An enlargement of the thyroid gland, often caused by iodine deficiency, is called a goitre. The thyroid sits at the front of the neck and uses iodine to make thyroid hormones. When iodine is scarce, hormone production can fall, prompting the pituitary gland to release more thyroid-stimulating hormone (TSH). Persistent stimulation can make thyroid cells grow, producing a visible or palpable swelling.
Goitres can be diffuse, affecting the gland relatively evenly, or nodular, involving one or more lumps. They do not always mean that the thyroid is underactive: a goitre may occur with normal hormone levels, hypothyroidism, or, in some cases, hyperthyroidism. Most goitres are benign, although a new or rapidly growing neck swelling still requires medical assessment.
The word goitre comes from the Latin gutturia, meaning “throat.” Iodised salt, introduced in public-health programs during the early twentieth century, greatly reduced iodine-deficiency goitre in many regions. The American spelling is “goiter.” A thyroid nodule is a specific lump within the gland, whereas goitre refers to enlargement of the gland as a whole.