Management of Mild Thyromegaly with Multiple Colloid Nodules Using TI-RADS
For patients with mild thyromegaly and multiple colloid nodules, apply TI-RADS classification to each nodule individually based on ultrasound features, then follow size-based thresholds for FNA or surveillance according to the risk category assigned. Colloid nodules typically present with benign sonographic features (smooth margins, isoechoic or hyperechoic appearance, comet-tail artifacts) that usually classify as TI-RADS 1-2, requiring no FNA regardless of size 1.
Risk Stratification Approach
Step 1: Classify Each Nodule by TI-RADS Category
Evaluate all nodules ≥1 cm using high-resolution ultrasound to assess five key sonographic features: composition, echogenicity, shape, margins, and echogenic foci 1, 2.
Colloid nodules characteristically demonstrate benign features including smooth regular margins with thin halo, no microcalcifications, isoechoic or hyperechoic appearance, and often comet-tail artifacts from colloid material 1.
Most colloid nodules will classify as TI-RADS 1 (benign) or TI-RADS 2 (not suspicious), which require no FNA at any size 1, 3.
Step 2: Apply Size-Based Management Thresholds
TI-RADS 1-2 nodules: No FNA required regardless of size, as these represent benign patterns with extremely low malignancy risk 1, 3.
TI-RADS 3 nodules (mildly suspicious): Follow-up ultrasound if >15mm, FNA if >25mm 1. These nodules have low malignancy risk but warrant surveillance if larger.
TI-RADS 4 nodules (moderately suspicious): Follow-up if >10mm, FNA if >15mm 1, 4. The combination of intermediate-risk features necessitates tissue diagnosis at smaller sizes.
TI-RADS 5 nodules (highly suspicious): Follow-up if >5mm, FNA if >10mm 1, 5. High-risk sonographic patterns require aggressive evaluation even when small.
Critical Decision Points for Multiple Nodules
Prioritization Strategy
When multiple nodules are present, prioritize the largest nodule with the highest TI-RADS category for initial evaluation, as larger size (≥3 cm) carries 3-times greater malignancy risk 1.
Do not perform FNA on nodules <10mm unless they demonstrate high-risk features (TI-RADS 5 with suspicious lymphadenopathy, subcapsular location, or history of head/neck radiation) 1, 3.
FNA should be performed for any nodule >1 cm with suspicious ultrasonographic features including hypoechogenicity, microcalcifications, irregular borders, or abnormal blood flow 1.
Common Clinical Scenarios and Pitfalls
The "Small Nodule" Dilemma
Current guidelines create management challenges for nodules <1 cm, as TI-RADS does not recommend FNA for most nodules below this threshold, yet performing FNA may yield suspicious results without definitive cancer subtyping 6.
For nodules 5-10mm classified as TI-RADS 4-5, surveillance is generally recommended rather than immediate FNA, unless additional high-risk clinical features are present (family history of thyroid cancer, prior radiation exposure, suspicious cervical lymphadenopathy) 1.
The decision-making becomes complex when a 9mm nodule is classified as high-risk by TI-RADS, as guidelines suggest follow-up instead of FNA, yet performing FNA may reveal suspicious cytology without ability to definitively stage the lesion preoperatively 6.
Avoiding Overdiagnosis
Colloid nodules in the setting of multinodular goiter are typically benign hyperplastic/adenomatoid nodules, especially when they demonstrate smooth margins, isoechoic appearance, and lack microcalcifications 1.
The risk of malignancy in nodules with benign sonographic features (TI-RADS 1-2) is approximately 1-3%, making routine FNA unnecessary and potentially leading to overdiagnosis of clinically insignificant cancers 1.
Avoid performing FNA on nodules <1 cm without high-risk features, as this leads to overdiagnosis and overtreatment of clinically insignificant cancers 1, 3.
Follow-Up Protocol
Surveillance Strategy
For TI-RADS 2 nodules (typical colloid nodules), no routine follow-up is required 1, 3.
For TI-RADS 3 nodules >15mm that do not meet FNA criteria, perform ultrasound surveillance at 12-month intervals initially 1.
Do not rely on thyroid function tests (TSH, T3, T4) for malignancy assessment, as most thyroid cancers present with normal thyroid function 1.
When to Reconsider FNA
If nodules demonstrate interval growth >20% in two dimensions with minimum 2mm increase in solid component, reconsider FNA even if below initial size thresholds 3.
If new suspicious features develop during surveillance (microcalcifications, irregular margins, increased vascularity), reclassify the nodule and apply appropriate FNA thresholds 1, 2.
Special Considerations
Symptomatic nodules causing pain, discomfort, or compressive symptoms warrant specialist referral regardless of TI-RADS classification, as these may require intervention even if benign 7.
The presence of multiple nodules does not increase individual nodule malignancy risk; each nodule should be evaluated independently based on its sonographic features 3, 4.
FNA remains the most accurate and cost-effective method for preoperative diagnosis of thyroid malignancy when indicated, with high sensitivity for detecting papillary thyroid carcinoma 1, 3.