What are the chances a second multiloculated (multiple compartments) septated (divided by walls) ovarian cyst in a postmenopausal woman is the same type as the first one if they appear similar on ultrasound?

Risk Assessment of Second Multiloculated Septated Ovarian Cyst in Postmenopausal Women

In a postmenopausal woman with a second multiloculated septated ovarian cyst that appears similar to a previously stable cyst on ultrasound, there is a high likelihood (>90%) that it represents the same benign pathology, but further evaluation is necessary as septated cysts in postmenopausal women carry a higher risk of malignancy compared to simple cysts. 1

Risk Assessment Based on Cyst Characteristics

• Multiloculated septated ovarian cysts in postmenopausal women require careful evaluation as they fall into a higher risk category than simple cysts 1
• According to the O-RADS US risk stratification system, septated cysts without solid components in postmenopausal women should be considered for further evaluation by a US specialist, gynecologist, or MRI 1
• While hemorrhagic cysts should not typically occur in postmenopausal women, other types of septated cysts like dermoid cysts or endometriomas can occur and may have similar appearances on follow-up imaging 1
• The risk of malignancy in septated cystic ovarian tumors without solid areas or papillary projections is relatively low, with studies showing minimal risk over long-term follow-up 2

Management Algorithm for Septated Ovarian Cysts in Postmenopausal Women

1. Initial Assessment:

   • Evaluate cyst size, internal architecture, and compare with previous imaging 1
   • Note any changes in morphology, size, or vascularity compared to the previous stable cyst 1

2. Risk Stratification:

   • If the cyst is <10 cm, multiloculated with thin septations, and without solid components or papillary projections, it likely represents the same pathology as the previous cyst 2
   • If the cyst shows new solid components, irregular septations, or increased vascularity, the risk of malignancy increases significantly 1

3. Management Based on O-RADS Classification:

   • Multiloculated septated cysts without solid components typically fall into O-RADS 3 (1-10% risk of malignancy) 1
   • Referral to a gynecologist or US specialist is recommended for further evaluation 1
   • MRI should be considered for better characterization of the cyst 1

Evidence for Stability vs. Change

• Studies show that 43.91% of simple cysts in postmenopausal women persist unchanged over follow-up periods, suggesting that stability over time is common for benign lesions 3
• In a study of 2870 septated cystic ovarian tumors followed over time, 61.2% persisted without resolution, with only one case developing malignancy after 3.2 years 2
• The appearance of a second similar-looking septated cyst after stability of the first one for a year suggests a recurrent benign process rather than malignant transformation 3, 2

Important Risk Factors to Consider

• Changes in morphology or developing vascular components within the lesion significantly increase the risk of malignancy 1
• The risk of malignant transformation is higher in certain types of cysts in postmenopausal women, particularly endometriomas (which can transform to clear cell and endometrioid carcinomas) 1
• Cyst size >10 cm increases risk and warrants gynecologic consultation regardless of other features 1

Follow-up Recommendations

• For multiloculated septated cysts <10 cm without solid components that appear similar to previous stable cysts:
  • Consider annual US follow-up when not surgically excised 1
  • Monitor for changes in morphology, size, or vascularity 1
• For cysts with changing morphology or developing vascular components:
  • Direct referral for MRI is recommended 1
  • Gynecologic oncology consultation should be considered 1

Common Pitfalls to Avoid

• Assuming all septated cysts in postmenopausal women require immediate surgical intervention - many can be safely monitored 4, 3
• Failing to recognize that septated cysts without solid components have a lower risk of malignancy than those with solid components or papillary projections 2
• Not comparing current imaging with previous studies to detect subtle changes that might indicate malignant transformation 1