What are the next steps in managing a patient with asymmetric thyroid lobes and bilateral solid nodules of worrisome appearance on ultrasound?

Management of Thyroid Nodules with Worrisome Ultrasound Features

Fine-needle aspiration biopsy (FNAB) should be performed immediately for all the thyroid nodules identified in this patient, as they demonstrate worrisome features (TR3) on ultrasound. 1

Assessment of Current Ultrasound Findings

The ultrasound reveals:

• Asymmetric thyroid lobes with enlarged left lobe (5.35 x 3.65 x 2.93 cm)
• Right lobe within normal limits (3.90 x 1.73 x 1.02 cm)
• Two adjacent solid isoechoic nodules with hypoechoic halo and internal vascularity in the right lobe (1.33 x 0.93 cm and 0.59 x 0.42 cm)
• Large similar nodule occupying most of the left lobe (3.55 x 2.06 cm)
• All nodules classified as TR3 (moderately suspicious)

Immediate Management Steps

1. FNAB of all nodules

   • FNAB is the gold standard for diagnosis of thyroid nodules 1
   • All nodules should undergo FNAB as they are classified as TR3 (moderately suspicious) 2
   • The largest nodule in the left lobe (3.55 x 2.06 cm) should be prioritized due to its size and location 1
   • The right lobe nodules should also be sampled, particularly the larger one (1.33 x 0.93 cm) 2

2. Laboratory Testing

   • Measure serum TSH levels before FNA to assess thyroid function 1
   • Complete blood count, coagulation profile, and blood biochemistry analysis should be performed 1

Interpretation of FNAB Results

FNAB results will be classified according to the Bethesda System for Reporting Thyroid Cytopathology 2:

• Nondiagnostic (Thy1)
• Benign (Thy2)
• Indeterminate (Thy3)
• Suspicious for malignancy (Thy4)
• Malignant (Thy5)

Management Based on FNAB Results

If Benign (Thy2):

• Regular ultrasound monitoring to assess volume changes 1
• Initial follow-up at 1 month, then at 3,6, and 12 months during the first year 1
• Annual follow-up thereafter 1
• Consider thermal ablation for nodules causing compression symptoms or cosmetic concerns 2

If Indeterminate (Thy3):

• Consider molecular testing to better stratify risk 3
• Consider surgical management (hemithyroidectomy) due to size of nodules 1

If Suspicious/Malignant (Thy4/Thy5):

• Surgical management is the treatment of choice 1
• Total thyroidectomy for bilateral suspicious nodules 1
• Hemithyroidectomy may be appropriate for well-differentiated thyroid cancer confined to one lobe 1

Important Considerations

• Multiple nodules: When multiple nodules are present, management should be guided by the most suspicious nodule 2
• Nodule size: The large size of the left lobe nodule (3.55 x 2.06 cm) increases concern and warrants thorough evaluation 4
• Ultrasound features: Solid composition, hypoechoic halo, and internal vascularity are features that increase suspicion for malignancy 1

Common Pitfalls to Avoid

1. Delaying FNAB: Do not delay FNAB for nodules with suspicious features regardless of size 1
2. Starting medication without indication: Avoid prescribing levothyroxine or other medications without clear indication based on thyroid function tests 1
3. Inadequate follow-up: Ensure systematic monitoring of nodules if initial evaluation is benign 1
4. Incomplete evaluation: Always evaluate cervical lymph nodes when thyroid nodules are found 2

Long-term Monitoring

If initial evaluation is benign:

• Continue regular ultrasound monitoring
• Assess for changes in size, echogenicity, or vascularity
• Re-evaluate if nodules demonstrate growth or develop suspicious features
• Consider thermal ablation for nodules ≥2 cm that are growing gradually or causing symptoms 2

By following this structured approach, you can ensure appropriate evaluation and management of these thyroid nodules with worrisome ultrasound features, minimizing the risk of missing a clinically significant malignancy while avoiding unnecessary interventions.