How should a thyroid nodule classified as TIRADS 2 be managed when there are no high‑risk clinical features?

Management of TIRADS 2 Thyroid Nodules

TIRADS 2 thyroid nodules are benign lesions that do not require fine-needle aspiration biopsy and should be managed with surveillance ultrasound only, unless compressive symptoms develop. 1

Definition and Malignancy Risk

• TIRADS 2 nodules represent benign thyroid lesions with a malignancy risk of essentially 0%, including spongiform nodules, purely cystic nodules, and nodules with comet-tail artifacts. 1, 2
• These nodules lack any suspicious ultrasound features such as microcalcifications, marked hypoechogenicity, irregular margins, or central hypervascularity. 1

Standard Management Protocol

Surveillance ultrasound is the only recommended intervention for TIRADS 2 nodules without high-risk clinical features. 1

• Perform initial follow-up ultrasound at 12 months to document stability. 3
• If the nodule remains stable in size and ultrasound characteristics, continue surveillance at 12–24 month intervals. 3
• Do not perform fine-needle aspiration biopsy on TIRADS 2 nodules, as this leads to overdiagnosis and overtreatment of benign lesions. 1, 3

Imaging Considerations

• Use high-resolution ultrasound exclusively for surveillance; do not order radionuclide scans, CT, or MRI for routine follow-up of benign-appearing thyroid nodules. 1
• Ultrasound provides superior resolution for nodule characterization compared to other imaging modalities and avoids unnecessary radiation exposure. 1
• Radionuclide scanning is not helpful in euthyroid patients for determining malignancy risk. 1, 4

When to Escalate Management

Proceed to fine-needle aspiration only if the nodule develops any of the following during surveillance: 1

• Compressive symptoms such as dysphagia, dyspnea, or voice changes
• Significant growth defined as ≥3 mm increase in any dimension 1
• Development of suspicious ultrasound features including microcalcifications, marked hypoechogenicity, irregular margins, or loss of peripheral halo 1
• Suspicious cervical lymphadenopathy on comprehensive neck ultrasound 1

Role of Thyroid Function Tests

• Do not rely on thyroid function tests (TSH, T3, T4) to evaluate malignancy risk, as most thyroid cancers present with normal thyroid function. 3
• Measure serum calcitonin only if atypical sonographic features arise during surveillance, because calcitonin testing offers higher sensitivity for detecting medullary thyroid carcinoma than repeat FNA alone. 1

High-Risk Clinical Features That Modify Management

Even for TIRADS 2 nodules, consider earlier or more frequent surveillance (not immediate FNA) if any of the following high-risk features are present: 1, 3

• History of head and neck irradiation
• Family history of thyroid cancer (particularly medullary carcinoma or familial syndromes)
• Age <15 years
• Rapidly growing nodule documented during follow-up

However, these clinical factors alone do not warrant FNA of a TIRADS 2 nodule unless suspicious ultrasound features develop. 1, 3

Critical Pitfalls to Avoid

• Do not perform systematic biopsy of nodules >1 cm without considering TIRADS classification, as size alone does not justify FNA for benign-appearing lesions. 3
• Do not confuse mild hypoechogenicity with marked hypoechogenicity; only the latter is a suspicious criterion that would reclassify the nodule to a higher TIRADS category. 3
• Do not override the TIRADS 2 classification based solely on nodule size; a 3 cm TIRADS 2 nodule still carries negligible malignancy risk and does not require FNA unless compressive symptoms are present. 1

Evidence Supporting Conservative Management

• The high-risk categories of ultrasound-based risk stratification systems display strong associations with malignant cytology, while low-risk classes (including TIRADS 2) are clearly associated with benign cytology. 5
• The diagnostic performance of ultrasound risk stratification has reached a level approaching that of fine-needle aspiration cytology, supporting the use of surveillance alone for low-risk nodules. 5
• Benign thyroid nodules confirmed by core needle biopsy after inconclusive FNA showed stable status during follow-up in 95.2% of cases, with no upgrade in imaging category or newly diagnosed malignancy. 6