What is the diagnostic workup for an adnexal mass in an elderly patient?

Workup for an Adnexal Mass in an Elderly Patient

Begin with transvaginal ultrasound combined with transabdominal ultrasound and color Doppler evaluation as the essential first-line diagnostic approach for any elderly patient with a suspected adnexal mass. 1, 2

Initial Imaging Strategy

• Transvaginal ultrasound with color Doppler is the cornerstone of evaluation, providing >90% sensitivity for detecting adnexal pathology and allowing detailed characterization of mass features. 2

• Transabdominal ultrasound must be performed concurrently to evaluate larger masses that may extend beyond the transvaginal field of view and to assess the upper abdomen for ascites or other findings. 1

• Color or power Doppler is mandatory, not optional, as it evaluates vascularity within solid components to differentiate malignancy from benign findings like clot or debris. 1

Key Ultrasound Features to Document

The ultrasound report must include specific characteristics to calculate malignancy risk:

• Size and laterality (unilateral vs bilateral). 3
• Presence and thickness of septations (thin vs thick irregular). 3
• Solid components with vascular flow on Doppler. 1
• Papillary projections or excrescences. 3
• Ascites or peritoneal nodules. 3

Risk Stratification Based on Ultrasound

Simple Cysts

• Simple cysts <3 cm require no follow-up due to extremely low malignancy risk (0.3-0.4%) in postmenopausal women. 2
• Simple cysts >3 cm warrant follow-up ultrasound in 3-6 months to ensure stability, though malignancy risk remains very low. 2
• Simple cysts are common (17-24% frequency) in elderly women and typically benign, characterized by unilocular structure, no internal echoes, thin walls, no septations, and no vascularity. 1, 2

Indeterminate Masses

• MRI pelvis with and without IV contrast is the next step for masses that remain indeterminate after ultrasound, as it provides superior soft tissue characterization. 1, 2
• MRI demonstrates sensitivity of 100% for malignancy and specificity of 94% for benignity when ultrasound is inconclusive. 1
• Contrast-enhanced MRI is significantly superior to noncontrast MRI for detecting enhancing solid components that indicate malignancy. 1

Suspicious Features Requiring Immediate Action

If ultrasound reveals any of these features, immediate referral to a gynecologic oncologist is indicated:

• Solid components with internal vascularity on Doppler. 4
• Thick irregular septations. 4
• Papillary projections or mural nodules. 4
• Ascites or peritoneal nodules. 4
• Bilateral masses. 3

Laboratory Evaluation

• CA-125 measurement should be obtained in postmenopausal women with an adnexal mass, as it assists in risk stratification when combined with ultrasound findings. 3, 5
• CA-125 alone cannot differentiate benign from malignant masses due to overlap in values, but elevated levels increase suspicion for malignancy in the appropriate clinical context. 5

When to Obtain CT Imaging

• CT is NOT useful for initial characterization of adnexal masses due to suboptimal soft tissue delineation compared to ultrasound and MRI. 1

• CT abdomen and pelvis with IV contrast is reserved for staging when malignancy is highly suspected or confirmed, not for initial diagnosis. 1, 4

• The exception: CT can diagnose dermoid cysts when macroscopic fat with calcification or Rokitansky nodule is visible. 1

Critical Pitfalls to Avoid

• Never biopsy a suspected adnexal mass before complete imaging characterization and oncology consultation, as this risks tumor spillage if malignant. 4

• Do not assume all calcified masses are benign—serous cystadenocarcinoma can calcify, requiring MRI for definitive characterization. 4

• Avoid ordering MRI after ultrasound for clearly benign simple cysts, as this delays care without improving outcomes and does not increase appropriate referral rates. 6

• Maintain higher suspicion for malignancy in elderly patients even with simple-appearing lesions, as ovarian cancer incidence increases with age. 4

Management Algorithm Summary

1. All elderly patients: Transvaginal + transabdominal ultrasound + color Doppler. 1, 2

2. Simple cyst <3 cm: No follow-up needed. 2

3. Simple cyst >3 cm: Repeat ultrasound in 3-6 months. 2

4. Indeterminate mass: MRI pelvis with and without IV contrast. 1, 2

5. Suspicious features: Immediate gynecologic oncology referral + CT abdomen/pelvis for staging. 1, 4

PET/CT has no role in initial evaluation or characterization of adnexal masses, as it cannot reliably differentiate benign from malignant lesions and has low uptake in certain ovarian cancer subtypes. 1