Overview
Thyroid nodules are solid or fluid-filled lumps that form within the thyroid. The thyroid is a small gland that sits at the base of the neck, just above the breastbone.
Thyroid gland
The thyroid gland is located at the base of the neck, just below the Adam's apple.
Most thyroid nodules aren't serious and don't cause symptoms. Only a small number of thyroid nodules are cancer.
Most people don't know they have a thyroid nodule until a healthcare professional finds it during a routine medical exam. Or a thyroid nodule might show up on a scan that's done for another health reason.
But some thyroid nodules can get large enough to be seen. Or they might make it hard to swallow or breathe or cause voice changes.
Symptoms
Most thyroid nodules don't cause symptoms. But some nodules get so large that they can:
- Be felt.
- Be seen, often as a swelling at the base of the neck.
- Press on the windpipe. That can cause shortness of breath.
- Press on the tube that connects the throat to the stomach, called the esophagus. This can make it hard to swallow.
Some thyroid nodules can make too much of a hormone called thyroxine. The extra thyroxine can cause a condition called hyperthyroidism. It has symptoms such as:
- Unexplained weight loss.
- Increased sweating.
- Tremor.
- Feeling nervous.
- Rapid or irregular heartbeat.
When to see a doctor
Most thyroid nodules are not cancer and don't cause problems. But if you see swelling in your neck, especially if it affects breathing or swallowing, see a healthcare professional right away. This is to make sure the swelling isn't related to cancer.
Also see a healthcare professional if you have any symptoms of hyperthyroidism.
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Causes
Several conditions can cause nodules in the thyroid gland, including:
- Overgrowth of thyroid tissue. This is sometimes called a thyroid adenoma. It's unclear why this happens, but it isn't cancer. And it's not thought to be serious unless its size causes symptoms that bother you. Some thyroid adenomas can lead to hyperthyroidism.
- Thyroid cyst. Fluid-filled spaces in the thyroid called cysts most often come from thyroid adenomas that break down. Often, solid parts are mixed with fluid in thyroid cysts. Cysts usually are not cancer. But they sometimes have solid parts that are cancer.
- Multinodular goiter. A goiter is an enlarged thyroid gland. Lack of iodine in the diet or a thyroid problem can cause a goiter. A multinodular goiter has more than one nodule within the goiter. Its cause isn't clear.
-
Thyroid cancer. The chances that a nodule is a cancer are small. But see a healthcare professional for a nodule that is large and hard or causes pain or discomfort.
Factors that increase your risk of thyroid cancer include having a family history of thyroid or other endocrine cancers. A history of radiation from medical therapy or from nuclear fallout also raises the risk.
- Iodine deficiency. Lack of iodine in your diet sometimes can cause thyroid nodules. But iodine deficiency isn't common in the United States. That's because iodine is added to table salt and other foods in the United States.
Thyroid nodules
Enlargement of your thyroid can expand the gland well beyond its typical size and cause a noticeable bulge in your neck. This can be caused by single or multiple nodules, also called lumps, in your thyroid, or by an autoimmune process.
Complications
Complications of some thyroid nodules include:
- Problems swallowing or breathing. Large nodules or a multinodular goiter can cause neck discomfort and get in the way of swallowing or breathing.
-
Hyperthyroidism. Problems can happen when a nodule or goiter makes thyroid hormone. This leads to too much of the hormone in the body. Hyperthyroidism can cause weight loss, muscle weakness, not being able to handle heat, and being anxious or cranky. Complications of hyperthyroidism include an irregular heartbeat and thinning bones.
- Problems related to thyroid nodule surgery. If you have surgery to remove a nodule, you may need to take thyroid hormone replacement therapy for the rest of your life.
