A thyroid nodule was found. What happens next?

Being told you have a “nodule” or a “lump” in your thyroid is frightening. Most people immediately think of cancer. The reassuring truth is that thyroid nodules are extremely common and the large majority are harmless. With the right steps, doctors can usually tell which nodules need attention and which can simply be watched.

What is a thyroid nodule?

A nodule is a lump of tissue inside the thyroid gland. It may be solid, filled with fluid (a cyst), or a mix of both. Some people have one nodule. Others have many, which is called a multinodular goitre.

Nodules are found in up to two out of three adults when an ultrasound is done carefully, and they become more common with age and in women. Many are discovered by chance, during a scan of the neck or a CT done for some other reason.

Is it cancer?

Usually not. Large reviews estimate that only about one in ten nodules is a cancer that matters clinically. Even when it is cancer, most thyroid cancers are slow-growing and have an excellent outlook with treatment. Doctors also look for two other things: whether the nodule is big enough to press on the windpipe or food pipe, and whether it is making too much thyroid hormone.

What tests come first?

Two simple tests guide almost everything:

1. A TSH blood test. If TSH is low, the nodule may be making extra thyroid hormone, a “hot” nodule. Hot nodules are almost never cancer, and your doctor may order a thyroid scan instead of a needle test. Read low TSH with high T4. If TSH is normal or high, the next step is ultrasound. For help reading your blood report, see the thyroid function test explained.
2. A thyroid ultrasound, done by an experienced radiologist or endocrinologist. This is the most important test for a nodule.

What does TIRADS on my ultrasound report mean?

TIRADS is a scoring system that turns the ultrasound appearance into a risk level. Indian reports may use the American (ACR TI-RADS) or the European (EU-TIRADS) version. They are similar in spirit.

The radiologist looks at a few features:

• What it is made of. Fluid-filled or “spongiform” nodules are very low risk.
• How dark it looks compared with normal thyroid. Very dark (markedly hypoechoic) solid nodules are higher risk.
• Its shape. A nodule that is “taller than wide” is more suspicious.
• Its edges. Irregular or spreading edges are more suspicious than smooth ones.
• Tiny bright spots (microcalcifications), which raise suspicion.

In plain words:

Score	What it usually means
TIRADS 1 or 2	Normal or benign-looking. Usually no needle test needed
TIRADS 3	Low suspicion. Needle test only if the nodule is fairly large
TIRADS 4	Moderate suspicion. Needle test above a smaller size
TIRADS 5	High suspicion. Needle test even when quite small

The exact size cut-offs differ between systems, so your doctor reads the score and the size together.

What is FNAC and does it hurt?

FNAC (fine-needle aspiration cytology) uses a very thin needle, usually guided by ultrasound, to draw out a few cells from the nodule. It takes a few minutes, is done in the clinic or radiology room, and feels similar to a blood test. Most people go home straight away. Bruising or mild soreness for a day is the most common after-effect.

The cells are read by a pathologist using the Bethesda system, which has six categories:

• Bethesda I: not enough cells. Usually repeated after some weeks.
• Bethesda II: benign. The most common result. Usually just followed up with ultrasound.
• Bethesda III and IV: indeterminate. Not clearly benign or cancer. Options include a repeat FNAC, molecular testing where available, or surgery.
• Bethesda V: suspicious for cancer.
• Bethesda VI: cancer, most often papillary thyroid cancer.

What if I just need follow-up?

Most people with benign or low-risk nodules need nothing more than a repeat ultrasound after a year or two, and then less often if the nodule stays stable. A small increase in size is common and is not by itself a sign of cancer. Large nodules that cause pressure symptoms or a visible swelling may be treated with surgery, or in some centres with non-surgical options such as radiofrequency ablation.

Thyroid tablets are no longer routinely used to shrink benign nodules, as the benefit is small and too much thyroid hormone carries risks.

Does a nodule affect my thyroid function or pregnancy?

Most nodules do not change thyroid function, so thyroid hormone levels are usually normal. If you are pregnant, an ultrasound and FNAC can be done safely if needed, and many decisions can wait until after delivery. Read thyroid problems in pregnancy.

What should you ask your doctor?

• What is the TIRADS score and size of my nodule?
• Do I need an FNAC, or can we watch it?
• When should the next ultrasound be done?
• Are my lymph nodes normal on the scan?

A nodule is best assessed by someone who looks at ultrasound and FNAC results together. See who an endocrinologist is or book a consultation.