Risk of malignancy in sonographically confirmed septated cystic ovarian tumors

Objective: To determine the risk of malignancy in septated cystic ovarian tumors. Materials: 1319 (4.4%) of 29,829 women were identified by transvaginal sonography (TVS) as having a complex cystic ovarian tumor with septations without solid areas or papillary projections and were placed on long-term ultrasound surveillance for ovarian malignancy. Results: These 1319 patients had a total of 2870 septated cystic ovarian tumors. 2288 tumors (79.7%) had a septal width < 2 mm and 582 (20.3%) had a septal width ≥ 2 mm. 2286 tumors (79.6%) were < 5 cm in diameter and 584 (20.4%) were ≥ 5 cm in diameter. 1114 septated cystic tumors (38.8%) resolved spontaneously (mean duration to resolution-12 months) and 1756 (61.2%) tumors persisted. 128 patients underwent surgical tumor removal within 3 months of ultrasound. Most common histopathology was: serous cystadenoma (75), mucinous cystadenoma (13), and endometrioma (10). One patient had an ovarian tumor of borderline malignancy (Stage IB). There were no cases of ovarian cancer. Patients were followed from 4 to 252 months (mean-77 months). One patient developed papillary morphology in the contralateral ovary 3.2 years after detection of a septated ovarian cyst and had epithelial ovarian cancer in that ovary and in the omentum (Stage IIIC disease). The remaining patients are all free of ovarian neoplasia after a total of 7642 follow-up years. Conclusions: Septated cystic ovarian tumors without solid areas or papillary projections have a low risk of malignancy and can be followed sonographically without surgery.