The natural history of adnexal cysts incidentally detected at transvaginal ultrasound examination in postmenopausal women.

Objective: To determine the natural history of adnexal cysts incidentally detected at transvaginal ultrasound examination and judged to be benign in postmenopausal women.

Methods: One hundred and thirty-four postmenopausal women referred for ultrasound examination and found to have an adnexal cyst judged to be benign and not causing any symptoms were followed with transvaginal ultrasound at 3, 6 and 12 months, and then every 12 months. The referring physician treated the patient at his/her own discretion.

Results: One hundred and sixty cysts were found, 121 (76%) being unilocular and 39 more complicated. Seventy-two cysts (45%) had a largest diameter of 3-19 mm and 88 (55%) had a largest diameter of 20-80 mm. Median follow-up time was 3 (range, 0.3-8) years. In twelve women (9%) the cysts were removed during follow-up, all their cysts (n = 14) being benign. The indication to operate was a change in cyst morphology or increased cyst size in five (4%) women. In 39 (29%) women, the cysts disappeared; in 18 (13%), new cysts developed; and, in 65 (49%), the number of cysts and their location remained unchanged. Regression of cysts was observed in 54% (33/61) of women < 60 years vs. in 8% (6/73) of those > or = 60 years (P = 0.0001). Ultrasound findings remained unchanged in 34% (21/61) of women < 60 years vs. in 77% (56/73) of those > or = 60 years (P = 0.0001).

Conclusions: The results support conservative management of adnexal cysts incidentally detected at transvaginal ultrasound examination and judged to be benign in postmenopausal women. Whether such cysts need to be followed-up at all and, if they do, how often and for how long, remains an open question.