The malignant potential of small cystic ovarian tumors in women over 50 years of age.

Objective: The aim of this study was to determine the risk of malignancy in cystic ovarian tumors < 10 cm in diameter in asymptomatic postmenopausal women or women >or =50 years of age.
Methods: All cystic ovarian tumors detected by transvaginal sonography screening in asymptomatic postmenopausal women or women > or =50 years of age were evaluated with respect to size and morphology. Histology was recorded on all tumors removed surgically. Follow-up data were available both on patients undergoing surgery and on those who elected to be followed without operative intervention.
Results: Unilocular cystic tumors were detected in 256 of 7705 patients (3.3%). All tumors were < 10 cm in diameter and 90% were < 5 cm in diameter. One hundred twenty-five of these cysts (49%) resolved spontaneously within 60 days and 131 (51%) persisted. Forty-five patients with persisting ovarian cysts underwent operative removal of these tumors. Thirty-two patients had ovarian serous cystadenomas, and the remainder had a variety of benign lesions. There were no cases of ovarian carcinoma in this group. Eighty-six patients with unilocular cystic ovarian tumors were followed at 3- to 6-month intervals without surgery, and none have developed ovarian cancer. Complex cystic ovarian tumors were detected in 250 patients (3.2%). All tumors were < 10 cm in diameter and 89% were < 5 cm in diameter. One hundred thirty-five (55%) resolved spontaneously within 60 days, and 115 (45%) persisted. One hundred fourteen of these patients underwent operative tumor removal. Seven patients had ovarian carcinoma, 1 had primary peritoneal cancer, and 1 had metastatic breast cancer to the ovary.
Conclusion: Unilocular ovarian cysts < 10 cm in diameter in asymptomatic postmenopausal women or women > or =50 years of age are associated with minimal risk for ovarian cancer. In contrast, complex ovarian cysts with wall abnormalities or solid areas are associated with a significant risk for malignancy. These data are important in determining optimal strategies for operative intervention in these patients.