Thyroid Nodules
A thyroid nodule is an unusual lump (growth) of cells on
your thyroid gland. They’re common, almost always noncancerous (benign) and
usually don't cause symptoms. In rare cases, they're cancerous.
What are thyroid
nodules?
A thyroid nodule is an unusual lump (growth) of cells on
your thyroid gland.
Your thyroid gland is a small, butterfly-shaped endocrine
gland located in your neck, below your Adam's apple. It produces the hormones
thyroxine (also called T4) and triiodothyronine (also called T3). Thesehormones play a role in certain bodily functions, including:
Metabolism.
Body temperature.
Mood and excitability.
Pulse and heart rate.
Digestion.
Thyroid nodules are
classified as:
Solitary (a single nodule).
Multiple (more than one nodule).
Cystic (fluid-filled).
Solid.
More than 90% of detected nodules in adults are noncancerous
(benign), but they may represent thyroid cancer in approximately 4.0% to 6.5%
of cases. Even though most thyroid nodules aren’t cancer, they can sometimes be
a sign of and/or cause thyroid disease.
Who do thyroid nodules affect?
Anyone can have a thyroid nodule, including children and
adults. However, they’re about four times more common in people assigned female
at birth than people assigned male at birth.
They also occur more often in people who live in countries
in which food isn’t fortified with iodine. (Iodine is necessary for your
thyroid gland to make hormones.)
Other factors that lead to an increased risk of thyroid
nodules include:
History of thyroid radiation.
Family history of thyroid nodules or thyroid cancer.
Increasing age.
Iron-deficiency anemia.
Smoking.
Obesity.
Metabolic syndrome.
Alcohol consumption.
Increased levels of insulin-like growth factor-1 (a
hormone).
Uterine fibroids.
What symptoms can thyroid nodules cause?
Most thyroid nodules don’t cause symptoms. However, if you
have several nodules or large nodules, you may be able to see them.
In rare cases, nodules can grow big enough to cause the
following symptoms:
Trouble with swallowing or breathing.
Hoarseness or voice changes.
Pain in the front of your neck.
Enlargement of your thyroid gland (goiter).
Hyperfunctioning
thyroid nodules can lead to overproduction of thyroid hormones, also known as
hyperthyroidism. Symptoms of hyperthyroidism include:
Rapid heartbeat (palpitations).
Feeling shaky and/or nervous.
Weight loss.
Increased appetite.
Diarrhea and more frequent bowel movements.
Difficulty sleeping.
Enlarged thyroid gland (goiter).
Light or missed menstrual periods.
Thyroid nodules may
also be associated with low thyroid hormone levels (hypothyroidism). Symptoms
of hypothyroidism include:
Fatigue.
Numbness and tingling in your hands.
Weight gain.
Dry, coarse skin and hair.
Constipation.
Depression.
Frequent, heavy menstrual periods
What causes thyroid nodules?
Researchers don’t know why most thyroid nodules form.
Nodules can form for various reasons, and there are different types, including:
Colloid nodules:
These are one or more overgrowths of normal thyroid tissue. These growths are
not cancer (benign). They may grow large, but they don’t spread beyond your
thyroid gland. These are the most common type of thyroid nodules.
Thyroid cysts:
These are growths that are filled with fluid or are partly solid and partly
filled with fluid. Cystic nodules pose a low risk for cancer (malignancy) and
are either monitored or biopsied if they’re larger than 2 centimeters.
Inflammatory nodules:
These nodules develop as a result of long-term (chronic) swelling
(inflammation) of your thyroid gland. These growths may or may not cause pain.
Multinodular goiter:
Sometimes an enlarged thyroid (goiter) is made up of many nodules (which are
usually benign).
Hyperfunctioning
thyroid nodules: These nodules produce extra thyroid hormone, which may
lead to the development of hyperthyroidism. Hyperthyroidism requires treatment.
Thyroid cancer:
Cancer is the biggest concern when thyroid nodules form. Fortunately, thyroid
cancer is very rare — it’s found in less than 6.5% of all thyroid nodules.
DIAGNOSIS AND TESTS
How are thyroid nodules diagnosed?
Sometimes you can feel or see a thyroid nodule yourself, or
your healthcare provider may discover it during a physical exam. Your provider
may also discover a nodule with an imaging test done for another reason.
Even though thyroid nodules are almost always noncancerous
(benign), the small chance that it could be cancer means that most thyroid
nodules need some type of evaluation.
What tests will be done to diagnose and evaluate thyroid
nodules?
Your healthcare provider may order any of the following
tests to help diagnose and evaluate a thyroid nodule:
Thyroid blood test:
This test checks the levels of thyroid hormone in your blood. The hormone
levels are usually normal even if you have nodules, but they can be abnormal in
some cases and point to thyroid disease.
Thyroid ultrasound:
This is an imaging test that uses sound waves to create pictures of your
thyroid gland. It can determine if a nodule is solid or a fluid-filled cyst.
(The risk of cancer is higher in solid nodules.) This test also checks on the
growth of nodules and helps find nodules that are difficult to feel. In
addition, providers sometimes use ultrasound to help guide the placement of the
needle during a fine-needle biopsy.
Fine-needle biopsy:
With this test, your provider uses a very thin needle to take a sample of cells
from one or more thyroid nodules. They then send the samples to a laboratory
for evaluation. Most nodules are noncancerous. However, if the test results are
inconclusive, your provider may repeat this test. They may also suggest you
have surgery to remove the nodules to make an accurate diagnosis.
Thyroid scan: In
this test, you take a small amount of radioactive iodine orally. Your provider
will check to see how much of the radioactive iodine the thyroid nodules absorb
and how much is absorbed by normal thyroid tissue. This will provide further
information about the thyroid nodules, helping your provider determine the
likelihood of cancer
MANAGEMENT
AND TREATMENT
How are thyroid nodules treated?
Treatment depends on the type of thyroid nodule. Treatment
options include:
No treatment/watch and wait: If the nodules aren’t
cancerous, you and your healthcare provider may decide that you don’t need to
be treated at this time. You’ll see your provider regularly so they can check
for any changes in the nodules.
Radioactive iodine: Your provider may use radioactive iodine
to treat hyperfunctioning thyroid nodules and goiters with several nodules.
Your thyroid gland absorbs the radioactive iodine, causing the nodules to
shrink.
Surgery: Surgery to take out the nodules is the best
treatment for nodules that are cancerous, cause obstructive symptoms like
breathing or swallowing issues and are “suspicious” (they can’t be diagnosed
without being surgically removed and examined.
PREVENTION
Can thyroid nodules
be prevented?
Since researchers don’t know what causes the majority of
thyroid nodules, you can’t prevent them in most cases.
You can, however, try to decrease your risk of developing
them by managing certain risk factors. For example, if you have obesity, talk
to your healthcare provider about attaining a healthy weight for you. If you
smoke cigarettes, try to quit. It’s also important to make sure you get enough
iodine in your diet. If you use iodized table salt, you’re likely consuming
enough.
Studies have shown that people who take oral birth control
and/or statins may have a reduced risk of developing thyroid nodules.
