A thyroid nodule biopsy is a procedure that removes a small piece of tissue from the thyroid gland for testing. It helps your doctor determine if the nodule is benign (noncancerous) or malignant (cancerous).

Your thyroid gland is a butterfly-shaped gland located in the front of your neck. Its function is to secrete thyroid hormones. These hormones are involved in metabolism and protein synthesis.

If you develop a solid or fluid-filled bump in your thyroid gland, it’s called a nodule. Thyroid nodules are common, but most are benign. However, your doctor will likely recommend a thyroid biopsy to examine the nodule.

This article will help explain who needs a biopsy, what the procedure involves, and the possible risks and side effects.

An imaging test can help your doctor identify a thyroid nodule, but it can’t determine if the nodule is malignant (cancerous). A thyroid nodule biopsy is the standard procedure for determining if nodules are cancerous.

However, not everyone with a thyroid nodule needs a biopsy. It depends on the size of the nodule and your risk of thyroid cancer.

In general, you might be a good candidate for a thyroid nodule biopsy if you have:

  • a nodule bigger than 1 centimeter (cm) and a moderate to high risk
  • a nodule larger than 1.5 cm and a low risk
  • a nodule larger than 2 cm and a very low risk

Your doctor can determine your risk by examining your imaging test results. They’ll analyze the nodule for certain features.

About thyroid nodules

It’s important to note that thyroid nodules are common. Additionally, most thyroid nodules are benign. Only about 5% to 10% are cancerous.

There are several types of thyroid biopsies. They’re similar in terms of accuracy, but some types have more risks.

Fine-needle aspiration

The most widely used thyroid biopsy is called fine-needle aspiration. That’s because it’s associated with fewer side effects. It also has a mean diagnostic accuracy approaching 95%.

In this procedure, a fine needle is inserted into the nodule. The needle removes, or suctions out, some of the substances in the nodule for examination.

Core needle biopsy

If a fine-needle aspiration doesn’t provide clear results, your doctor might recommend a core needle biopsy. This procedure is similar, but it uses a larger needle.

It has a similar accuracy rate to fine-needle aspiration. However, due to the bigger needle, there’s a higher risk of injuring the trachea and the carotid artery. That’s why fine-needle aspiration is a more popular option.

Surgical biopsy

Surgical biopsy, or open thyroid biopsy, is rarely used. It’s a procedure that involves cutting directly into the nodule and removing a sample of tissue.

The primary purpose of a thyroid biopsy is to diagnose cancer.

It can also detect noncancerous thyroid issues. Examples include:

A thyroid nodule biopsy is a simple procedure. It can be done at your doctor’s office and takes about 30 minutes to complete.

Since you won’t be given general anesthesia, you can go home right after the procedure.

The steps are similar for all types of thyroid biopsies. In a core needle biopsy, the needle will be bigger.

In an open thyroid biopsy, your doctor will cut out the nodule and remove tissue samples. They will stitch the incision and apply pressure to manage any bleeding.

What to expect during a thyroid nodule biopsy

  1. Your doctor will first perform an ultrasound to confirm the nodule’s location.
  2. The skin around your thyroid nodule will then be sterilized. This will help reduce the risk of infection.
  3. Next, a topical or local anesthetic will be applied to the area. You’ll stay awake during the procedure, but you won’t feel anything.
  4. Your doctor will then insert a fine needle into the nodule for several seconds.
  5. When tissue from the nodule enters the needle, the doctor will remove it.
  6. The tissue is then placed on glass slides.
  7. The doctor repeats the process two to six times, using a new needle each time. This ensures there are multiple tissue samples.
  8. When the biopsy is done, the doctor will apply pressure to the area to manage any bleeding. You won’t need stitches.

A thyroid nodule biopsy typically isn’t painful. That’s because you’ll be given a topical or local anesthetic before the procedure.

A topical anesthetic is applied on top of your skin. A local anesthetic is injected into your skin. Your doctor will decide which approach is the best option for you.

As the anesthesia wears off, you may experience some discomfort in the area. You can take ibuprofen and apply an ice pack to relieve any pain.

Otherwise, there’s no major recovery required after a thyroid biopsy. You can continue your daily activities as usual.

Side effects from a thyroid nodule biopsy are rare. Possible complications include:

  • bleeding
  • infection
  • bruising
  • pain
  • swelling
  • injury to nearby structures

A thyroid nodule biopsy is a procedure that removes a small sample of tissue from your thyroid gland. It’s used to determine if a thyroid nodule is cancerous.

Your doctor may decide to order a thyroid nodule biopsy if your nodule is a certain size. Similarly, if you have specific risk factors, your doctor may decide that you need the procedure.

A thyroid nodule biopsy is painless and takes about 30 minutes. Side effects are rare, and in many cases, thyroid nodules are benign.