Management of Physiologic Adnexal Cysts in Asymptomatic Adult Women
For asymptomatic adult women with physiologic (simple) adnexal cysts, most require no follow-up imaging, with specific size thresholds determining management based on menopausal status. 1, 2
Premenopausal Women
Simple cysts ≤5-7 cm require no follow-up imaging. 2
- Simple cysts establish a benign process in 100% of premenopausal women when properly characterized on ultrasound 1
- Most physiologic cysts in premenopausal women are functional and resolve spontaneously 1
- Report simple cysts only if >3 cm to document their presence in the medical record, but follow-up imaging is recommended only for cysts >5-7 cm 2
- The higher 7-cm threshold applies when the cyst has excellent imaging characterization and documentation 2
Postmenopausal Women
Simple cysts ≤3-5 cm require no follow-up imaging. 1, 2
- Simple cysts occur in 17-24% of postmenopausal women and carry near-zero malignancy risk (0-0.5 cases per 10,000 women over 3 years), similar to women with normal ovaries 1, 3
- The 2019 Society of Radiologists in Ultrasound consensus raised the follow-up threshold from the previous 1 cm to >3 cm (or 5 cm for exceptionally well-visualized cysts) 1
- In prospective studies, 53% of postmenopausal simple cysts disappeared completely, 28% remained stable, and only small percentages showed size changes 1
- Report simple cysts >1 cm to document their presence, but follow-up is only recommended for cysts >3-5 cm 2
Initial Imaging Approach
Transvaginal ultrasound combined with transabdominal ultrasound and color Doppler is the essential first-line imaging modality. 1, 4
- Color or power Doppler must be included to evaluate vascularity and confirm absence of solid components 1
- Transabdominal ultrasound provides optimal assessment when transvaginal approach cannot be tolerated or for large masses 1
- The entire mass must be visualized well to confidently diagnose a simple cyst and apply these guidelines 5
Follow-Up Protocol (When Indicated)
If follow-up is performed, reassess at 6-7 months initially, then at 2 years if stable. 4, 2
- If a cyst is at least 10-15% smaller at any time, further follow-up is unnecessary 2
- Stable simple cysts at initial follow-up benefit from a 2-year follow-up due to measurement variability that could mask growth 2
- Simple cysts that grow are likely benign cystadenomas but warrant continued surveillance 2
- If previously suspected simple cyst develops papillary projections or solid areas at follow-up, reclassify using standardized terminology and consider MRI 2
When to Escalate Imaging
MRI pelvis with IV contrast is the next imaging study when ultrasound features are indeterminate or the mass cannot be optimally visualized. 4, 1
- Contrast-enhanced MRI performs superiorly to both ultrasound and noncontrast MRI for confirming presence of internal enhancing soft tissue components 1
- Classical benign lesions (simple cysts, endometriomas, dermoids) have characteristic MRI appearances and can be confidently diagnosed as almost certainly benign 1
- CT has no role in characterization or follow-up of benign adnexal masses 1
Critical Pitfalls to Avoid
Do not assume all postmenopausal cysts are malignant - simple and minimally complex cysts have very low malignancy rates even after menopause, with large screening studies demonstrating near-zero cancer risk 1, 4
Do not rely on CA-125 for characterization - this marker performs worse than ultrasound for distinguishing benign from malignant lesions and may be low in borderline and low-grade malignancies 4, 3
Do not mistake pedunculated fibroids for ovarian masses - always identify normal ovaries separately and trace blood supply from uterine vessels, as pedunculated leiomyomas are the most common solid adnexal masses in postmenopausal women (20-30%) 4, 3
Do not perform unnecessary follow-up imaging - the updated guidelines specifically aim to limit unnecessary imaging to save patients time, money, and anxiety while maintaining safety 5, 2