When is Fine Needle Aspiration (FNA) recommended?

When to Recommend Fine Needle Aspiration (FNA)

Fine Needle Aspiration (FNA) should be used as the first-line modality for histologic assessment for any adult with a neck mass, particularly those at increased risk for malignancy. 1

Indications for FNA

Neck Masses

• Primary indication: Any adult with a neck mass deemed at increased risk for malignancy 1
• Risk factors for malignancy in neck masses:
  • Mass present for ≥2 weeks without significant fluctuation or of uncertain duration
  • Physical examination characteristics: fixation to adjacent tissues, firm consistency, size >1.5 cm, or ulceration of overlying skin
  • Other suspicious findings on history and physical examination

Thyroid Nodules

• Solid nodules >1cm with suspicious ultrasound features 2
• Any size nodule with highly suspicious features in high-risk patients 2
• Tender nodules with concerning ultrasound features 2
• Suspicious ultrasound features include: 2
  • Microcalcifications (highest risk, odds ratio 159)
  • Blurred/ill-defined margins (odds ratio 37)
  • Solid composition (odds ratio 9.9)
  • Hypoechogenicity (odds ratio 2.2)

FNA for Cystic Neck Masses

• FNA should be used for any adult with a cystic neck mass 1
• Clinicians should continue evaluation of patients with a cystic neck mass until a diagnosis is obtained and should not assume the mass is benign 1
• For cystic masses, FNA may need to be repeated, possibly with image guidance to direct the needle into solid components or the cyst wall 1
• While sensitivity of FNA is lower in cystic cervical metastases (73%) versus solid masses (90%), it remains the recommended first-line diagnostic approach 1

FNA Technique Considerations

• Ultrasound guidance should be considered when:
  • Initial palpation-guided FNA yields limited diagnostic utility
  • Evaluating cystic or necrotic masses (to target solid components)
  • Dealing with non-palpable nodules 1, 2
• On-site evaluation by a cytopathologist, when available, can reduce the inadequacy rate of FNA 1
• For suspected lymphoma, collection of material in tissue culture media is important to allow for immunophenotypic analysis 1
• When infection is considered, submission of some material for culture is recommended 1

Follow-up After FNA Results

Inadequate or Indeterminate Results

• Repeat FNA should be attempted prior to resorting to open biopsy for patients with worrisome signs and symptoms 1
• Add ultrasound guidance for repeat FNA to increase specimen adequacy 1
• Core biopsy is an option after an initial inadequate or indeterminate FNA, with high adequacy rate (95%) and accuracy (94-96%) 1

Special Considerations

• If history and physical examination strongly suggest lymphoma, core needle biopsy may be considered as first-line tissue sampling (sensitivity 92% vs 74% for FNA) 1
• For suspected malignancy where repeated FNA or image-guided FNA are inadequate or benign, expedient open excisional biopsy is recommended 1
• Excisional biopsy is preferred for cystic masses to reduce the risk of tumor spillage 1

When FNA May Not Be Necessary

• Solitary nodules in patients with strong family history of thyroid cancer, multiple endocrine neoplasia type II, or history of radiation to head and neck (these patients have >40% risk of thyroid cancer and should undergo surgery) 3
• Patients with multinodular goiter and compressive symptoms 3
• Patients with Graves' disease and a thyroid nodule 3
• Large (>4 cm) or symptomatic unilateral thyroid nodules 3
• Solitary hyperfunctioning nodules on radioiodine scan with suppressed TSH (extremely low malignancy risk) 3

FNA has dramatically improved the management of neck masses and thyroid nodules, increasing the rate of malignancy in surgically resected thyroid nodules from approximately 14% before routine FNA use to >50% currently 4.