What are the next steps for an elderly patient with an incidental 1.2cm thyroid nodule discovered on Computed Tomography (CT) scan?

Management of Incidental 1.2cm Thyroid Nodule in an Elderly Patient

The next step is to obtain a dedicated thyroid ultrasound with TSH measurement, followed by fine-needle aspiration (FNA) if the nodule meets size and suspicious feature criteria on ultrasound. 1

Initial Diagnostic Workup

Thyroid Ultrasound

• Perform a dedicated thyroid and central neck ultrasound to characterize the nodule and evaluate for suspicious lymph nodes, as this is essential for risk stratification 1
• The ultrasound should assess specific features including:
  • Solid vs. cystic composition (cystic or spongiform appearance suggests benign process) 2
  • Echogenicity (hypoechogenicity is suspicious) 2
  • Margin characteristics (irregular margins are concerning) 2
  • Presence of microcalcifications (suspicious feature) 2
  • Shape (spherical nodules have 18% malignancy risk vs. 5% in non-spherical) 3
• Add lateral neck ultrasound if concerning features are present in the thyroid nodule or central neck 1

Laboratory Testing

• Measure TSH as the first laboratory test to assess thyroid function 1
• If TSH is suppressed, a radionuclide thyroid scan is indicated to identify hyperfunctioning nodules, which are rarely malignant and do not require FNA 4, 5

Fine-Needle Aspiration Decision

When to Perform FNA

• For this 1.2cm nodule, FNA should be performed if suspicious ultrasound features are present 1
• The National Comprehensive Cancer Network recommends FNA for nodules ≥1-1.5 cm with suspicious ultrasound features 1
• Suspicious features warranting FNA include: solid composition, hypoechogenicity, irregular margins, microcalcifications 2
• FNA should also be performed regardless of size if suspicious lymph nodes are identified 1

When FNA Can Be Deferred

• Nodules <1 cm without suspicious features can be followed clinically without immediate FNA 1
• However, at 1.2cm, this nodule exceeds the threshold where observation alone is typically appropriate if suspicious features exist 1

Management Based on FNA Results

Benign Cytology

• Follow with ultrasound surveillance at appropriate intervals 1
• Most thyroid nodules are benign and can be safely managed with surveillance 2

Malignant Cytology

• Proceed to total thyroidectomy with or without central neck dissection depending on tumor size and other risk factors 1

Indeterminate Cytology

• Consider molecular testing to further stratify risk and guide surgical decision-making 1, 4
• Molecular testing detects mutations associated with thyroid cancer and helps inform decisions about surgical excision vs. continued monitoring 4
• Indeterminate cytology occurs in approximately 20-30% of all biopsies 2

Special Considerations for Elderly Patients

• Balance the risk of malignancy (approximately 10% of all thyroid nodules) against life expectancy and comorbidities 2
• The goal is to identify clinically significant cancers while avoiding overtreatment of indolent disease 2
• Consider that compressive symptoms occur in approximately 5% of nodules and functional disease in approximately 5% 2

Critical Pitfalls to Avoid

• Do not skip the dedicated thyroid ultrasound - incidental findings on CT require proper characterization with thyroid-specific imaging 1
• Do not fail to measure TSH - missing hyperfunctioning nodules leads to inappropriate management, as these rarely require biopsy 1, 4
• Do not perform FNA on nodules with benign ultrasound features (cystic, spongiform) as this leads to unnecessary procedures 2
• Do not perform incomplete neck evaluation - missing regional lymphadenopathy changes management significantly 1
• Avoid overdiagnosis and overtreatment of small, indolent thyroid cancers, particularly in elderly patients with limited life expectancy 1