Abstract
Primary retroperitoneal mucinous cystic tumors with borderline malignancy are rarely encountered. To date, only 12 cases have been reported in the literature. In this report, we present an additional case. A 65-year-old nulliparous woman complained of abdominal fullness. Her medical history included a hysterectomy and a single salpingo-oophorectomy performed 25 years prior to the present event. Physical examination revealed a large cystic mass in the abdomen and pelvis. During laparotomy, a cystic tumor measuring 21 × 14 cm in size was observed in the left retroperitoneal space. The tumor was resected, and the final diagnosis was primary retroperitoneal mucinous cystic cancer with borderline malignancy.