What is the recommended management for a patient with a multinodular thyroid gland and bilateral solid nodules, including one with worrisome appearance and internal vascularity?

Management of Multinodular Thyroid Gland with Worrisome Nodules

Fine-needle aspiration biopsy (FNAB) is strongly recommended for the worrisome nodules in the left lobe classified as TR4, as this is the gold standard for diagnosis of thyroid nodules with suspicious features. 1

Initial Assessment and Risk Stratification

The ultrasound findings reveal:

• Multiple bilateral solid nodules with heterogeneous echotexture
• Left lobe nodules of concern:
  • 0.86 x 0.78 cm isoechoic nodule with hypoechoic halo and internal vascularity
  • 0.52 x 0.44 cm hypoechoic nodule with internal vascularity
  • 0.93 x 0.37 cm echogenic nodule
• Right lobe nodules:
  • Two solid hypoechoic nodules (0.69 x 0.30 cm and 0.59 x 0.51 cm)
• Calcified focus in left lobe (0.62 x 0.54 cm)

The nodules classified as TR4 (moderately suspicious) require further evaluation due to their worrisome features, particularly the internal vascularity and hypoechoic appearance 1.

Diagnostic Approach

1. Fine-needle aspiration biopsy (FNAB):

   • FNAB should be performed on the TR4 nodules in the left lobe, particularly those with internal vascularity 2, 1
   • FNAB is the preferred method for pathological diagnosis of thyroid nodules and has high sensitivity and specificity 2
   • The presence of suspicious characteristics on ultrasound (hypoechogenicity, internal vascularity) warrants FNAB regardless of nodule size 1

2. Laboratory evaluation:

   • Thyroid function tests (TSH) should be performed to assess functional status 1
   • Consider calcitonin measurement if there is suspicion for medullary thyroid carcinoma 1

Management Algorithm

1. For nodules with benign FNAB results:

   • If nodules have three or more suspicious US features (categories 4c and 5), consider repeat FNAB due to higher malignancy risk (9.8-22.2%) 3
   • For nodules with fewer suspicious features, ultrasound surveillance is appropriate 1

2. For nodules with malignant or suspicious FNAB results:

   • Surgical management (total or partial thyroidectomy) based on extent of disease 1
   • Evaluate cervical lymph nodes for potential metastasis 2

3. For nodules with indeterminate FNAB results:

   • Consider molecular testing to further stratify risk 1
   • Core needle biopsy (CNB) may be considered for FNAB-undiagnosed thyroid nodules 2

Follow-up Protocol

For nodules under surveillance:

• Initial follow-up ultrasound at 1 month
• Subsequent follow-up at 3,6, and 12 months during the first year
• Annual follow-up thereafter 1

Special Considerations

1. Multinodular goiter management:

   • Even in multinodular goiters, individual nodules with suspicious features require FNAB 4
   • The presence of multiple nodules does not reduce the risk of malignancy in suspicious nodules 4

2. Small nodules (<1 cm):

   • Small nodules with suspicious features still carry significant malignancy risk
   • For nodules ≤10 mm with categories 4c and 5 features, malignancy risks are 12.6% and 22.6% respectively 3

Avoiding Common Pitfalls

1. Do not assume benign nature without cytologic evaluation of suspicious nodules 1
2. Do not delay diagnosis of nodules with worrisome ultrasound features 1
3. Do not perform surgery without cytological confirmation of malignancy or high suspicion 1
4. Do not overlook the importance of ultrasound characteristics in risk stratification, as they are more reliable than nodule size alone in predicting malignancy 2, 5

The management of this multinodular thyroid gland requires careful evaluation of the worrisome nodules through FNAB, with subsequent management guided by cytology results and ultrasound characteristics.