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Thyroid nodules

Background

Overview

Definition
Thyroid nodules are solid growths in the thyroid gland that are radiologically distinct from surrounding thyroid parenchyma.
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Pathophysiology
Thyroid nodules may be benign (follicular adenoma, Hurthle cell adenoma, colloid cyst, simple or hemorrhagic cyst, lymphocytic thyroiditis, granulomatous thyroiditis, infectious processes) or malignant (malignancy of follicular or C-cell origin, papillary carcinoma, follicular carcinoma, Hurthle cell carcinoma, medullary thyroid carcinoma, anaplastic carcinoma, thyroid lymphoma, or malignancy metastatic to the thyroid).
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Epidemiology
The prevalence of thyroid nodules in the general population is > 65%. The estimated incidence of thyroid nodules in the US is around 0.1% per year.
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Risk factors
Risk factors for thyroid nodules include advanced age, female sex, tobacco use, higher BMI, metabolic syndrome, iodine deficiency, history of radiation exposure, elevated levels of TSH, increased thyroid volume, and autoimmune thyroid diseases.
Disease course
Large thyroid nodules can result in dysphagia, dyspnea, and dysphonia. Thyroid nodules may also become malignant over time.
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Prognosis and risk of recurrence
The risk of malignancy in thyroid nodules is around 4-6.5%.
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Guidelines

Key sources

The following summarized guidelines for the evaluation and management of thyroid nodules are prepared by our editorial team based on guidelines from the European Thyroid Association (ETA 2023,2022,2020), the American Academy of Family Physicians (AAFP 2020), the American Thyroid Association (ATA 2017,2016), the American College of Endocrinology (ACE/AME/AACE 2016), and the American Academy of Otolaryngology-Head and Neck Surgery Foundation (AAO-HNSF ...
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Screening and diagnosis

Indications for screening: as per AACE/ACE/AME 2016 guidelines, do not obtain screening ultrasound in the general population or patients with a normal thyroid on palpation and a low clinical risk of thyroid disease.
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Classification and risk stratification

Risk of malignancy
As per AACE/ACE/AME 2016 guidelines:
Recognize that most thyroid nodules are asymptomatic and benign but do not exclude malignancy based on the absence of symptoms.
B
Recognize that the risk of cancer is not substantially different in the case of a solitary nodule versus a multinodular goiter.
B
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Diagnostic investigations

History and physical examination
As per ETA 2023 guidelines:
Elicit a personal and family history and perform a physical examination in the initial evaluation of patients with thyroid nodules.
E
Consider using disease-specific patient-reported outcome measures for the evaluation of symptoms.
B
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  • Diagnostic imaging (ultrasound)

  • Diagnostic imaging (elastography)

  • Diagnostic imaging (CT/MRI)

  • Diagnostic imaging (PET)

  • Diagnostic imaging (radionuclide scan)

  • Laboratory tests (thyroid hormones and antibodies)

  • Laboratory tests (calcitonin)

  • Laboratory tests (parathyroid tests)

Diagnostic procedures

Core-needle biopsy: as per ETA 2023 guidelines, do not perform a core-needle biopsy as a first-line procedure to assess thyroid nodules after ultrasound evaluation. Consider performing core-needle biopsy as a second-line procedure for specific conditions.
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  • Fine-needle aspiration (indications based on nodule size)

  • Fine-needle aspiration (indications based on other characteristics)

  • Fine-needle aspiration (image-guidance)

  • Fine-needle aspiration (complex nodules)

  • Fine-needle aspiration (cystic nodules)

  • Fine-needle aspiration (multiple nodules)

  • Fine-needle aspiration (lymph nodes)

  • Fine-needle aspiration (aspirate washout)

  • Fine-needle aspiration (reporting)

  • Molecular testing

Medical management

Levothyroxine: as per ETA 2023 guidelines, do not initiate thyroid hormone treatment in euthyroid patients with nodular thyroid disease.
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  • Iodine supplementation

  • Selenium supplementation

  • Radioactive iodine therapy (indications)

  • Radioactive iodine therapy (pretreatment counseling)

  • Radioactive iodine therapy (pretreatment evaluation)

  • Radioactive iodine therapy (treatment monitoring)

Therapeutic procedures

Percutaneous ethanol injection: as per ETA 2023 guidelines, consider performing ethanol ablation as first-line therapy in patients with pure (or dominantly) cystic thyroid lesions.
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  • Thermal ablation (indications)

  • Thermal ablation (preprocedural counseling)

  • Thermal ablation (preprocedural evaluation)

  • Thermal ablation (anesthesia)

  • Thermal ablation (modalities)

  • Thermal ablation (postprocedural care)

Perioperative care

Preoperative imaging
As per AACE/ACE/AME 2016 guidelines:
Consider obtaining PET/CT for the preoperative staging of malignant nodules with aggressive features.
C
Consider obtaining MRI, CT, and/or 18F-FDG-PET/CT for more accurate preoperative staging in selected patients with aggressive features.
C
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  • Preoperative laboratory tests

  • Preoperative fine-needle aspiration

  • Preoperative voice assessment

  • Postoperative voice assessment

Surgical interventions

Diagnostic surgical excision: as per AACE/ACE/AME 2016 guidelines, consider performing surgery on persistently nondiagnostic solid nodules. Consider obtaining follow-up in a minority of solid nodules with clearly favorable clinical and ultrasound features.
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  • Indications for surgery (benign nodule)

  • Indications for surgery (indeterminate nodule)

  • Indications for surgery (suspicious nodule)

  • Indications for surgery (malignant nodule)

  • Indications for surgery (other indications)

  • Technical considerations for surgery (recurrent laryngeal nerve preservation)

  • Technical considerations for surgery (parathyroid gland preservation)

Specific circumstances

Pediatric patients, evaluation
As per ETA 2022 guidelines:
Obtain thyroid ultrasound to assess the risk of malignancy in a thyroid nodule based on multiple ultrasound characteristics. Do not use ultrasound alone to definitively distinguish a benign thyroid nodule from thyroid cancer. Perform FNA in patients with suspected nodules.
B
Obtain complete neck ultrasound to evaluate all cervical levels for the presence of lymph node enlargement in pediatric patients with thyroid nodules.
B
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  • Pediatric patients (monitoring)

  • Pediatric patients (surgery)

  • Pregnant patients (radionuclide scan)

  • Pregnant patients (FNA)

  • Pregnant patients (serum calcitonin)

  • Pregnant patients (management of benign nodules)

  • Pregnant patients (management of indeterminate nodules)

  • Pregnant patients (management of malignant nodules)

Patient education

Pretreatment counseling, radioiodine therapy
As per ATA 2016 guidelines:
Counsel female patients to avoid pregnancy for 6-12 months after receiving radioactive iodine.
B
Counsel male patients receiving cumulative radioactive iodine activities ≥ 400 mCi on potential risks of infertility.
B
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  • Pretreatment counseling (thermal ablation)

  • Pretreatment counseling (surgery)

Follow-up and surveillance

Management of treatment-related complications: as per ATA 2016 guidelines, insufficient evidence to recommend for or against the routine use of measures to prevent salivary gland damage after radioactive iodine therapy.
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  • Follow-up evaluation (incidentalomas)

  • Follow-up evaluation (asymptomatic nodules)

  • Follow-up evaluation (nondiagnostic by FNA)

  • Follow-up evaluation (benign by FNA)

  • Follow-up evaluation (indeterminate by FNA)

  • Follow-up evaluation (suspicious by FNA)

  • Follow-up evaluation (nodule growth)

  • Follow-up evaluation (after intervention)