What is the most appropriate management for a patient with toxic multinodular goitre (TMNG) and a 2 cm solid nodule on ultrasound (US), showing hyperthyroidism on a thyroid scan?

Management of Toxic Multinodular Goiter with a 2 cm Solid Nodule

Near total thyroidectomy or total thyroidectomy is the most appropriate management for a patient with toxic multinodular goiter (TMNG) and a 2 cm solid nodule on ultrasound showing hyperthyroidism on thyroid scan.

Rationale for Surgical Management

Toxic multinodular goiter with a significant nodule (2 cm) requires definitive treatment due to several key factors:

1. Persistent hyperthyroidism: TMNG represents autonomous thyroid function that will not remit with medical therapy alone 1

2. Risk of malignancy: A 2 cm solid nodule carries risk of malignancy (3-16.6% of apparently benign goiters contain incidental thyroid cancers) 2

3. Long-term outcomes: Total or near-total thyroidectomy provides definitive treatment for both hyperthyroidism and potential malignancy

Why Near Total/Total Thyroidectomy is Superior to Other Options

Compared to Subtotal Thyroidectomy (Option A):

• Subtotal thyroidectomy is associated with significant recurrence rates (up to 50%) 2
• Leaves potential malignant tissue behind if incidental cancer is present
• Does not provide significant safety advantage over total thyroidectomy 2

Compared to RAI Ablation (Option B):

• RAI is less effective for large multinodular goiters with large nodules 3
• Cannot address potential malignancy in the 2 cm solid nodule
• May require multiple treatments for complete resolution of hyperthyroidism
• Cold nodules within a toxic MNG will not take up radioiodine effectively

Compared to Right Thyroidectomy (Option C):

• Inadequate for multinodular disease that affects both lobes
• High risk of persistent hyperthyroidism from remaining thyroid tissue
• Would require a second surgery if malignancy is found

Preoperative Considerations

Before proceeding with surgery:

• Thyroid function tests to confirm hyperthyroidism
• Achieve euthyroidism with antithyroid medications before surgery
• Neck ultrasound to fully characterize nodules and assess lymph nodes
• Consider FNA of the 2 cm nodule to evaluate for malignancy

Surgical Approach

The procedure should be performed by an experienced thyroid surgeon to minimize complications:

• Total or near-total thyroidectomy with removal of all visible thyroid tissue
• Careful identification and preservation of recurrent laryngeal nerves
• Identification and preservation of parathyroid glands
• Intraoperative frozen section if suspicious findings are present

Postoperative Management

• Thyroid hormone replacement therapy to maintain euthyroidism
• Calcium monitoring for potential hypocalcemia
• Regular follow-up to ensure adequate hormone replacement

Common Pitfalls to Avoid

1. Underestimating the extent of disease: Subtotal thyroidectomy may leave autonomous tissue behind
2. Ignoring malignancy risk: A 2 cm solid nodule requires thorough evaluation
3. Delaying definitive treatment: Prolonged hyperthyroidism increases cardiac risks, particularly in older patients
4. Inadequate surgical expertise: Thyroidectomy should be performed by surgeons with substantial experience to minimize complications

In conclusion, near total or total thyroidectomy provides the most comprehensive solution for toxic multinodular goiter with a significant solid nodule, addressing both the hyperthyroidism and potential malignancy risk while minimizing recurrence potential.