Cystic Adnexal Lesions on Ultrasound
Reference Images
Initial Triage
First question
Apply only to nonpregnant, average-risk, asymptomatic patients with simple adnexal cysts on ultrasound.
Simple cyst criteria
- Unilocular, thin-walled, and anechoic.
- No septations, solid component, mural nodule, or papillary projection.
- No internal vascularity on Doppler.
Separate pathway
- Hemorrhagic cysts, endometriomas, dermoids, and other complex cysts are not managed with these simple-cyst thresholds.
- If not a simple cyst, manage separately with O-RADS or gynecologic evaluation as appropriate.
Premenopausal
Size thresholds
- 3 cm or smaller: often no need to report; if mentioned, may be called a follicle. No follow-up.
- Larger than 3 cm up to 5 cm: report presence/largest diameter; benign physiologic size range. No follow-up.
- Larger than 5 cm up to 7 cm: report all diameters; ultrasound follow-up in 2-6 months or 6-12 months.
- Larger than 7 cm: follow-up ultrasound and consider MRI if complete ultrasound characterization is difficult.
Follow-up behavior
- Decreased size: benign, no further follow-up.
- Similar over 12 months: benign simple cyst; consider one more follow-up at 2 years.
- Increased size: likely benign neoplasm; repeat ultrasound at about 1 year.
Postmenopausal
Size thresholds
- 1 cm or smaller: often no need to report; normal ovaries/adnexa. No follow-up.
- Larger than 1 cm up to 3 cm: report presence/largest diameter; benign inconsequential finding. No follow-up.
- Larger than 3 cm up to 5 cm: report all diameters; follow-up US in 3-6 months or 6-12 months, unless exceptionally well seen.
- Larger than 5 cm: follow-up US in 3-6 months or 6-12 months; consider further imaging if characterization is incomplete.
Follow-up behavior
- Decreased size: benign simple cyst, no further follow-up.
- Similar size: repeat at about 2 years from initial study to confirm longer-term stability.
- Increased size: enlarging simple cyst, likely benign neoplasm; repeat US at about 1 year.