What is the next step in managing a patient with bilateral thyroid solid nodules, decreased thyroid size, and a TI-RADS (Thyroid Imaging Reporting and Data System) classification of 3?

Management of TI-RADS 3 Bilateral Thyroid Nodules

For these bilateral thyroid nodules classified as TI-RADS 3, with the largest measuring 0.48 cm, no fine-needle aspiration is indicated and ultrasound surveillance at 12 months is the appropriate next step. 1, 2

Rationale for Surveillance Over Biopsy

• TI-RADS 3 nodules require a size threshold of >2.5 cm before FNA is recommended, and your nodules measure only 0.48 cm and 0.31 cm—well below this threshold 1
• The ACR TI-RADS classification specifically states that mildly suspicious nodules (TR3) should undergo FNA only when >2.5 cm, with follow-up recommended for nodules between 1.0-2.5 cm 1
• Nodules <1 cm without high-risk features are typically recommended for surveillance rather than immediate biopsy, as routine biopsy of subcentimeter nodules leads to overdiagnosis and overtreatment of clinically insignificant cancers 1, 2, 3

Surveillance Protocol for TI-RADS 3 Nodules

• Follow-up ultrasound should be performed at 1,3, and 5 years for TI-RADS 3 nodules that do not meet size criteria for FNA 1
• The initial 12-month follow-up recommended in your report aligns with standard TI-RADS 3 surveillance protocols 1
• During surveillance, monitor for interval growth, development of suspicious features (microcalcifications, irregular margins, marked hypoechogenicity), or increase in size that would trigger FNA 1, 4

Clinical Correlation Required

• Obtain thyroid function tests (TSH, free T4) to assess for underlying thyroid dysfunction, particularly given the decreased thyroid size and inhomogeneous texture suggesting possible chronic thyroiditis 1
• The decreased gland size with inhomogeneous texture raises concern for Hashimoto's thyroiditis, which can produce hyperplastic nodules that mimic suspicious features on ultrasound 5
• Assess for high-risk clinical factors that would lower the FNA threshold even for small nodules: history of head/neck irradiation, family history of thyroid cancer (especially medullary carcinoma or familial syndromes), age <15 years, rapidly growing nodule, or suspicious cervical lymphadenopathy 1

When to Escalate to FNA Despite Small Size

• If any high-risk clinical factors are present (radiation history, family history of thyroid cancer, suspicious lymph nodes), consider FNA even for nodules <1 cm 1
• If the nodule is subcapsular in location, this represents a high-risk feature that may warrant earlier intervention 1
• If interval growth is documented on follow-up ultrasound, particularly if the nodule reaches 1.0 cm or develops additional suspicious features 1, 6

Important Caveats

• The ACR TI-RADS system has 98.8% specificity for identifying benign nodules, meaning it safely avoids unnecessary biopsies in the vast majority of cases 7
• However, approximately 1.2% of nodules classified as TR2 or TR3 <2.5 cm may harbor malignancy, though most are clinically insignificant micropapillary carcinomas 7
• Fibrosis within benign nodules is the most common histopathological feature causing false-positive suspicious ultrasound findings in TI-RADS 4-5 classifications, and this is particularly relevant in the setting of chronic thyroiditis 5
• Studies show that adjusting size thresholds downward to catch more malignancies would result in a substantial increase in benign nodules undergoing unnecessary follow-up and biopsy 6

What NOT to Do

• Do not perform FNA on these nodules based solely on their solid composition or isoechoic appearance—size criteria must be met for TI-RADS 3 lesions 1, 2
• Do not rely on thyroid function tests alone to assess malignancy risk, as most thyroid cancers present with normal thyroid function 1
• Avoid ordering radionuclide scanning in euthyroid patients, as it is not helpful in determining malignancy and ultrasound is the only appropriate initial imaging modality 1