Symptoms What are the symptoms of a thyroid nodule? A thyroid nodule is a lump caused by a proliferation of thyroid cells within the normal thyroid gland. Most thyroid nodules do not cause any symptoms. Rarely, nodules can cause thyroid pain, difficulty swallowing or breathing, hoarseness, or symptoms of hyperthyroidism. Etiology Thyroid nodules are the most important cause of thyroid cancer. Fortunately, only 10% of thyroid nodules become cancerous (see the Thyroid Cancer Handbook), which means that about 9 out of 10 nodules are benign (non-cancerous); these include colloid nodules, follicular tumors, thyroid cysts, and isolated nodules that overproduce thyroid hormones occasionally leading to hyperthyroidism. We do not yet know exactly what causes most non-cancerous thyroid nodules to grow. Diagnosis How are thyroid nodules diagnosed? Most thyroid nodules are found during other tests of the neck. Blood tests for thyroid hormone and thyroid stimulating hormone (TSH) are usually normal. You may need a thyroid biopsy, thyroid scan, and/or thyroid ultrasound to determine if the nodule is malignant. A fine needle biopsy of the thyroid can be performed in the exam room. Patients have no adverse effects after the procedure and can usually go home and continue working. Your primary care physician will use a very fine needle to aspirate cells from the thyroid nodule and place the aspirated cells under a microscope for examination. 50-60% of biopsies are benign (non-cancerous) and about 5% of biopsies find cancerous cells. About 10% of biopsies are suspicious and will undergo further testing (thyroid scan) or surgery. Up to 20% of biopsies will not have enough cells to make an accurate diagnosis, and a second puncture biopsy may be performed to further define the benign or malignant nature of these thyroid nodules. Thyroid scan A small amount of radioactive material, usually radioactive iodine, is used in the thyroid scan to obtain images of the thyroid gland. Patients with cold nodules must have a fine needle aspiration biopsy. A “cold” nodule means that the thyroid nodule is not functioning properly. A hot or functioning nodule means that the nodule is taking up more or as much radioactive iodine as normal thyroid cells, and these thyroid nodules are very unlikely to be cancerous. Ultrasound of the thyroid gland Ultrasound of the thyroid gland uses sound waves to obtain a picture of the thyroid gland, which can determine whether a nodule is solid or cystic. Ultrasound can be used to look for changes in benign thyroid nodules. Ultrasound of the thyroid gland during fine needle aspiration may also be indicated for accuracy of local puncture within the nodule. Ultrasound is particularly helpful if the examination of thyroid nodules is difficult. Treatment How are thyroid nodules treated? An experienced thyroid surgeon who wishes to treat thyroid cancer must remove all thyroid nodules and should remove all thyroid nodules in order to prevent the development of thyroid cancer. Benign thyroid nodules need to be reviewed regularly, at least once a year. Thyroid hormone suppression therapy should be given to reduce the size of the nodules.