What is the management approach for a 75-year-old asymptomatic female with a 20mm adnexal (adnexal refers to structures around the uterus, such as the ovaries, fallopian tubes, and surrounding tissues) lesion found on computed tomography (CT) scan?

Management of a 20mm Adnexal Lesion in a 75-Year-Old Asymptomatic Female

For a 75-year-old asymptomatic female with a 20mm adnexal lesion found on CT scan, transvaginal ultrasound is the recommended next step for further characterization, as most adnexal lesions in postmenopausal women are benign and can be managed conservatively with appropriate imaging follow-up. 1

Initial Evaluation

• Transvaginal ultrasound is the essential first-line imaging modality for characterizing adnexal lesions, with sensitivity >90% for detecting adnexal pathology 1
• Combined transabdominal and transvaginal ultrasound approach provides optimal evaluation, allowing detailed assessment of lesion characteristics 1
• Color or power Doppler should be included in the ultrasound examination to evaluate for vascularity within any solid components, which helps differentiate benign from malignant masses 1

Interpretation of Findings

If Simple Cyst Features:

• Simple cysts in postmenopausal women are common (17-24% frequency) and typically benign 1, 2
• A simple cyst is characterized by:
  • Unilocular structure with no internal echoes
  • Thin walls with no solid components
  • No septations or papillary projections
  • No vascularity on color Doppler imaging 3
• Simple cysts <3cm in postmenopausal women require no follow-up due to extremely low risk of malignancy (0.3-0.4%) 2, 3

If Indeterminate Features:

• Indeterminate masses in postmenopausal women are generally benign but require further evaluation 1
• Features suggesting indeterminacy include:
  • Multiple septations
  • Solid components
  • Papillary projections
  • Mural nodules 1
• MRI with IV contrast is recommended as the next step for indeterminate lesions to improve characterization 1

If Suspicious Features:

• Features suggesting malignancy include:
  • Solid components
  • Thick septations (>2-3mm)
  • Papillary projections
  • Enhancing mural nodules
  • Significant vascularity on Doppler 4, 1
• If highly suspicious for malignancy, refer to gynecologic oncologist and proceed with CT abdomen/pelvis with IV contrast for staging 1

Management Algorithm

1. For simple cyst <3cm:

   • No follow-up required 2, 3
   • Risk of malignancy is extremely low (0.3-0.4%)
   • Risk of acute complications (torsion/rupture) is similarly low (0.2-0.4%) 3

2. For simple cyst >3cm:

   • Follow-up ultrasound in 3-6 months to ensure stability 1, 3
   • If stable for 1 year, no further follow-up needed 1

3. For indeterminate lesion:

   • MRI pelvis with and without IV contrast for further characterization 1, 5
   • If benign features on MRI, follow-up with ultrasound in 3-6 months 1
   • If suspicious features on MRI, refer to gynecologic oncologist 6

4. For suspicious lesion:

   • Immediate referral to gynecologic oncologist 4, 6
   • CT abdomen/pelvis with IV contrast for staging 1
   • Consider FDG-PET/CT if metastatic disease is suspected 1

Common Pitfalls to Avoid

• Mistaking pedunculated fibroids for ovarian masses - always look for normal ovaries and identify blood supply from uterine vessels 2
• Relying solely on CT for adnexal mass characterization - CT has suboptimal soft tissue delineation in the adnexal region 1
• Failing to use color Doppler in evaluation - essential for differentiating true solid components from solid-appearing debris 2
• Unnecessary surgery for benign lesions - surgical exploration of benign lesions has reported complication rates of 2-15% 1
• Over-reliance on CA-125 - this marker performs worse than ultrasound in distinguishing benign from malignant lesions 2

Natural History of Postmenopausal Simple Adnexal Cysts

• 53% disappear completely
• 28% remain constant in size
• 11% enlarge by 3mm
• 3% decrease in size by 3mm
• 6% both increase and decrease in size on repeated examinations 1

Remember that pedunculated leiomyomas (fibroids) are the most common solid adnexal masses in postmenopausal women, present in approximately 20-30% of this population 2, 1.