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Thyroid Nodules

January 24, 2022

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A thyroid nodule is a growth of thyroid tissue or a fluid-filled cyst that forms a lump in the thyroid gland. Nodules are very common. The chances of developing nodules in the thyroid gland increase as you get older. Symptoms are not common, but a large nodule may cause pain or hoarseness or get in the way of swallowing or breathing. 

Most thyroid nodules are benign (not cancerous), but a small subset of thyroid nodules may harbor a thyroid cancer. Thyroid cancer is found in about 8% of nodules in men (or 8 out of 100) and in 4% of nodules in women. 

Endocrine Connection 

Thyroid nodules are a problem with the structure of the thyroid gland, but they very rarely impact thyroid function. Therefore, thyroid function is usually normal despite the presence of a nodule. Different types of thyroid nodules include:

Thyroid cysts: only contain liquid inside of them and are usually benign. These typically do not impact thyroid function. When they are causing discomfort, they can be drained with a needle, surgically removed, or ablated, or removed, using minimally invasive techniques.

Solid thyroid nodules: the majority of thyroid nodules, and most of these do not harbor cancers. These typically do not impact thyroid function and are evaluated by ultrasound.

Overactive ‘toxic’ thyroid nodules: Only a minority of thyroid nodules make extra thyroid hormone, and these are called toxic adenomasToxic adenomas are usually benign, and the options for treating these are similar to other causes of hyperthyroidism.  

The cause of most benign nodules is not known, but they are often found in members of the same family. Worldwide, lack of iodine in the diet is a very common cause of nodules. Thyroid nodules become more common with increasing age.  

Most thyroid nodules are found during a routine physical exam. Sometimes the nodules are noted on an x-ray study that includes the neck. If a thyroid is found, your doctor will check a blood test to learn if the thyroid is functioning normally. Sometimes, a nodule can be associated with hyperthyroidism (producing too much thyroid hormone) or hypothyroidism (producing not enough thyroid hormone). 

However, the blood tests are not enough to test for thyroid cancer. To gather more information about the nodule, your doctor might recommend one or more of the following tests: 

Thyroid Ultrasound: This is used to get an exact picture of the thyroid and see if the nodule is solid or filled with fluid (cystic). Thyroid nodules are evaluated based on their size, their position inside the thyroid, and other features of the nodule which can increase or decrease the chance that the nodule harbors a cancer.  Taking all these elements into account, your doctor may recommend a biopsy, continued monitoring by ultrasound, other types of imaging, or no further imaging at all. 

Fine-needle Aspiration Biopsy: This uses a thin needle to remove cells or fluid samples from the nodule and we often use the thyroid ultrasound as a guide to placing the needle for biopsy “ultrasound-guided fine needle aspiration biopsy”. Fine needle aspiration may be recommended if the nodule is larger than 1.0 centimeters or if it has any concerning features on ultrasound. This test is very helpful for identifying cancerous or "suspicious" nodules. This is usually an office procedure and is well tolerated by most patients.  

Thyroid Scan: This uses a small amount of radioactive iodine and a special camera to get a picture of the thyroid and learn if the nodule is overactive or under active. This procedure is usually done when the blood tests show hyperthyroidism, or too much thyroid hormone. 

Small thyroid nodules typically do not cause symptoms. However, larger nodules can press on the structures in the neck to cause: 

  • Breathing troubles 
  • Swallowing troubles 
  • Voice changes
  • Discomfort due to a fullness feeling in the neck 

We call all of these symptoms “compressive symptoms” because they are putting pressure on the neck; when there are compressive symptoms, that is usually a reason to have that part of the thyroid removed. Overactive “toxic” thyroid nodules can be associated with symptoms of hyperthyroidism as well as the neck symptoms described. 

Risk factors for solid thyroid nodules include increasing age, living in areas of iodine deficiency, and smoking.  Nodules harboring thyroid cancer are more common in men, are more likely with increasing age, and can be associated with exposure to childhood radiation and to smoking.  Most thyroid cancers are sporadic (not associated with a genetic condition) but there are some thyroid cancers that may be genetically inherited. 

Treatment depends on the type of thyroid nodule. If the fine needle aspiration shows cancerous or suspicious cells, experts usually recommend surgery to remove the thyroid gland. After surgery, radioactive iodine therapy may be used to destroy any remaining thyroid cells. 

Some benign nodules may need to be removed with surgery if they are very big and are causing problems with swallowing or breathing. Most benign nodules are watched without surgery. Hyper-functioning nodules are almost never cancerous, but they may cause hyperthyroidism, too much thyroid hormone in the body—which can lead to health problems. These nodules may be surgically removed or treated with radioactive iodine. 

If surgery is not recommended, your doctor may recommend continued monitoring of the nodule, which is usually done with thyroid ultrasound.  Monitoring intervals depend on the size and characteristics of the nodule.  If the nodule gets larger, you may need to have a repeat fine needle biopsy. 

If you think you have a thyroid nodule, see your doctor. Your doctor may refer you to an endocrinologist (a specialist in hormone-related conditions) for diagnosis and treatment. Then get the recommended treatment and follow up with your doctor as needed.  


  • What kind of nodules do I have? 
  • Are my symptoms related to my thyroid nodule? 
  • Am I at risk for thyroid cancer? 
  • Does my thyroid nodule require a biopsy? 
  • If monitoring is recommended, how often should I have monitoring?  What should I be looking for in the interim? 
  • What are the risks and benefits of each of my treatment options? 
  • Should I see an endocrinologist? 

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