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  • January 2017
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Update on Thyroid Nodule Imaging Guidelines

  • Dr. Sharylee Barnes
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Illustration of the Thyroid
In Brief

In May 2016, The American Association of Clinical Endocrinologists (AACE), the American College of Endocrinology (ACE), and the Associazione Medici Endocrinologi (AME) issued the latest update of their Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules.

In May 2016, The American Association of Clinical Endocrinologists (AACE), the American College of Endocrinology (ACE), and the Associazione Medici Endocrinologi (AME) issued the latest update of their Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules1

One of the goals of this update was to stratify the risk represented by different ultrasound images of thyroid nodules. Older guidelines did not have the same emphasis on ultrasound patterns, which underwriters are seeing more frequently in attending physician statements2, 3, 4.

The update includes fine needle aspiration (FNA) recommendations as well as five histologic classifications and comprehensive treatment recommendations. The latter two will not be addressed in this brief report. The new update also addresses both the American and British Thyroid Associations ultrasound thyroid nodule classification schemes. 

Prevalence of Thyroid Nodules

Large nodules exist in 5% to 8% of the healthy adult population6, 8 whereas small nodules (<10 mm) exist in 50% to 60%1, 5. Only about 2.5% of all thyroid nodules are malignant 6,7.

Patient Characteristics

The presence of any historical or clinical findings can impact the interpretation of the guidelines from the AACE/ACE/AME. Adverse history can include personal or family history of thyroid cancer, multiple endocrine neoplasia (MEN), or personal history of neck irradiation. Clinical findings such as dysphonia, dysphagia, dyspnea, anterior neck pain, nodule enlarging on exam, lymphadenopathy, and presence of hypo- or hyperthyroidism add additional risk consideration 6, 8. Age under 14 years or over 70 also increases malignancy potential, as does being male1.

Guidelines: Malignancy Risk and Recommended FNA Based on Ultrasound Findings 1, 6, 7, 4, 9

Thyroid ultrasound results can be divided into favorable and unfavorable features. As the number of unfavorable features increases, so does the risk of malignancy 1, 6, 9, 10.
These guidelines are for individuals without adverse histories and clinical features described above in “Patient Characteristics” unless otherwise noted.

Any nodule <5 mm should be monitored and should not be biopsied with FNA regardless of the ultrasound characteristics. Even with the adverse features FNA is not recommended if scintigraphy shows normal function.

Patients with multinodular goiter have the same risk stratification guidelines for their nodules as would a patient with a solitary nodule1. For multinodular goiter, each nodule is classified and the nodules with the most adverse features should be biopsied. The guidelines support performing FNA on no more than two nodules1.

Class 1 Lesion: Low-Risk Malignancy - ~1%

  • cysts with fluid component >80%
  • isoechoic spongiform nodules, either confluent or with regular halo
  • FNA if >20 mm and with adverse patient history features present (described on previous page) or enlarging nodule

Class 2 Lesion: Intermediate Risk Malignancy - ~ 5% to 15%

  • not a definite benign appearance
  • cystic and some solid components
  • slightly hypoechoic, isoechoic, or indeterminate hyperechoic spots
  • ovoid to round shape
  • margins may be smooth or ill-defined
  • intranodular vascularization
  • continuous calcified rim
  • elevated stiffness at elastography
  • FNA if >20 mm

Class 3 Lesion: High-Risk Malignancy - ~50% to 90%

Has at least one of the following suspicious features:

  • markedly hypoechoic
  • spiculated or microlobulated margins
  • microcalcifications
  • height greater than width
  • disruption of a calcified rim
  • capsular abutment
  • pathologic lymphadenopathy
  • FNA if:
    • Nodule >10 mm
    • extension beyond the hyroid
    • pathologic lymph nodes
    • vascular features or mass effect on the jugular vein by the lymph nodes
    • consider FNA if nodule is 5 mm to 10 mm, depending on clinical setting

Managing Ultrasound Results

The principal goal of a thyroid ultrasound is to find or rule out cancer 1, 8, 5. If a nodule is found, appropriate clinical follow-up must acknowledge the dangers of over-investigation1,11, 12, which can include excess radiation, bleeding, surgical complications, anxiety, anesthesia risk, hospital-acquired infections, and scarring. Surgical complications can include vocal cord paralysis (due to nerve damage), hypothyroidism and hypoparathyroidism7, 11, 12.

