What is the management approach for a patient diagnosed with a nodular cystic goiter via fine-needle aspiration (FNA)?

Management of Nodular Cystic Goiter Diagnosed by FNA

For a nodular cystic goiter with benign FNA cytology (Bethesda II), clinical and ultrasound surveillance is the appropriate management rather than surgery, given the extremely low malignancy risk of 1-3%. 1, 2

Initial Diagnostic Confirmation

Ensure pathology review by an expert thyroid pathologist at your treating institution, as FNA interpretation requires specialized expertise and false-negative results occur in up to 11-33% of cases. 1 The Bethesda classification system categorizes benign results (nodular goiter, colloid goiter, hyperplastic/adenomatoid nodule) as Category II with 1-3% malignancy risk. 1, 2

Surveillance Protocol for Benign Nodules

Implement the following monitoring schedule:

• Measure TSH levels to document thyroid function status, as higher TSH levels are associated with increased risk for differentiated thyroid cancer. 2

• Perform high-resolution ultrasound at 12-24 months to assess for interval growth or development of suspicious features (microcalcifications, irregular margins, marked hypoechogenicity, central hypervascularity). 2, 3

• Monitor for compressive symptoms including dysphagia, dyspnea, voice changes, or cosmetic concerns at each follow-up visit. 2, 4

• Annual clinical evaluation with thyroid palpation and TSH measurement is sufficient for stable nodules without concerning features. 4

Indications for Surgical Intervention

Surgery should be considered only when specific criteria are met:

• Compressive symptoms clearly attributable to the goiter (dysphagia, dyspnea, stridor) that impair quality of life. 2, 4

• Large nodules >4 cm due to increased false-negative rate on FNA and higher risk of compressive symptoms. 2, 5

• Development of suspicious ultrasound features on surveillance imaging (microcalcifications, irregular borders, marked hypoechogenicity, loss of peripheral halo). 2

• Significant nodule growth (>20% increase in two dimensions or >50% volume increase) during follow-up, particularly in high-risk patients. 6

• Patient-driven cosmetic concerns that significantly impact quality of life, though this is a relative indication. 2

Role of Levothyroxine Suppression Therapy

Levothyroxine suppression is controversial and generally not recommended for multinodular goiter management. 4 The evidence shows:

• Suppression therapy is often unsuccessful in decreasing MNG size. 4
• Avoid levothyroxine in patients with suppressed TSH to prevent iatrogenic hyperthyroidism and associated cardiovascular/bone complications. 4
• Modest but stable goiters with normal TSH are best managed by yearly observation rather than suppression therapy. 4

High-Risk Features Requiring Repeat FNA

Perform repeat ultrasound-guided FNA if any of the following develop:

• History of head and neck irradiation (increases malignancy risk approximately 7-fold). 2
• Family history of thyroid cancer, particularly medullary carcinoma or familial syndromes. 2
• Rapidly growing nodule or change in morphological characteristics over time. 6
• Firm, fixed nodule on palpation suggesting extrathyroidal extension. 2
• New vocal cord paralysis or hoarseness indicating possible recurrent laryngeal nerve involvement. 2
• Suspicious cervical lymphadenopathy on physical exam or ultrasound. 2, 5

Critical Pitfalls to Avoid

Do not override worrisome clinical findings based solely on benign FNA results, as false-negative rates range from 11-33% and increase with nodule size >4 cm. 1, 2 Repeating FNA is warranted in patients with longstanding thyroid nodules, particularly those at increased risk or with changing morphology. 6

Do not perform molecular testing (BRAF, RAS, RET/PTC, PAX8/PPARγ) for Bethesda II nodules, as the pretest probability of malignancy is so low (1-3%) that molecular markers add minimal clinical value. 2 Reserve molecular testing for Bethesda III (AUS/FLUS) or IV (follicular neoplasm) categories. 2

Avoid radioiodine scanning in euthyroid patients with benign FNA results, as ultrasound features are far more predictive of malignancy risk than nuclear medicine studies. 2, 3

Special Consideration for Cystic Components

For nodules with both solid and cystic components, the solid portion carries the highest malignancy risk and should be the target for FNA sampling under ultrasound guidance. 2 Pure cystic nodules without solid components or suspicious features can be safely observed without FNA. 2

The overall malignancy rate in thyroid nodules within multinodular goiter is approximately 5%, comparable to solitary nodules, so the possibility of malignancy should always be considered. 7