Does it surprise you that roughly half of adults over age 40 could have thyroid nodules? Experts don’t believe they are occurring more often; rather, technology advances make them more likely to get detected.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
“We often find them on diagnostic imaging now, so it’s not like it was years ago when the patient or their doctor would find a lump on their neck,” says endocrinologist Christian Nasr, MD.
Today, small nodules are often found during diagnostic imaging for other conditions — during an ultrasound to check a carotid artery or a CAT scan of the chest, for example.
Physicians today are very aware of finding these nodules, and when they do, they want to check to see if they are cancerous or benign. Only a small percentage of the solid or fluid-filled growths are cancerous.
What happens if you find a nodule?
The primary way to diagnose the content of a thyroid nodule is with fine needle aspiration (FNA).
During the procedure, your doctor draws a tiny amount of blood from the nodule. That contains enough cells to differentiate between the different categories of nodules. Typically, the doctor performs the procedure with ultrasound assistance.
Some people mistake the procedure for a biopsy, but Dr. Nasr clarifies: “I don’t even mention a biopsy, because it’s not really a biopsy.”
Your doctor will usually take two or three different samples, but the procedure is fairly painless, Dr. Nasr says.
“Some patients will ask for lidocaine to numb the skin, and the patient will feel a little pressure when the needle goes in,” he says. “But we do not see any major bleeding because we’re only drawing a drop of blood.”
What happens with the fine needle aspiration results?
Your physician will discuss the results with you once they come back from the lab. Here are the important statistics you should know:
- About 70 percent of FNA results are benign.
The risk of being wrong about the diagnosis is about 1 to 5 percent, depending on the institution, Dr. Nasr says.“We will recommend a follow-up ultrasound at six months to look for nodules and to look at their size,” he says. “If we don’t see anything, then we will recommend a follow-up ultrasound in 18 months, and after that, we either stop monitoring or recommend another follow-up ultrasound in two to three years.”
- About 5 percent of FNA results are definitely positive for cancer.
The risk of being wrong about the diagnosis is also about 1 to 5 percent, depending on the institution, Dr. Nasr says.If the FNA shows papillary thyroid carcinoma, doctors typically recommend a total thyroidectomy. More recently however, doctors are recommending a lobectomy for papillary cancer less than 1 to 2 centimeters in diameter confined to the thyroid gland in a younger patient, Dr. Nasr says.
- Doctors classify between 5 and 10 percent as “suspicious for follicular neoplasm.”
This means there is about a 30 percent risk of cancer. Doctors typically recommend removing only that lobe, not the entire thyroid.“Still, 70 percent of the time, it’s not cancer in this case,” Dr. Nasr says. If a patient is reluctant to have the thyroid lobe removed, the doctor may offer a repeat FNA with molecular testing to further estimate the risk of malignancy. However, Dr. Nasr says the discussion on molecular testing is complex, he advises patients to discuss it in further detail with their doctor.
- In 2 to 5 percent, doctors classify the nodule as “suspicious for papillary cancer,” the most common cancer.
This means the risk of finding cancer goes up about 60 percent and your doctor will recommend either a lobectomy (removal of a lobe of the thyroid) or a total thyroidectomy.
- In less than 1 percent, doctors find a medullary thyroid cancer or an anaplastic cancer (rapidly dividing cells).
In this case, the doctor will likely recommend a total thyroidectomy. The stage of the cancer dictates the extent of the surgery in these cases, Dr. Nasr says.
- About 5-10 percent of FNA results will be non-diagnostic.
In this case, the doctor typically will repeat the FNA. Most of the time, the repeat FNA will give a diagnosis. If it is still non-diagnostic, the doctor may recommend a lobectomy vs. monitoring with ultrasound.
4 other ways your doctor can diagnose thyroid nodules
According to Dr. Nasr, there are four main ways doctors diagnose thyroid nodules:
- Symptoms: There are several symptoms that help doctors identify nodules:
- The old-fashioned way of someone discovering a lump in their neck
- Difficulty swallowing or a choking sensation
- Symptoms of an overactive thyroid (caused by too much thyroid hormone), such as a racing heart, heat intolerance, excessive sweating or weight loss
- Personal history of external radiation: Have you ever been exposed to external radiation? For example, have your doctors used radiation to treat lymphoma or head and neck cancer? “It takes a while before cancer is found in the thyroid after such radiation,” Dr. Nasr says.
- Personal or family history of cancer: Do you have a lot of cases of thyroid cancer in your family? Have you ever had a melanoma, or breast, lung or kidney cancer? That increases your risk and makes your physician pay close attention.
- Ultrasound imaging: Your doctor will use this diagnostic tool to look at the size and composition of the nodule to see if it is solid or if it is a cystic nodule with fluid in it.
“Ultrasound is the best tool for us to triage these thyroid nodules further,” Dr. Nasr says. “We also look at the rest of the thyroid, because about 50 percent of patients will have another nodule or possibly several, so we need to make sure we look at all of them.”
Based on your personal and family history, the size of the nodule, the blood flow to the nodule and any calcification they find, your physician will decide whether or not to test your nodule or nodules, Dr. Nasr says.