Ovarian carcinoma complicated by sigmoid colon fistula formation: a case report and review of the literature

Formation of a fistula to a digestive organ is an extremely rare phenomenon in cases of ovarian carcinoma. We report a case of ovarian clear-cell carcinoma complicated by formation of a sigmoid colon fistula, and review the related literature. A 61-year-old woman, who had undergone hysterectomy and right salpingo-oophorectomy due to myoma and an ovarian tumor, developed bloody bowel discharge and abdominal distention. Computed tomography revealed a huge pelvic tumor with a thickened wall and internal gas. As the patient also had severe anemia and peritonitis, emergency laparotomy was performed, and intraoperatively it was noted that the tumor was tightly attached to the sigmoid colon, and contained bloody pus. Left salpingo-oophorectomy was performed and pathological examination of the specimen revealed fistula formation between the ovarian tumor and the sigmoid colon. The tumor was diagnosed as left ovarian clear-cell carcinoma, but no diverticulum or direct tumor invasion was evident around the fistula. The patient was given chemotherapy with paclitaxel and carboplatin, and she is now doing well after 9 months with no evidence of tumor recurrence. Although fistulation to the digestive tract is very rare in cases of ovarian cancer, it must be diagnosed and treated promptly because severe inflammation can make it potentially life-threatening.