Management of TR2 Thyroid Nodules
For TR2 thyroid nodules, no fine-needle aspiration is required and no routine follow-up is necessary, as these represent benign-appearing cysts with an extremely low malignancy risk. 1
Understanding TR2 Classification
TR2 nodules are classified as "not suspicious" under the ACR TI-RADS system and carry a malignancy risk under 5%. 2 The current case demonstrates:
- Multiple bilateral cysts (Nodule 1: 0.5×0.3×0.2 cm right side; Nodule 2: 0.4×0.4×0.4 cm left side)
- No dominant lesion present
- No high-grade features identified
The institutional protocol correctly states that TR2 nodules require no FNA regardless of size. 1
Evidence-Based Management Strategy
No Biopsy Required
FNA is not indicated for TR2 nodules at any size threshold. 1 The guidelines are explicit that TR1 and TR2 categories do not warrant tissue sampling due to their benign sonographic characteristics. 2, 1
This represents a departure from older approaches that recommended FNA for nodules >1 cm. 2 The ACR TI-RADS system deliberately decreased the number of nodules requiring biopsy to reduce overdiagnosis and overtreatment of clinically insignificant lesions. 3
Follow-Up Recommendations
No routine surveillance imaging is recommended for TR2 nodules. 4 While some malignant nodules may not meet ACR TI-RADS criteria for FNA, the vast majority of these are either <1 cm or would be captured in higher-risk categories. 3
Exception: If a TR2 nodule grows to ≥2.5 cm, consider follow-up ultrasound, though this threshold remains controversial. 3 In the current case, both nodules are <0.5 cm, making this consideration irrelevant.
Clinical Context That Would Modify Management
The following high-risk features would warrant reconsideration of the TR2 classification and potentially lower the threshold for intervention:
- History of head and neck irradiation 1
- Family history of thyroid cancer (particularly medullary thyroid carcinoma or familial syndromes) 1
- Rapidly growing nodule despite benign appearance 1
- Suspicious cervical lymphadenopathy 1
- Compressive symptoms (dysphagia, voice changes, breathing difficulty) 4
None of these features are mentioned in the current case presentation.
What to Communicate to the Patient
Reassure the patient that these are benign cysts requiring no treatment or follow-up. 1 The palpable lump at the sternal notch has been adequately evaluated and explained by the imaging findings.
No thyroid function testing is needed unless the patient develops symptoms of thyroid dysfunction, as most thyroid cancers present with normal thyroid function. 4
Common Pitfalls to Avoid
- Do not perform FNA on small TR2 nodules simply because they are palpable—this leads to overdiagnosis. 1, 5
- Do not order routine surveillance ultrasounds for stable TR2 nodules, as this increases healthcare costs without improving outcomes. 4
- Do not proceed to radionuclide scanning in euthyroid patients, as this has no role in determining malignancy risk. 4
- Avoid using nodule size alone as an indication for FNA without considering sonographic risk features. 1, 3
Strength of Evidence
This recommendation is based on high-quality guideline evidence from the American College of Radiology TI-RADS system (2025), which represents the most current and widely adopted risk stratification approach for thyroid nodules. 1 The ACR TI-RADS explicitly addresses TR2 nodules and provides clear management algorithms that prioritize avoiding unnecessary procedures while maintaining patient safety. 1, 3
The 2025 guideline discussion acknowledges ongoing debates about small thyroid nodules but emphasizes that TR2 lesions specifically do not require intervention. 2