Unilocular ovarian cysts common, rarely malignant: follow patients with serial ultrasound. (Postmenopausal Women).

NEW ORLEANS -- Unilocular ovarian cysts are fairly common but rarely malignant in postmenopausal women, and most can safely be followed conservatively with serial ultrasounds.

That finding emerged from a study of more than 15,000 women that was presented at the annual meeting of the Society of Gynecologic Oncologists.

Much smaller studies have recently suggested that the risk of malignancy with unilocular cysts is low. The current study is significant because of its large size and extended length of followup. Based on the strength of the current data, these cysts do not need to be removed solely to prevent malignancy, Dr. J.R. van Nagell, the study's lead investigator, said in an interview.

Removal may still be indicated if the cysts are causing pain or if their size is interfering with evaluation of the pelvis, added Dr. van Nagell of the University of Kentucky Lexington.

In, the current study, 15,106 asymptomatic women over age 50 years underwent ovarian cancer screening by transvaginal sonography. A total of 2,761 were diagnosed with at least one simple ovarian cyst less than 10 cm in diameter, said Dr. Frederick R Ueland, who presented the data at the meeting.

"There were no cases of ovarian carcinoma or Ovarian tumors developing malignant potential among these unilocular cysts," said Dr. Ueland of the university.

In fact, during the average 6.3 years of follow-up, nearly 70% of the 3,259 cysts detected resolved spontaneously, and 60% of those resolved within 3 months, he noted.