What is the appropriate management for a postmenopausal woman presenting with an adnexal mass?

Management of Adnexal Mass in Postmenopausal Women

Begin with transvaginal ultrasound combined with transabdominal ultrasound and color Doppler as your essential first-line imaging, then stratify management based on ultrasound morphology: simple cysts <3 cm require no follow-up, complex masses 1-6 cm without solid components can be followed with serial ultrasound at 6-7 months, indeterminate masses require MRI pelvis with IV contrast for further characterization, and suspicious masses warrant referral to a gynecologic oncologist. 1, 2, 3

Initial Diagnostic Workup

Clinical Assessment

• Evaluate for symptoms that persist daily for more than two weeks: pelvic/abdominal pain, urinary urgency/frequency, increased abdominal size/bloating, difficulty eating, and weight loss—these vague symptoms are present in up to 93% of ovarian cancer patients 4, 5
• These symptoms warrant further evaluation even if they fail to respond to appropriate therapy 5

First-Line Imaging

• Perform comprehensive ultrasound evaluation including transvaginal, transabdominal, and color/power Doppler components 1, 3
• Transvaginal ultrasound achieves >90% sensitivity for detecting adnexal pathology and establishes a benign diagnosis in 100% of postmenopausal women when a simple cyst is identified 1, 3
• Color Doppler is critical to assess vascularity of solid components and differentiate true solid tissue from debris 3, 6
• Ensure the ultrasound report includes: size, laterality, origin, septal thickness, presence of excrescences/solid components, vascular flow patterns, and ascites 4

Risk Stratification Based on Ultrasound Features

Simple Cysts (Benign)

• Simple cysts <3 cm require no follow-up due to extremely low malignancy risk of 0.3-0.4% and acute complication risk of 0.2-0.4% 2, 6
• Simple cysts are present in 17-24% of postmenopausal women and establish a benign process in 100% of cases 1, 6
• Natural history shows 53% disappear completely, 28% remain stable, and only small percentages change in size 1, 6
• Simple cysts >3 cm warrant follow-up ultrasound in 3-6 months 3

Complex Masses (Low-Risk)

• Complex masses 1-6 cm with only septations and no solid components carry only 1.3% malignancy risk 1, 2
• All epithelial cancers and borderline tumors in this category demonstrate growth by 7 months of observation 1, 2
• Follow with serial ultrasound at 6-7 months to assess for growth 2
• Solid hypoechoic masses with smooth margins, acoustic shadowing, and minimal Doppler flow (characteristic of thecoma-fibroma tumors) can be followed conservatively with 2% malignancy risk at 3 years if IOTA color score is 1-2 1, 2

Indeterminate Masses

• Masses that cannot be definitively classified as benign or malignant carry 3.6-10.7% malignancy risk depending on classification system used 1, 2
• MRI pelvis with and without IV contrast is the problem-solving modality of choice for indeterminate masses 1, 3
• Contrast-enhanced MRI performs superiorly to both ultrasound and non-contrast MRI by confirming presence and enhancement patterns of solid tissue 1, 3
• Enhancement curve characteristics drive malignancy risk: rapid enhancement greater than myometrium (type 3) is found only in invasive malignancies with 67% sensitivity, while slow low-level enhancement (type 1) indicates benign tumors with 70% sensitivity and 89% specificity 1

Suspicious Masses (High-Risk)

• Features worrisome for malignancy include: solid components with irregular contour (93% positive predictive value), >4 papillary structures, solid tissue with increased color/spectral Doppler flow, thick septations >2-3 mm, bilaterality, and ascites 1, 5
• Solid components with blood flow have 32% frequency of malignancy overall and up to 50% in women >60 years of age 1
• Refer immediately to gynecologic oncologist for surgical planning—this is the second most important prognostic factor after stage, yet only 33% of women with ovarian cancer receive appropriate subspecialty referral 3, 4

Management Algorithm by Mass Size

Masses <5 cm

• Only 1 of 32 masses <5 cm was malignant in a large series 7
• If simple or minimally complex with normal CA-125, follow with repeat ultrasound at 3-6 months 8
• If complex with normal CA-125, repeat ultrasound and CA-125 in 4 weeks 8

Masses 5-10 cm

• 6 of 55 masses in this size range were malignant (including borderline tumors) 7
• Requires more aggressive evaluation with MRI if indeterminate on ultrasound 1

Masses >10 cm

• 40 of 63 masses >10 cm were malignant 7
• All masses >10 cm warrant referral regardless of ultrasound appearance 5

Role of Tumor Markers

• Do not rely on CA-125 alone—it performs worse than ultrasound for distinguishing benign from malignant lesions 1, 3, 6
• CA-125 may be low with borderline and low-grade malignancies 1, 6
• CA-125 improves specificity only for masses already suspected malignant on ultrasound 1
• When combined with Doppler showing resistive index <0.5 and CA-125 cutoff of 65 U/mL (not the standard 35 U/mL), specificity reaches 100% 1, 3

Imaging Modalities to Avoid

• CT pelvis is not useful for characterization of adnexal masses and should not be obtained for this purpose 1, 3
• CT is reserved only for staging evaluation once malignancy is suspected, specifically for identifying other sites of disease and lymph node metastases 1, 3
• FDG-PET/CT is useful for staging ovarian cancer but not for initial characterization 1

Critical Pitfalls to Avoid

• Do not assume all postmenopausal adnexal masses are malignant—even in this population, the majority are benign, and simple/minimally complex cysts have very low malignancy rates 1, 2, 9
• Do not mistake pedunculated fibroids for ovarian masses—these are the most common solid adnexal masses in postmenopausal women (20-30%), so always identify normal ovaries separately and trace blood supply from uterine vessels 2, 6
• Do not skip color Doppler evaluation—it is essential for identifying vascularity patterns and differentiating solid tissue from debris 3, 6
• Do not over-surveil 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
• Do not perform unnecessary surgery on benign-appearing lesions—surgical exploration carries 2-15% complication rates, and accurate preoperative characterization prevents unnecessary intervention 3
• Do not delay referral for suspicious masses—any mass persisting longer than 12 weeks, evidence of metastatic disease, ascites, or complex features warrants gynecologic oncology consultation 5