Mayo Clinic states that typical thyroid nodules, growths of extra thyroid tissue on the thyroid, do not cause symptoms. Large nodules are felt as lumps at the base of the neck. Sometimes the nodules grow large enough that the base of the neck appears swollen. If a large nodule presses on the trachea, it causes breathing difficulties, and if it presses on the esophagus, it causes swallowing difficulties.
In rare cases, thyroid nodules produce and excrete hormones typically excreted by the thyroid according to Mayo Clinic. This leads to too much of the thyroid hormone thyroxine being produced, and that causes hyperthyroidism. The symptoms of hyperthyroidism are heat intolerance, unexplained weight loss, tremors, nervousness and an irregular heartbeat.
Mayo Clinic maintains that small thyroid nodules that do not produce symptoms do not usually need treatment. Large nodules that interfere with breathing or swallowing are surgically removed. Nodules that cause hyperthyroidism are treated in the same fashion as regular hyperthyroidism. Options include using radioactive iodine to attempt to shrink the thyroid tissue, taking anti-thyroid medication or surgery if other methods fail.
According to Mayo Clinic, large thyroid nodules are sometimes cancerous. Cancerous nodules are removed along with the surrounding thyroid tissue. After surgery, the patient takes thyroid hormones to replace the hormones no longer produced by the thyroid.