Risk of Malignancy in 2 cm Septated Ovarian Cysts in Postmenopausal Women
According to the O-RADS US risk stratification system, a 2 cm septated ovarian cyst in a postmenopausal woman would be classified as O-RADS 3 (low risk) with approximately 1-10% risk of malignancy. 1
Classification and Risk Assessment
The risk of malignancy in ovarian cysts depends on several factors:
- Cyst characteristics: Septated cysts have higher risk than simple cysts
- Patient age: Postmenopausal status increases risk
- Size: 2 cm is relatively small, which is favorable
According to the American College of Radiology Ovarian-Adnexal Reporting and Data System (O-RADS):
- Simple cysts in postmenopausal women have only about 1.5% risk of malignancy 1
- The presence of septations increases the risk, placing the lesion in a higher risk category
- A 2 cm septated cyst in a postmenopausal woman would typically fall into O-RADS 3 category (1-<10% risk of malignancy) 1
Evidence Supporting Risk Assessment
The O-RADS US risk stratification system is based on extensive research and expert consensus. Key findings include:
- A meta-analysis by Parazzini et al. found that surgically removed unilocular cysts in postmenopausal women had approximately 1.5% risk of malignancy (7 of 469) 1
- Simple cysts (anechoic, thin-walled, no internal elements) have the lowest risk
- Adding septations increases the risk, moving the classification from O-RADS 2 to O-RADS 3
Management Implications
For a 2 cm septated ovarian cyst in a postmenopausal woman:
- Referral to gynecology is recommended due to the 1-10% risk of malignancy
- CA-125 testing should be considered as part of the evaluation
- Follow-up imaging is typically recommended in 3-6 months to assess for stability or change
Important Caveats
- The presence of other concerning features (solid components, irregular walls, ascites) would increase the risk and potentially change management
- Cysts that increase in size during follow-up warrant more aggressive evaluation
- Even small cysts with concerning features can harbor malignancy and should not be dismissed based on size alone
In summary, while most 2 cm septated ovarian cysts in postmenopausal women are benign, the risk of malignancy is approximately 1-10%, warranting appropriate gynecologic referral and follow-up.