Resident Editor: Hailyn V. Nielsen, MD, PhD

Fellow Editor: Tejaswi Komapla, MD

The following recommendations reflect the 2015 American Thyroid Association guidelines except as noted. These recommendations differ slightly from the 2016 guidelines put forth by a consortium of other groups including the American Association of Clinical Endocrinologists and the American College of Endocrinology. It is also notable that some sources cite the low prevalence of thyroid cancer and would advocate for less aggressive diagnostic work-up and monitoring than the guidelines set forth here.

Background

• ~1% of men and ~5% of women have a palpable thyroid nodule in iodine sufficient areas
• 19-68% of adults have incidental nodule(s) on ultrasound
• More common in women, elderly, areas with iodine deficiency
• 1.6-15% of thyroid nodules have evidence of malignancy
• Differentiated thyroid cancer is most common type (>90%)

Signs and Symptoms

• Clinical features concerning for malignancy: 
  • Childhood head and neck irradiation
  • Total body irradiation (as for bone marrow transplant)
  • Age<30 or age>60
  • Family history of thyroid cancer in a first degree relative
  • Family (first degree relative) or personal history of thyroid cancer syndromes (MEN2, FAP, Cowden’s syndrome, Carney complex, Werner syndrome/progeria)
  • Rapid growth of nodule
  • Hoarseness

Evaluation

• Perform complete history & physical exam with attention to signs and symptoms above
• For nodules discovered on physical exam, CT, MRI, or ultrasound (US), see Fig. 1
• For nodules discovered on ¹⁸FDG-PET imaging, see Fig. 2
• Risk of malignancy is best correlated with characteristics on thyroid ultrasound
• For patients with multiple nodules, evaluate each individually via Fig. 1 and Fig. 3. Prioritize FNA based on US characteristics. Some sources recommend biopsy of <= 2 nodules while others place no upper limit.
• For patients with multiple nodules which are all low or very low risk on US, reasonable to perform FNA only of largest nodule if >= 2 cm or observe with US.
• Do not biopsy nodules found to be hyperfunctioning on thyroid scintigraphy.

Management

• For toxic adenomas, see section on hyperthyroidism (as per Fig. 1)
• For nodules which do not meet criteria for FNA, monitor with US and clinical exam if indicated (as per Fig. 3)
• For nodules on which FNA is performed, see Fig. 4 for management and monitoring recommendations based on cytology result

When to Refer

• Refer to Endocrinology for toxic adenoma or hyperthyroidism
• Refer to Endocrine Surgery for diagnostic or therapeutic surgery as indicated
• Consider referral to Endocrinology for further risk stratification if cytology is indeterminate
• Consider referral to Endocrinology if molecular testing is ordered or desired
• Consider referral to Endocrinology if a familial syndrome is suspected
• Refer to Endocrine Surgery for management of symptomatic nodules 

References

Haugen, BR, Alexander, EK, Bible, KC, et al. 2015 American Thyroid Association Management Guidelines for Adult Patient with Thyroid Nodules and differentiated Thyroid Cancer. Thyroid. 2016; 26(1):1-133.

Alexander, EK, Pearce EN, Brent GA, et al. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid. 2017; 27(3):315-389.

Gharib, H, Papini, E, Garber, JR, et al. American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinologi Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules –2016 Update. Endocr Pract. 2016; 22(5):622-639. 

Ali SZ & ES Cibas, eds. The Bethesda System for Reporting Thyroid Cytopathology; Definitions, Criteria and Explanatory Notes. New York, NY: Springer; 2010.

Bongiovanni, M, Spitale, A, Faquin WC, et al. The Bethesda System for Reporting Thyroid Cytopathology: a meta-analysis. Acta Cytol. 2012; 55:492-498.