Right-Sided Ovarian Cysts More Likely to Resolve


From the annual meeting of the North American Society for Pediatric and Adolescent Gynecology

Major Finding: In adolescents, ovarian cysts on the left side are 116 times less likely to resolve spontaneously than those on the right.

Data Source: Retrospective analysis of data from 151 patients aged 13-18 years.

Disclosures: None was reported.

LAS VEGAS — It's well known that most ovarian cysts in adolescents resolve spontaneously, but for some unknown reason, those on the right side are far more likely to resolve than those on the left, a retrospective study of 151 teenaged girls showed.

Investigators at the University of Missouri–Kansas City determined that after adjusting for potential confounders, cysts on the left side were 116 times less likely to resolve without surgery than those on the right.

“It was kind of a surprising finding,” coauthor Dr. Jeffrey Wall said in an interview. “You'd think that a right- or left-sided cyst wouldn't matter. It would spontaneously regress independently [of side]. But we found that a right-sided cyst was a predictor of cyst resolution.”

Dr. Wall and lead author Dr. Timothy Chad McCormick conducted the study by reviewing charts from 2000 to 2008 of all adolescent females with a diagnostic ICD-9 code consistent with an ovarian cyst or mass. There were 342 such patients. For the purposes of the study, the investigators included only 151 of those patients—those who had been followed until documented resolution or who underwent surgical intervention for nonresolution.

Of those patients, 91 (60%) had their cysts resolve spontaneously, while the others required surgery.

The investigators conducted a multivariate regression analysis that adjusted for age at diagnosis, race, cyst size, cyst volume, cyst side, and cyst complexity. Only two factors emerged as statistically significant independent predictors of resolution: cyst side and cyst size. The odds ratio for left-sided cysts was 116.39, indicating a far greater risk for left-sided cysts than for those on the right. The odds ratio for right cyst size was 0.42, indicating that right-sided cysts under 7 cm in size were 58% more likely to resolve spontaneously than larger right-sided cysts.

Dr. Wall said that the investigators have no explanation for their unusual findings, and that they intended to take a closer look at patient charts to see if they can identify any hypotheses.

Asked whether he would treat patients with left-sided cysts any differently as a result of this study, Dr. Wall said that he would not, at least not yet. “This was a new finding for us. It was unexpected,” he said. “I would say [that physicians should] continue to manage them as they normally would. I would still observe them for a period of time. But if it is on the right side, it's certainly something you can tell the family: It's right sided, so there's a better chance. It's a reassuring thing if nothing else right now.”

Also reassuring, he said, was that the study confirmed that most ovarian cysts in adolescents do resolve spontaneously.

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