Premenopausal Women
Simple cysts
| Size | Recommendation |
|---|---|
| ≤3 cm | No follow-up |
| 3.1–5 cm | TVUS in 6–12 weeks; if simple and stable → annual TVUS × 1 year then discontinue |
| 5.1–7 cm | TVUS or MRI in 6–12 months; if stable → annual × 1 more year |
| >7 cm | MRI or surgical evaluation |
Hemorrhagic cysts
| Size | Recommendation |
|---|---|
| <3 cm | No follow-up |
| 3–5 cm | TVUS in 6–12 weeks to confirm resolution; if persistent → MRI |
Other lesion types
| Lesion Type | Size / Features | Recommendation |
|---|---|---|
| Endometrioma | ≤3 cm | No follow-up |
| Endometrioma | >3 cm | Annual TVUS; surgical referral if symptomatic or growing |
| Dermoid (mature cystic teratoma) | ≤3 cm | No follow-up |
| Dermoid | 3–5 cm | Annual TVUS; surgical referral if growing |
| Dermoid | >5 cm or atypical features | Surgical evaluation |
| Paraovarian / paratubal cyst | Simple, any size | Manage same as simple ovarian cyst by size |
| Polycystic-appearing ovaries | — | No imaging follow-up; clinical evaluation for PCOS if indicated |
| Complex lesion (thick walls, septations, mural nodule, solid component) | Any | MRI with and without contrast; Gyn-Onc referral if highly suspicious |
Postmenopausal Women
Postmenopausal ovaries should be atrophic. Any new lesion warrants lower-threshold evaluation than in premenopausal women. Simple cysts ≤1 cm are near-universal and require no follow-up.
Simple cysts
| Size | Recommendation |
|---|---|
| ≤1 cm | No follow-up (essentially universal finding; benign) |
| 1.1–3 cm | TVUS in 1 year; if stable/resolved → discontinue |
| 3.1–5 cm | TVUS or MRI in 6–12 months; if simple and stable → 1 additional year then discontinue |
| >5 cm | MRI; surgical evaluation |
Other lesion types
| Lesion Type | Recommendation |
|---|---|
| Hemorrhagic cyst (any size) | TVUS characterization; if persistent at 6–12 weeks → MRI and gynecology referral |
| New endometrioma | MRI and Gyn-Onc referral — new endometrioma in a postmenopausal woman requires evaluation for malignant transformation |
| Dermoid ≤3 cm, classic | TVUS follow-up; lower threshold for surgical referral vs. premenopausal |
| Dermoid >3 cm or atypical | Surgical evaluation |
| Complex / solid component (any size) | MRI with and without contrast; Gyn-Onc referral regardless of size |
CA-125 is not required for asymptomatic simple cysts. It may be obtained at clinical discretion for any complex or solid lesion, particularly in postmenopausal women.
Why This Matters
Adnexal cysts are among the most commonly encountered incidental findings on abdominal and pelvic CT. The vast majority are physiologic or benign. The ACR algorithm stratifies by menopausal status because the baseline risk of ovarian malignancy differs substantially — postmenopausal ovaries should not be forming new cysts, so a lower size threshold triggers follow-up. The complex/solid category bypasses size entirely: any solid component or thick irregular septation in a postmenopausal woman goes directly to Gyn-Onc referral.
Reference
Patel MD, Ascher SM, Paspulati RM, et al. Managing Incidental Findings on Abdominal and Pelvic CT and MRI, Part 1: White Paper of the ACR Incidental Findings Committee II on Adnexal Findings. J Am Coll Radiol. 2020;17(2):248–254.