To whom should I refer a patient with bilateral thyroid nodules for fine-needle aspiration (FNA)?

Referral for Fine-Needle Aspiration of Bilateral Thyroid Nodules

Patients with bilateral thyroid nodules requiring fine-needle aspiration (FNA) should be referred to an experienced endocrinologist or radiologist with expertise in thyroid ultrasound and FNA procedures. 1

Appropriate Specialists for Thyroid FNA

The selection of an appropriate specialist for thyroid FNA depends on several factors:

Primary Referral Options:

• Endocrinologists with specific training in thyroid ultrasound and FNA
• Radiologists with expertise in thyroid imaging and interventional procedures
• Head and neck surgeons/ENT specialists with thyroid expertise

Factors Affecting Referral Decision:

1. Specialist Experience:

   • Experience significantly impacts adequacy rates of FNA samples
   • Inadequacy rates: 3.1% for experienced physicians vs. 16.8% for inexperienced physicians 2
   • Higher experience correlates with better diagnostic accuracy

2. Institutional Resources:

   • Availability of on-site cytopathology evaluation
   • Access to specialized thyroid pathologists
   • Multidisciplinary thyroid tumor boards

3. Nodule Characteristics:

   • Complex or suspicious nodules may benefit from specialists with higher volume practices
   • Nodules with suspicious ultrasound features (hypoechogenicity, microcalcifications, irregular borders, solid aspect, intranodular blood flow, taller-than-wide shape) require particular expertise 3

Indications for FNA of Thyroid Nodules

FNA should be performed in the following circumstances:

• Any thyroid nodule >1 cm in diameter 3, 1
• Nodules <1 cm with any of these risk factors:
  • History of head and neck irradiation
  • Family history of thyroid cancer
  • Suspicious features on palpation
  • Presence of cervical adenopathy
  • Suspicious ultrasound features 3, 1
• In multinodular goiter, nodules with suspicious ultrasound features should undergo FNA 3

Optimal FNA Procedure Components

For optimal outcomes, the FNA procedure should include:

1. Pre-procedure assessment:

   • Comprehensive thyroid ultrasound
   • Thyroid function tests
   • Serum calcitonin measurement (to rule out medullary thyroid cancer) 1

2. During procedure:

   • Ultrasound guidance (improves accuracy compared to palpation-guided FNA)
   • Multiple aspirations (typically 2-4 passes per nodule)
   • Proper technique to minimize inadequate samples

3. Post-procedure:

   • Immediate cytologic assessment when available
   • Clear follow-up plan based on cytology results

Common Pitfalls to Avoid

1. Inadequate sampling:

   • Referring to inexperienced operators increases inadequacy rates 2
   • Inadequate samples necessitate repeat procedures, increasing patient anxiety and costs

2. Misinterpretation of follicular lesions:

   • Follicular neoplasms have a 16-36% risk of malignancy on final histopathology 4, 5
   • Expertise in cytopathology interpretation is crucial

3. Overreliance on benign FNA results:

   • False negative rates of 8.6% have been reported 5
   • Clinical suspicion should override reassuring cytology when discordant

4. Unnecessary repeat FNA:

   • Routine repeat FNA for stable, previously benign nodules has limited utility 6
   • Reserve repeat FNA for nodule growth, new suspicious features, or inadequate initial samples

Follow-up After FNA

Follow-up depends on FNA results:

• Benign: Ultrasound monitoring at 6-12 month intervals initially, then annually if stable 1
• Nondiagnostic: Repeat FNA, preferably by a more experienced operator 1
• Indeterminate/Suspicious: Surgical consultation is typically warranted 3, 1
• Malignant: Referral for surgical management 1

In conclusion, referring patients with bilateral thyroid nodules to experienced endocrinologists or radiologists with specific expertise in thyroid ultrasound and FNA will optimize diagnostic accuracy and patient outcomes.