Underwriting Considerations

Understanding the natural history of lesions found during thyroid imaging and whether or not they are meaningful to prognosis or represent increased mortality or morbidity risk is essential to underwriting.

Thyroid ultrasound reports are frequently encountered in attending physician statements. It is essential for risk assessors to understand the risk associated with findings even if not clearly stated in the report, and from there determine if appropriate follow-up testing has been scheduled or performed. The historical and clinical features of the proposed insured must also be considered in order to interpret ultrasound findings properly. Taking all of this information into consideration should assist in reaching an appropriate underwriting decision.

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Meet the Authors & Experts

Dr. Sharylee Barnes
Vice President and Medical Director, RGA


  1. The American Association of Clinical Endocrinologists (AACE), the American College of Endocrinology (ACE), and the Associazione Medici Endocrinologi (AME) Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules – 2016 Update. Endocrine Practice Vol 22 (Suppl 1) May 2016.
  2. Yoon JH, Shin HJ, Kim EK, Moon HJ, Roh YH, Kwak JY. Quantitative Evaluation of Vascularity Using 2-D Power Doppler Ultrasonography May Not Identify Malignancy of the Thyroid. Ultrasound Med Biol. 2015 Nov;41(11):2873-83.
  3. Moon HJ, Kwak JY, Kim MJ, Son EJ, Kim EK. Can Vascularity at Power Doppler US Help Predict Thyroid Malignancy? Radiology. 2010 Apr,255(1):260-9.
  4. Kwak JY, Jung I, Baek JH. Korean Society of Thyroid Radiology (KSThR); Korean Society of Radiology et al. Image Reporting and Characterization System for Ultrasound Features of Thyroid Nodules: Multicentric Korean Retrospective Study. Korean J Radiol. 2013 Jan-Feb; 14(1):110-7. 
  5. Gharib H, Papini E, Paschke R, Duick DS, Valcavi R, Hegedüs L, Vitti P; AACE/AME/ETA Task Force on Thyroid Nodules. American Association of Clinical Endocrinologists, Associazione Medici Endocrinologi, and European Thyroid Association medical guidelines for clinical practice for the diagnosis and management of thyroid nodules: executive summary of recommendations. J Endocrinol Invest. 2010;33(5 Suppl):51-6. 
  6. Yeung MJ, Serpell JW. Management of the solitary thyroid nodule. Oncologist. 2008 Feb;13(2):105-12. 
  7. Haugen BR, Alexander EK, Bible KC et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016 Jan;26(1):1-133.
  8. Perros P, Boelaert K, Colley S, British Thyroid Association et al. Guidelines for the Management of Thyroid Cancer. Clin Endocrinol (Oxf). 2014 Jul;81 Suppl 1:1-122.
  9. Campanella P, Ianni F, Rota CA, Corsello SM, Pontecorvi A. Quantification of cancer risk of each clinical and ultrasonographic suspicious feature of thyroid nodules: a systematic review and meta-analysis. Eur J Endocrinol. 2014 Apr 10;170(5):R203-11. 
  10. Laulund AS, Nybo M, Brix TH, Abrahamsen B, Jørgensen HL, Hegedüs L. Duration of thyroid dysfunction correlates with all-cause mortality. The OPENTHYRO Register Cohort. PLoS One. 2014 Oct 23;9(10):e110437.
  11. Abu-Yousef MM, Larson JH, Kuehn DM, Wu AS, Laroia AT. Safety of ultrasound-guided fine needle aspiration biopsy of neck lesions in patients taking antithrombotic/anticoagulant medications. Ultrasound Q. 2011 Sep;27(3):157-9.
  12. van Roosmalen J, van Hemel B, Suurmeijer A, Groen H, Ruitenbeek T, Links TP, Plukker JT. Diagnostic value and cost considerations of routine fine-needle aspirations in the follow-up of thyroid nodules with benign readings Thyroid. 2010 Dec;20(12):1359-65. 

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