Thyroid Nodules & Multinodular Goiter

KEY FEATURES

Essentials of Diagnosis

• Single or multiple thyroid nodules are commonly palpated by the patient or clinician or discovered incidentally on imaging studies

• Thyroid function tests recommended

• Fine-needle aspiration (FNA) cytology for thyroid nodules ≥ 1 cm diameter or for smaller nodules in patients with a history of prior head-neck or chest-shoulder radiation

• Ultrasound guidance improves FNA diagnosis for palpable and nonpalpable nodules

• Clinical follow-up required

General Considerations

• Thyroid nodules are extremely common; most are at least 1 cm in diameter

• Most patients with a thyroid nodule are euthyroid, however, there is a high incidence of hypo- or hyperthyroidism

• Patients with palpable nodules require thyroid function testing and evaluation for thyroid malignancy

• The risk of a thyroid nodule being malignant is higher in males and among patients with

  • History of head-neck radiation, total body radiation for bone marrow transplantation, exposure to radioactive fallout as a child

  • Family history of thyroid cancer or a thyroid cancer syndrome (eg, Cowden syndrome, multiple endocrine neoplasia type 2, familial polyposis, Carney syndrome)

  • Personal history of another malignancy

  • Hoarseness or vocal fold paralysis, adherence to the trachea or strap muscles, cervical lymphadenopathy

  • Thyroid nodules that are solitary or large (≥ 4.5 cm max diameter)

• Overall risk of malignancy for thyroid nodules ≥ 1 cm in diameter is lower than previously thought; 1.2% overall and 2.8% in patients under age 30 (excluding papillary microfollicular carcinoma)

Demographics

• Thyroid nodules are much more common in women than men and become more prevalent with age

• Palpable nodules occur in 4–7% of adults

• Thyroid nodules are more common in iodine-deficient regions

CLINICAL FINDINGS

Symptoms and Signs

• Small thyroid nodules usually asymptomatic; may be detected by having the patient swallow during inspection and palpation of the thyroid

• Nodules can grow large enough to cause discomfort, hoarseness, or dysphagia

• Nodules that cause ipsilateral recurrent laryngeal nerve palsy are more likely to be malignant

• Retrosternal large multinodular goiters can cause dyspnea from tracheal compression

• Large substernal goiters may cause superior vena cava syndrome (facial erythema and jugular vein distention that progress to cyanosis and facial edema when both arms are kept raised over the head [Pemberton sign])

• Depending on their cause, goiters and thyroid nodules may be associated with

  • Hypothyroidism (autoimmune [Hashimoto] thyroiditis, endemic goiter)

  • Hyperthyroidism (Graves disease, toxic nodular goiter, subacute thyroiditis, and thyroid cancer with metastases)

Differential Diagnosis

• Iodine-deficient goiter

• Pregnancy (in areas of iodine deficiency)

• Graves disease

• Autoimmune (Hashimoto) thyroiditis

• Subacute (de Quervain) thyroiditis

• Medications causing hypothyroidism

  • Amiodarone

  • Interferon-α

  • Iodide

  • Lithium

  • Methimazole

  • Propylthiouracil

  • Sulfonamides

• Infiltrating disease (eg, malignancy, sarcoidosis)

• Infectious (suppurative) thyroiditis

• IgG₄-related thyroiditis (Riedel thyroiditis)

• Nonthyroid neck mass (eg, lymphadenopathy, lymphoma, ...