Does a Thyroid Nodule Mean Thyroid Cancer?
Learn More About the Most Common Endocrine Problem in the US
Sep 17, 2009
A thyroid nodule is simply a lump or mass in the thyroid. According to the American Thyroid Association, as many as two-thirds of people will develop a thyroid nodule during their lifetime. Nodules are usually discovered in the thyroid when a patient has a test for something else, like an ultrasound of their carotid arteries, a chest X-ray or a neck CT scan. Many thyroid lumps are found by healthcare providers during a routine physical exam. The cause of benign thyroid nodules is unknown.
Thyroid Nodule Symptoms
Most patients experience no symptoms and are unaware that they have a thyroid mass. Nodules may be small, less than 1 centimeter in size (slightly smaller than half an inch) or large, up to 7 or 8 centimeters. Larger nodules may actually be visible in the neck and can even extend down under the collar bones. Some symptoms of large thyroid masses are:
- difficulty swallowing
- difficulty breathing
- feeling a lump in the throat that won't go away
- pain in the ear, jaw or neck
- hoarseness
Approximately 90% of the time, thyroid nodules are benign. Further testing is necessary to discover which nodules are actually a type of thyroid cancer.
Thyroid Ultrasound
An ultrasound is performed of the thyroid to learn more about a nodule. This imaging test shows:
- nodule size
- presence of other nodules
- nodule texture
- whether the nodule is solid or full of fluid (a thyroid cyst)
- blood flow to the nodule
If a thyroid nodule is greater than one to 1.5 centimeters in size, a biopsy is usually recommended. Smaller thyroid masses may be biopsied if they have suspicious characteristics like calcifications or increased blood flow.
Thyroid Fine Needle Aspiration (FNA)
A thyroid biopsy is a simple procedure usually performed in the physician's office. Local anesthetic may or may not be used to numb the neck. The healthcare provider uses the ultrasound machine to locate the nodule. Small, very fine needles are then inserted into the nodule to extract some of the thyroid cells. The thyroid FNA takes only 15 to 20 minutes and patients can return to normal activities that day. Pressure and ice may be applied after the procedure to help decrease swelling and soreness. Results are usually available within a week.
Thyroid Scan
A thyroid scan may be ordered after an ultrasound to help determine whether the thyroid nodule is making extra thyroid hormone. A patient is given a small dose of radioactive iodine, then he undergoes a scan four to six hours later and again the next morning. Nodules may appear on a scan as hot, warm, cold or absent.
- hot nodule: the nodule is producing excess thyroid hormone
- warm nodule: the nodule may be producing slight more thyroid hormone
- cold nodule: the nodule may be benign or malignant
- absent: the nodule does not show up on the scan
This test is only helpful if the healthcare provider is concerned about an overactive thyroid nodule. Thyroid blood levels should be checked. If the TSH is low, the patient's nodule may be making excess thyroid hormone. These types of nodules are rarely malignant. Thyroid scans cannot prove that a nodule is malignant.
Thyroid Treatment and Monitoring
If a thyroid nodule is found to be malignant on FNA, the thyroid is removed. Overactive nodules or large nodules may be treated with radioactive iodine or surgery. Benign nodules may be watched over time by repeating ultrasound measurements annually and looking for any changes. If the nodule increases in size, the biopsy may be repeated. Patients with thyroid nodules should call their healthcare provider if they notice any changes or symptoms.
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