What is goiter? Goiter refers to an enlargement of the thyroid gland. This condition usually occurs when the thyroid gland is not making enough thyroid hormone, so it tries to compensate by growing in size. There are two varieties of simple goiter: endemic goiter, which occurs because of iodine deficiency in the diet, and sporadic goiter, which often develops for no known reason. In both cases, the primary symptom is an enlargement of the thyroid gland, a small gland in the front of the neck. While this article focuses on simple goiter, other causes of an enlarged thyroid gland are inflammatory conditions and nodules or tumors. Endemic goiter is very rare in the United States because of the use of iodized table salt; however, it occurs more frequently in other areas of the world. While the specific causes of sporadic goiter are often not known, they may include genetics and medication side effects. In addition to the characteristic lump that occurs with goiter, you may experience difficulty breathing or trouble swallowing, or you may have a cough or sore throat. In mild cases of goiter, you may have a small lump, which may not be accompanied by any other symptoms and therefore may not require treatment. In moderate cases due to iodine deficiency, iodine may be sufficient to treat the problem. In more severe cases, thyroid hormones, radioactive iodine, or surgery may be necessary to treat the goiter. Simple goiters may resolve spontaneously or with the addition of dietary iodine. If a serious goiter goes untreated, however, it may enlarge and begin to interfere with the normal production of thyroid hormones. Both hypothyroidism and hyperthyroidism can result. Seek immediate medical care (call 911) for serious symptoms of goiter, such as difficulty breathing. Seek prompt medical care for persistent or uncomfortable goiter, as leaving goiter untreated may lead to either hypothyroidism or hyperthyroidism.