Management of Ovarian Cysts
For premenopausal women with simple cysts ≤5 cm, no follow-up imaging is needed—these are physiologic and benign in 98.7% of cases. 1, 2
Initial Assessment and Cyst Characterization
The foundation of management depends on accurate ultrasound characterization using transvaginal combined with transabdominal imaging. 3 A simple cyst must meet strict criteria: completely anechoic fluid, thin smooth walls without thickening, no septations, no solid components or nodularity, and no vascularity on color Doppler. 1 Any deviation from these features—septations, solid components, wall irregularity, or internal vascularity—classifies the cyst as complex and requires different management. 1
Management Algorithm by Menopausal Status and Cyst Size
Premenopausal Women
Simple Cysts:
≤5 cm: No follow-up required; these represent physiologic follicles or corpus luteum cysts that resolve spontaneously within 1-2 menstrual cycles. 1, 2 The malignancy risk is essentially zero—no simple cysts were diagnosed as cancer among 12,957 cysts in women under 50 years. 1
>5 cm but <10 cm: Follow-up ultrasound at 8-12 weeks, preferably during the proliferative phase (after the next menstrual period), to confirm functional nature or assess for wall abnormalities. 1, 2 Most will resolve; if persistent or enlarging, refer to gynecology. 1
≥10 cm: Surgical management indicated regardless of appearance. 1, 4
Hemorrhagic Cysts:
- ≤5 cm: No further management needed; these functional cysts decrease or resolve on follow-up at 8-12 weeks. 1
Endometriomas and Dermoid Cysts:
- Optional initial follow-up at 8-12 weeks, then yearly ultrasound surveillance if stable. 1 Endometriomas require yearly monitoring due to small malignant transformation risk, particularly as they can change appearance with age. 3, 1
Postmenopausal Women
Simple Cysts:
≤3 cm: No further management required; malignancy risk is essentially zero. 1 Studies show only 1 malignancy among 2,349 simple cysts in women over 50 at 3-year follow-up. 1
>3 cm but <10 cm: At least one follow-up ultrasound at 1 year to confirm stability, with consideration for annual surveillance up to 5 years if stable. 1 During follow-up, assess for size increase, development of solid components, septations, wall irregularities, or new vascularity. 1 Research supports this conservative approach—in one study of 619 postmenopausal women with simple cysts, 46% resolved spontaneously and 44% persisted unchanged, with only one patient developing malignancy (0.16%). 5
≥10 cm: Surgical management indicated. 1
Complex Cysts:
- Surgical management recommended for postmenopausal women with complex features. 1
Hemorrhagic Cysts:
- Require further evaluation by ultrasound specialist, gynecologist referral, or MRI—these are uncommon in postmenopausal women and warrant heightened suspicion. 1
Risk Stratification Using O-RADS Classification
The Ovarian-Adnexal Reporting and Data System (O-RADS) provides standardized risk stratification that should guide management decisions: 1
- O-RADS 1-2 (almost certainly benign, <1% malignancy risk): No follow-up or surveillance only. 1
- O-RADS 3 (1% to <10% malignancy risk): Management by general gynecologist with consultation from ultrasound specialist or MRI examination. 1
- O-RADS 4 (10% to <50% malignancy risk): Consultation with gynecologic oncology prior to removal or referral for management. 1
- O-RADS 5 (50%-100% malignancy risk): Direct referral to gynecologic oncologist. 1
Tumor Markers and Additional Testing
Serum CA-125 should be measured before surgery in postmenopausal women with concerning features, but is not indicated for benign-appearing simple cysts in premenopausal women, including adolescents. 1, 4 Other markers (CEA, CA19.9) should only be measured if CA-125 is not elevated. 1
MRI with contrast serves as a problem-solving tool when ultrasound findings are indeterminate, achieving 85% sensitivity and 96% specificity for detecting malignancy. 1 CT is not useful for characterizing indeterminate adnexal masses, and PET/CT cannot reliably differentiate benign from malignant lesions. 1
Critical Pitfalls to Avoid
Do not operate prematurely on simple cysts <10 cm without appropriate observation—the malignancy risk in unilocular cysts in premenopausal women is only 0.5-0.6%, derived from surgical cohorts that likely overestimate risk. 3, 1, 4 Research confirms zero malignancies among simple cysts in women under 50. 1
Do not over-image functional cysts—the most common error is ordering unnecessary follow-up ultrasounds for small simple cysts that are physiologic. 2 Cysts <3 cm should be considered follicles or corpus luteum rather than pathologic "cysts." 2
Do not assume persistent cysts are pathological—many benign neoplasms can be safely followed, with malignancy risk in classic benign-appearing lesions managed conservatively being <1%, and acute complications (torsion, rupture) occurring in only 0.2-0.4%. 3, 1
Avoid fine-needle aspiration for cytological examination of solid or mixed ovarian masses—this is contraindicated. 1 Transvaginal aspiration is also contraindicated for purely fluid cysts >5 cm in postmenopausal women. 1
Special Populations: Adolescents
Management principles are identical to adult premenopausal women. 4 Simple cysts ≤5 cm require no follow-up, as most are functional and resolve spontaneously. 4 Counsel families that ovarian cysts are extremely common in menstruating girls, with about 7% of women having an ovarian cyst at some point, and the vast majority are physiologic. 4 Do not order tumor markers like CA-125 in adolescents with simple cysts. 4