• Clinical science



Goiter is any abnormal enlargement of the thyroid gland. The condition has various causes, with the most common worldwide being iodine deficiency. In the US, however, Hashimoto's and Graves' disease are more common etiologies. Goiters can be classified based on their morphology, function, or dignity (benign or malignant). Symptoms depend on etiology and are often absent. However, patients may present with hyperthyroidism or hypothyroidism. Large goiters may also cause obstructive symptoms due to compression of the trachea and/or the esophagus. Diagnosis is established based on clinical examination, laboratory tests, and imaging techniques. Management depends on the underlying condition and may include administering iodine (for treating nontoxic euthyroid goiter) or performing surgery (e.g., for treating local compression or thyroid cancers).


  • Sex: > (4:1)
  • Frequency: decreases with age


Epidemiological data refers to the US, unless otherwise specified.




Thyroid gland versus goiter

  • Normal adult thyroid gland
    • Weight: ∼ 10–20 g
    • Volume: ∼ 7–10 mL
    • Location: caudal to larynx surrounding the anterolateral part of the trachea
  • Goiter
    • Enlarged volume of thyroid gland
    • Goiters can be differentiated based on
      • Morphology (growth pattern, size)
      • Thyroid function
      • Benignity/malignancy


Thyroid function of goiter

Dignity of goiter


Clinical features



Classification of goiter by palpation

According to the World Health Organization (WHO) classification:

  • Grade 0: no goiter is palpable or visible.
  • Grade 1: palpable goiter, not visible when neck is held in normal position
  • Grade 2: a clearly swollen neck (also visible in normal position of the neck) that is consistent with a goiter on palpation



  • Nontoxic goiter
    • Treatment is not needed if the patient is asymptomatic.
    • Schedule follow-ups for possible dysfunctional thyroid and/or obstructive symptoms.
  • Large goiter (> 80 mL)
    • Surgery is preferred to avoid complications (e.g., obstructive symptoms).
    • Alternatively, radioiodine therapy
  • Iodine deficiency: iodine supplementation
  • In other cases, goiter treatment varies depending on the exact etiology (see “Etiology” above).