluid. The lining was endocervical type. Image courtesy of : Ed Uthman, MD, Houston, Texas. Used with permission.