Thyroid biopsy

The thyroid is a butterfly-shaped gland at the lower front of the neck. It makes hormones that set your body's pace, or metabolism. A thyroid nodule is a lump inside the gland. Nodules are very common, and they become more common with age. Many are found by chance on a scan done for another reason.

About 9 in 10 thyroid nodules are not cancer. Most are harmless overgrowths, fluid-filled cysts or part of an enlarged gland (goiter). Even when a thyroid cancer is found, most types grow slowly and are very treatable.

On ultrasound, the thyroid looks like two gray wings on either side of the windpipe. A nodule is a round area that is darker, brighter or mixed. Features like tiny bright specks, irregular edges or a shape taller than wide make us more likely to recommend a biopsy.

Not every nodule needs a needle. Radiologists score each nodule on ultrasound with a system called TI-RADS, based on what it looks like and its size. Suspicious-looking nodules are biopsied when smaller, while low-risk ones are biopsied only when larger or simply watched with follow-up ultrasounds.

Your endocrinologist or primary doctor will usually check your thyroid blood tests (TSH) first. A thyroid scan may show a nodule as cold, meaning it takes up little tracer. Cold nodules are common and are usually benign, but a biopsy is needed to tell for sure.

1. 1
   Positioning

   You lie on your back with a pillow under your shoulders so your head tips back and your neck is extended.

2. 2
   Ultrasound and numbing

   We find the nodule with ultrasound, clean the skin and numb it with a small amount of local anesthetic.

3. 3
   Taking the samples

   We pass a very thin needle into the nodule 2 to 5 times, a few seconds each, while watching on ultrasound. We ask you not to talk, cough or swallow during each pass. Sometimes a slightly larger core needle is used.

4. 4
   Finishing up

   We press on your neck for a few minutes to prevent bruising, then apply skin glue or a small bandage.

Most people feel pressure and a mild ache, sometimes spreading to the jaw or ear. Sedation is rarely needed, but it is available if you are very anxious.

Before a thyroid biopsy, I scan the whole neck myself, not just the nodule on the request, because I want to be sure we sample the one that matters most and check the nearby lymph nodes. I tell patients that swallowing is fine between passes, just not during them. The whole thing is usually over before people expect.

Fabio Komlos, MD, interventional radiologist · About Dr. Fabio Komlos

Results usually take 2 to 3 business days and go to the doctor who ordered the biopsy. Thyroid biopsy results are reported using the Bethesda system, which has six categories.

About 1 in 5 results fall in the indeterminate range. In that case, the lab can run a molecular test on the sample, looking for gene changes linked to cancer. Tests such as Afirma or ThyroSeq help many people with a low-risk result avoid surgery they do not need. We often collect an extra sample during the biopsy so this test can be done without a second visit.

1. Right after
   Rest for 15 to 30 minutes. An ice pack helps with soreness. You can eat, drink and drive yourself home if you had no sedation.
2. First day
   Mild neck soreness and a slight sore throat are common. You can shower the same day.
3. Days 1–2
   Avoid heavy lifting and hard exercise. Baths and swimming are fine from the next day.
4. Up to 2 weeks
   A bruise may appear and fade. Skin glue falls off on its own.

A thyroid biopsy is very safe. The main risk is bleeding, which usually causes only a bruise or small swelling that fades over 1 to 3 weeks. Large bleeding in the neck is rare but can press on the windpipe, which is an emergency. Infection and injury to the voice nerve are very rare.