What is the recommended management for a patient with bilateral solid thyroid nodules, including two nodules with worrisome appearance on ultrasound?

Management of Bilateral Thyroid Nodules with Worrisome Ultrasound Features

Fine-needle aspiration biopsy (FNAB) should be performed for the two nodules in the left lobe classified as TR4 (worrisome appearance) to confirm the pathological diagnosis. 1

Evaluation of Thyroid Nodules

Initial Assessment

• The ultrasound reveals bilateral solid thyroid nodules with two nodules in the left lobe classified as TR4 (worrisome appearance)
• The thyroid gland appears normal in size with symmetric lobes
• Five nodules are identified:
  • Right lobe: Two solid hypoechoic nodules (0.69 × 0.30 cm and 0.59 × 0.51 cm)
  • Left lobe: Three nodules, including two with worrisome features (TR4)
    • Isoechoic with hypoechoic halo and internal vascularity (0.86 × 0.78 cm)
    • Hypoechoic with internal vascularity (0.52 × 0.44 cm)
    • Echogenic nodule (0.93 × 0.37 cm)

Diagnostic Steps

1. FNAB of suspicious nodules: All patients undergoing evaluation for thyroid nodules should have FNAB to confirm pathological diagnosis 1

   • Focus on the two TR4 nodules in the left lobe
   • FNAB is preferred over core needle biopsy (CNB) due to lower complication rates

2. Laboratory testing:

   • TSH measurement to assess thyroid function
   • Consider calcitonin testing if medullary thyroid carcinoma is suspected 1

3. Comprehensive neck ultrasound:

   • Evaluate for suspicious cervical lymph nodes
   • Assess for signs of extrathyroidal extension

Management Algorithm Based on FNAB Results

If FNAB Confirms Malignancy (Bethesda VI):

• Total thyroidectomy with bilateral central neck dissection (level VI) 1
• Consider therapeutic ipsilateral or bilateral modified neck dissection for clinically identifiable disease (levels II-V)
• Consider prophylactic ipsilateral modified neck dissection if there is high volume disease in the adjacent central neck

If FNAB Shows Indeterminate Cytology (Bethesda III or IV):

• Consider molecular testing to further stratify risk 2
• Options based on risk assessment:
  • Low risk: Active surveillance with repeat ultrasound in 6-12 months
  • Intermediate/high risk: Consider surgical intervention

If FNAB Shows Benign Results (Bethesda II):

• For nodules causing symptoms (compression, cosmetic concerns) or ≥2 cm with gradual growth:
  • Consider thermal ablation techniques (RFA, MWA, LA) 1
• For asymptomatic nodules <2 cm:
  • Surveillance with ultrasound at 6-12 month intervals

Important Considerations

Risk Factors for Malignancy

• Suspicious ultrasound features (already identified as TR4):
  • Internal vascularity
  • Hypoechoic appearance
  • Solid composition
• Clinical factors that increase risk:
  • History of head and neck irradiation
  • Family history of thyroid cancer
  • Age <15 or >70 years
  • Male gender

Potential Pitfalls

1. False-negative FNAB results: Even with a reassuring FNAB, worrisome clinical or ultrasound findings should not be ignored 1

2. Inadequate sampling: Ensure FNAB is performed by an experienced operator under ultrasound guidance to minimize non-diagnostic results

3. Multiple nodule management: When multiple nodules are present, focus diagnostic efforts on the most suspicious nodules based on ultrasound features rather than size alone 2

4. Overtreatment risk: Avoid aggressive management for micropapillary carcinomas (<1 cm) without high-risk features, as they generally have excellent prognosis 2

Follow-up Recommendations

• For nodules under surveillance:
  • Repeat ultrasound at appropriate intervals based on risk assessment
  • Monitor for changes in size, appearance, or development of new suspicious features
  • Consider repeat FNAB if growth or change in appearance occurs

By following this structured approach, the management of these bilateral thyroid nodules with worrisome features can be optimized to ensure appropriate diagnosis and treatment while minimizing unnecessary interventions.