What are the next steps in managing a patient with a multinodular thyroid gland and bilateral solid benign nodules?

Management of Multinodular Thyroid Gland with TR2 Nodules

For this multinodular thyroid gland with bilateral TR2 (benign-appearing) nodules, the appropriate next step is to obtain thyroid function tests (TSH, free T4) and proceed with clinical surveillance rather than fine-needle aspiration biopsy. 1

Immediate Diagnostic Steps

Thyroid Function Testing

• Measure serum TSH and free T4 to assess for hyperthyroidism or hypothyroidism, which commonly accompanies multinodular goiter 2, 3
• If TSH is suppressed, obtain a thyroid radionuclide scan with 99mTc to determine if any nodules are autonomously functioning ("hot"), which would indicate toxic multinodular goiter requiring different management 4, 3

Consider Serum Calcitonin Measurement

• Serum calcitonin should be measured as part of the diagnostic evaluation of thyroid nodules to screen for medullary thyroid cancer, which has higher sensitivity than FNA alone 5, 1
• This is particularly important given the bilateral multinodular presentation 5

FNA Biopsy Decision-Making

TR2 Classification Does NOT Warrant FNA

• TR2 nodules are classified as "not suspicious" with very low malignancy risk 1
• The largest nodules measure 0.77 cm (right) and 0.67 cm (left), both under the 1.0 cm threshold that typically triggers FNA consideration 5, 1
• FNA is recommended for nodules >1 cm, and for nodules <1 cm only if suspicious ultrasonographic features are present (hypoechogenicity, microcalcifications, irregular borders, abnormal blood flow) 5, 1
• Avoid performing FNA on nodules <1 cm without high-risk features, as this leads to overdiagnosis and overtreatment of clinically insignificant cancers 1

High-Risk Features That Would Change Management

FNA threshold should be lowered if any of these are present:

• History of head and neck irradiation 1
• Family history of thyroid cancer 1
• Suspicious cervical lymphadenopathy on ultrasound 1
• Rapid nodule growth on serial imaging 1

Surveillance Protocol

Initial Follow-Up Ultrasound Timing

• Perform repeat thyroid ultrasound in 12-24 months to assess for stability of nodule size and characteristics 1, 3
• The heterogeneous echotexture and increased vascularity noted warrant monitoring, even though these features alone do not mandate immediate FNA in TR2 nodules 2

Long-Term Monitoring

• If nodules remain stable in size and appearance, continue annual clinical examination with thyroid palpation 5
• Repeat ultrasound can be extended to every 2-3 years if nodules demonstrate stability over initial surveillance period 3
• Do not rely on thyroid function tests alone for malignancy assessment, as most thyroid cancers present with normal thyroid function 1

Clinical Correlation Requirements

Assess for Compressive Symptoms

• Evaluate for dysphagia, dyspnea, or voice changes that would indicate mass effect requiring intervention regardless of benign cytology 3
• The reported normal size and absence of concerning anatomic structure involvement is reassuring 3

Document Risk Factors

• Obtain detailed history of radiation exposure, family history of thyroid disease or cancer, and rate of nodule growth 1, 6
• These factors may influence surveillance intervals and threshold for intervention 6

When to Proceed to FNA Despite TR2 Classification

Perform FNA if any of the following develop:

• Nodule growth to ≥1.0 cm with development of suspicious features 5, 1
• New suspicious sonographic characteristics (microcalcifications, irregular margins, marked hypoechogenicity, taller-than-wide shape) 5, 1
• Development of suspicious cervical lymphadenopathy 1
• Clinical symptoms suggesting malignancy or rapid growth 3

Common Pitfalls to Avoid

• Do not perform FNA based solely on multinodular appearance or increased vascularity - these features are common in benign multinodular goiter and do not independently warrant biopsy in TR2 nodules 2, 4
• Do not assume all nodules in multinodular goiter are benign - malignancy risk is similar in solitary nodules versus multinodular goiter (approximately 7-15%), but TR2 classification already accounts for this 4, 3
• Do not neglect lateral neck ultrasound evaluation - assess for lymphadenopathy that could suggest occult malignancy 2
• The incidence of malignancy in benign-appearing nodules is approximately 2%, supporting surveillance over immediate intervention 7