Thyroid nodules are small lumps which develop in the thyroid gland, a gland located at the base of the neck. These growths are extremely common, appearing in an estimated 50% of all people, and the vast majority of them are benign. In fact, thyroid nodules have been discovered in greater numbers since the development of sophisticated medical imaging equipment, as they often show up on tests performed to look for other things. This would suggest that many people are living with thyroid nodules without knowing it.
There are a number of different types of thyroid nodules. One of the most common is a colloid nodule, caused by an overgrowth of thyroid tissue. Thyroid cysts are filled with fluid, making them soft to the touch, while inflammatory nodules are caused by irritation, infection, or inflammation. Hyperfunctioning thyroid nodules, associated with some thyroid diseases, produce hormones which trigger the thyroid to overproduce, causing hyperthyroidism. Another example of a type of thyroid nodule is a cancerous thyroid nodule.
Typically, thyroid nodules are discovered during a routine physical exam, because it takes training to detect a nodule. They may also show up on medical imaging studies of the neck. In most cases, there are no symptoms, although some people experience shortness of breath, anxiety, weight loss, or an increased heart rate, especially in the case of malignant nodules. Sometimes, the nodule grows large enough to press on the windpipe, making it hard to breathe, speak, or swallow.
If a doctor detects a thyroid nodule, the response is usually to order more testing to determine what kind of nodule it is. Blood can be drawn to check the levels of various thyroid hormones in the blood, and a doctor may also biopsy the nodule to test it directly. A thyroid scan can also be used as a diagnostic tool, to visualize the thyroid and get an idea about what is going in the thyroid.
After tests have been used to gather more information about the nodule, the treatment varies, depending on what type of nodule it is. Sometimes, the best treatment is no treatment, if the nodule is benign. If the nodule is malignant, as happens in around five to 10% of cases, the next step is often to remove the nodule, using radioactive iodine, surgery, or injections of alcohol to shrink the nodule. Some doctors also prescribe thyroid medications to reduce the amount of hormones being produced by the thyroid.