What is the management approach for an adnexal (adnexal) mass?

Management of Adnexal Mass

Transvaginal ultrasound combined with transabdominal ultrasound and color Doppler is the essential first-line imaging modality for all patients presenting with a clinically suspected adnexal mass, regardless of menopausal status. 1

Initial Imaging Approach

• Perform comprehensive ultrasound evaluation including transvaginal, transabdominal, and color/power Doppler components as complementary procedures 1
• Transvaginal ultrasound achieves >90% sensitivity for detecting adnexal pathology and should be combined with transabdominal approach for optimal visualization, especially for larger masses 1, 2
• Color Doppler evaluation is critical to assess vascularity of solid components and confirm mass origin through identification of "bridging vessel sign" 1
• The bladder should be full during transabdominal scanning to provide optimal acoustic window 1

Risk Stratification Based on Ultrasound Features

After initial ultrasound, categorize masses into three groups:

Benign Masses

• Simple cysts (unilocular, no internal echoes, thin walls, no solid components, no vascularity) establish benign diagnosis in 98.7% of premenopausal and 100% of postmenopausal women 1
• Specific benign diagnoses can be made for endometriomas (low-level internal echoes, mural echogenic foci), dermoids (echogenic attenuating component), and hemorrhagic cysts (spiderweb appearance with peripheral vascularity) 1

Indeterminate Masses

• Masses with features that cannot definitively classify as benign or malignant carry only 3.6% to 10.7% malignancy risk 1
• Use standardized classification systems (O-RADS, IOTA simple rules, or SRU consensus criteria) to improve risk stratification 1
• O-RADS demonstrates 96.8% sensitivity and 92.8% specificity for malignancy detection 1

Suspicious Masses

• Solid components with irregular contour carry 93% positive predictive value for malignancy 1
• Lesions with >4 papillary structures or solid tissue with increased Doppler flow indicate 29-50% malignancy risk 1
• Frequency of malignancy in solid components with blood flow reaches 32% overall and 50% in women >60 years 1

Management Algorithm by Mass Category

For Benign-Appearing Masses:

Premenopausal patients:

• Simple cysts <5 cm require no follow-up 3
• Larger simple cysts or specific benign masses (endometriomas, dermoids) can be followed with serial ultrasound at 8-12 week intervals 1

Postmenopausal patients:

• Simple cysts <3 cm require no follow-up due to extremely low malignancy risk (0.3-0.4%) 2, 3
• Simple cysts >3 cm warrant follow-up ultrasound in 3-6 months 2
• Natural history shows 53% of postmenopausal simple cysts disappear completely, 28% remain stable 1, 2

For Indeterminate Masses:

Next step: MRI pelvis with and without IV contrast 1

• MRI is the problem-solving modality of choice when ultrasound findings are indeterminate 1
• Contrast-enhanced MRI achieves superior performance over ultrasound and non-contrast MRI by confirming presence and enhancement patterns of solid tissue 1
• MRI sensitivity and specificity reach 85-100% for malignancy detection 1
• Critical caveat: Non-contrast MRI has decreased utility, with ADNEX MR system specificity falling below 90% without dynamic contrast enhancement 1

Alternative approach for well-visualized indeterminate masses:

• Serial ultrasound follow-up at 8-12 week intervals is acceptable for masses that remain stable and well-seen on ultrasound 1
• In postmenopausal women with complex masses 1-6 cm, malignancy risk is only 1.3% if no growth occurs by 7 months 1

For Suspicious Masses:

Immediate actions required:

• Refer to gynecologic oncologist for surgical planning 4, 5, 6
• Obtain CT abdomen/pelvis with IV contrast for staging evaluation 2
• Do not use CT for mass characterization—CT has poor soft-tissue discrimination and limited ability to characterize adnexal masses 1
• FDG-PET/CT is useful for identifying other sites of disease and detecting lymph node metastasis in confirmed malignancy 1

Role of Tumor Markers

• CA-125 alone should not be used as a standalone test to distinguish benign from malignant masses 1
• CA-125 performs worse than ultrasound in differentiating benign from malignant lesions 1
• When combined with Doppler showing resistive index <0.5 and CA-125 cutoff of 65 U/mL (not 35 U/mL), specificity reaches 100%, but only for masses already suspected malignant on ultrasound 1
• CA-125 may be low in borderline and low-grade malignant tumors, limiting its utility 1

Special Populations

Pregnant patients:

• Use same ultrasound approach (transvaginal, transabdominal, Doppler) as initial imaging 1
• For indeterminate masses, MRI pelvis without contrast is appropriate since gadolinium is not recommended in pregnancy 1
• Non-contrast MRI maintains 96.4% accuracy for diagnosing benign lesions despite reduced specificity for malignancy 1
• Diffusion-weighted imaging helps distinguish decidualized endometriomas from malignancy 1

Critical Pitfalls to Avoid

• Never obtain CT for initial characterization of adnexal masses—this wastes resources and exposes patients to radiation without diagnostic benefit 1
• Do not skip color Doppler evaluation—spectral Doppler parameters alone have overlapping features, but color Doppler identifies vascularity patterns critical for risk assessment 1
• Avoid over-surveillance of simple cysts—large studies show simple cysts carry 0-0.5 cases per 10,000 women 3-year cancer risk, equivalent to women with normal ovaries 3
• Recognize that surgical exploration of benign lesions carries 2-15% complication rates—accurate preoperative characterization prevents unnecessary surgery 1
• Ensure gynecologic oncologist involvement for suspicious masses—only 33% of women with eventual ovarian cancer diagnosis receive appropriate subspecialty referral, yet this is the second most important prognostic factor after stage 1