Thyroid nodules are one of the most common thyroid disorders—but they can also be a source of anxiety due to the possibility the nodule is cancerous.
While it’s natural to feel uncertain if you discover an abnormal lump or bump in your neck, most thyroid nodules aren’t cancer, and even the occasional cancerous ones are treatable. Here’s what you need to know and when to be concerned about thyroid nodules.
What is a thyroid nodule?
Your thyroid gland is a butterfly-shaped organ at the base of your neck right below your voice box (larynx). In some cases, as you age, abnormal growths form within your thyroid gland, called thyroid nodules. Some lumps are solid, some are fluid-filled and others are a mixture of both.
Thyroid nodule symptoms
Most thyroid nodules don’t cause any symptoms. You may not even realize you have a nodule until your doctor feels one during a routine medical exam or it shows up during imaging tests to evaluate another condition in your head or neck.
In most cases, thyroid nodules do not affect the function of your thyroid.
“Only rarely does a thyroid nodule get large enough to block the throat and cause difficulty swallowing or breathing,” said Keith Cryar, MD, an endocrinologist on the medical staff at Baylor Scott & White Medical Center – Temple.
Causes of thyroid nodules
Doctors do not know what causes most thyroid nodules, but they are common and increase with age. By age 60, roughly half of all individuals will have at least one nodule
There are other factors known to increase your risk for thyroid nodules. Among them:
- A family history of thyroid nodules
- Women are more likely to develop thyroid nodules, although men get them, too
- A chronic autoimmune condition known as Hashimoto’s Thyroiditis
- Radiation exposure
Evaluating thyroid nodules
If a nodule is found—either on a routine physical exam or with a CT or MRI scan—your doctor will want to rule out the possibility of cancer and make sure your thyroid is functioning correctly.
Blood tests that measure the levels of hormones made by your thyroid gland can signal how well your thyroid is working. Sometimes, a nodule can indicate hyperthyroidism (producing too much thyroid hormone) or hypothyroidism (producing too little thyroid hormone).
An ultrasound may be used to assess the nodule’s location and appearance and can show whether the lump is filled with fluid or solid. Solid nodules are more likely to be cancerous.
Fine needle aspiration (FNA)
FNA can determine if a thyroid nodule is benign or cancerous without resorting to surgery. It’s a simple, nearly pain-free procedure, requiring no restrictions afterward. In most cases, your endocrinologist will use ultrasound guidance to ensure accuracy.
FNA is performed in your endocrinologist’s office, often without even needing anesthesia. Patients who have undergone FNA both with and without local anesthesia most often report that the pain associated with injecting the local anesthesia is as severe or worse than the minor discomfort of the FNA needle.
“We usually take four or five samples by inserting very thin needles into the thyroid nodule,” Dr. Cryar said. “These small samples of thyroid tissue are sent for evaluation by a cytopathologist, an expert in interpreting tissue obtained by FNA.”
Treatment of thyroid nodules
Treatment of thyroid nodules depends on the type of nodule. More than 90% of thyroid nodules are noncancerous, and surgery is unnecessary.
Cancer or suspicious for cancer
The decision to undergo surgery depends on several factors. Although most thyroid cancers will be treated by surgical removal of the thyroid, some are so small and slow-growing that surgery is optional.
In some cases, the FNA sample cannot be definitively classified as cancer or benign. Depending on the microscopic appearance of the FNA, your endocrinologist may recommend more frequent ultrasound exams, a repeat FNA, partial removal of the thyroid, or genetic testing of another FNA sample.
Even if your thyroid nodule is benign, your endocrinologist will recommend repeat thyroid ultrasounds for several years to watch for any changes in the nodule.
“Growth of a nodule is considered suspicious for cancer until proven otherwise, and if the nodule grows, we will repeat the FNA to be certain the nodule does not contain undetected cancer,” Dr. Cryar said. “This process for evaluating and following thyroid nodules has allowed us to find and treat thyroid cancers aggressively while allowing most people with a nodule to avoid an unnecessary operation.”
Most thyroid cancers respond well to treatment and aren’t life-threatening, making early detection key.