Thyroid nodules are growths that form on or in the thyroid gland. The causes are not always known but can include iodine deficiency and Hashimoto's disease. The nodules can be solid or fluid-filled. Most are benign, but they can also be cancerous in a small percentage of cases. As with other thyroid-related problems, nodules are more common in women than men and the risk in both sexes increases with age.Symptoms
Most thyroid nodules do not cause any symptoms. However, if they grow large enough, they can cause swelling in the neck and lead to breathing and swallowing difficulties, pain, and goiter. Some nodules produce thyroid hormone, causing abnormally high levels in the bloodstream. When this happens, symptoms are similar to those of hyperthyroidism and can include:
- High pulse rate
- Increased appetite
- Weight loss
- Clammy skin
On the other hand, if the nodules are associated with Hashimoto's disease, symptoms will be similar to those associated with hypothyroidism and can include:
Tests and Diagnosis
- Weigh gain
- Hair loss
- Dry skin
- Cold intolerance
Most nodules are detected during a normal physical exam. They can also be detected during an ultrasound, CT scan, or an MRI that is being done for unrelated head or neck conditions. Once a nodule is detected, other procedures—TSH test and a thyroid scan—can check for hyperthyroidism or hypothyroidism. A fine-needle aspiration (FNA) biopsy is used to take a sample of cells from the nodule and determine whether the nodule is cancerous.Treatment and Prognosis
Benign thyroid nodules are not life-threatening and usually don't require treatment. For larger noncancerous nodules that do need treatment, the outlook is excellent. If the biopsy reveals a benign nodule that is small in size, the treatment is often a "wait and see" approach that involves close monitoring with regular checkups. If the nodule does not change over time, nothing is usually done to remove it. If the nodule grows, another biopsy might be performed and treatment options might include radioactive iodine to shrink the nodules and hormone suppression to limit the amount of TSH and hormone tissue (hormone suppression's effectiveness is a matter of heated debate).
Cancerous nodules are pretty rare—estimated to be between 4% - 5% of diagnosed thyroid nodules. According to the National Cancer Institute, there are about 37,000 new cases of thyroid cancer diagnosed in the U.S. each year (compared to 219,000 new cases of lung cancer, for example). Treatment varies depending on the type of tumor. Removing the thyroid through surgery is usually the treatment of choice. Radiation therapy is sometimes used with or without surgery. If the cancer spreads to other parts of the body, chemotherapy is usually required.