A goiter is an enlargement of the thyroid gland, which is located in the front of the neck. This condition can occur for various reasons, including iodine deficiency, autoimmune diseases like Graves' disease, or the presence of nodules. Goiters can be small and cause no symptoms, or they can grow large enough to cause discomfort or difficulty swallowing and breathing. The most common cause of goiter worldwide is a lack of iodine in the diet, as iodine is essential for the production of thyroid hormones. In some cases, goiters may be associated with hypothyroidism or hyperthyroidism, conditions where the thyroid gland is underactive or overactive, respectively. Treatment options vary depending on the cause and severity of the goiter.