The term thyroid nodule refers to an abnormal growth of thyroid cells that forms a lump within the thyroid gland. It can be solid or filled with fluid. You can have a single nodule or a cluster of nodules in thyroid gland. Most thyroid nodules aren’t serious and don’t cause symptoms. Only a small percentage of thyroid nodules are cancerous.
A thyroid nodule can occur in any part of the gland. Some nodules can be felt quite easily. Others can be hidden deep in the thyroid tissue or located very low in the gland, where they are difficult to feel. You often won’t know you have a thyroid nodule until your doctor discovers it during a routine medical exam.
Types of Thyroid Nodules
There are several different types of thyroid nodules.
Toxic Nodules: This occurs when thyroid nodules, makes the thyroid gland overactive. In other words, thyroid gland starts producing excess thyroid hormones. It is known as toxic nodules. It may also lead to hyperthyroidism. In which the body’s metabolism speeds up. Toxic nodules may slowly become very large and press on surrounding structures in the neck or upper chest.
Toxic nodules are almost always benign (noncancerous), but they may require treatment to address hyperthyroidism.
Multinodular Goiter: When more than one nodules grow on thyroid gland the condition is called a multinodular goiter, or enlarged thyroid. Furthermore, Multinodular goiters can be either a toxic multinodular goiter (i.e. makes too much thyroid hormone and causes hyperthyroidism or non-toxic (i.e. does not make too much thyroid hormone and causes hypothyroidism).
It is associated with a higher risk of thyroid cancer. Up to 20 percent of people with multinodular goiters will also develop thyroid cancer. If you do have a multinodular goiter, your doctor will most likely screen you for thyroid cancer as well.
Thyroid Cyst: When thyroid nodules contain fluid, they are called cystic nodules. These can be completely filled with fluid known as simple cysts, or filled with partly solid and partly fluid known as complex cysts. Cysts are usually noncancerous, but they occasionally contain cancerous solid components.
Hot and Cold Nodules: Nodules detected by thyroid scans are classified as cold, hot, or warm. If a nodule is composed of cells that do not make thyroid hormone, then it is “cold”. If a nodule that is producing too much hormone is called “hot.”
85% of thyroid nodules are cold, 10% are warm, and 5% are hot. Remember that 85% of cold nodules are benign (noncancerous), 90% of warm nodules are benign, and 95% of hot nodules are benign.
Although thyroid scanning cannot truly differentiate benign or malignant nodules. Therefore, the evaluation of a thyroid nodule should always include history and examination by a physician. Remember, a biopsy is the only way to tell for sure that a nodule is benign or malignant.
Symptoms of a thyroid nodule?
Most thyroid nodules do not cause symptoms. Often, thyroid nodules are discovered incidentally during other routine physical examination. Occasionally, patients themselves find thyroid nodules by noticing a lump in their neck while looking in a mirror, buttoning their collar, or fastening a necklace.
However, if the thyroid nodule gets large enough, you may develop following symptoms:
- An enlarged thyroid gland, known as a goiter.
- A few people with thyroid nodules complain of pain at the site of the nodule that can travel to the ear or jaw.
- Breathing difficulties
- Swallowing difficulties
- Rarely, a person with a thyroid nodule may complain of hoarseness or difficulty speaking because of compression of the voice box.
Furthermore, if your thyroid nodule is producing excess thyroid hormones, you may also develop symptoms of hyperthyroidism, such as:
- Unexplained weight loss
- Increased sweating
- muscle weakness
- difficulty sleeping
- Rapid or irregular heartbeat
If production of your thyroid hormones is too low due to thyroid nodule, you may also develop symptoms of hypothyroidism, such as:
- Weight Gain
- Dry Skin
- Puffy Face
- Cold Sensitivity
Very rarely, nodules may cause pain or discomfort. But the most common of these symptoms is a lump in the neck followed by a sense of mass while swallowing.
What may cause thyroid nodules?
It’s not always clear why a person gets thyroid nodules. Several medical conditions can cause them to form. They include:
- Iodine deficiency
- Hashimoto’s disease, an autoimmune disease that leads to hypothyroidism.
- Thyroiditis or chronic inflammation of the thyroid.
Furthermore, cancer is the biggest concern when nodules form. Fortunately, cancer is very rare. Over 90% of such nodules are benign (noncancerous), but still, it is important to see a doctor if you think you have a nodule.
In addition, the risk for thyroid nodules is higher in women than men. Incidence increases with age, and is greater in people exposed to radiation from medical treatments
How are thyroid nodules diagnosed?
Thyroid nodules usually are discovered by the health care professional during routine physical examination of the neck. Once a nodule is discovered, a physician will use one or more of the following tests to diagnose and assess your nodule:
Ultrasonography: A physician may order an ultrasound examination of the thyroid to:
- Detect nodules that are not easily felt.
- Determine the number of nodules and their sizes.
- Determine if a nodule is solid or cystic.
Despite its value, the ultrasound cannot determine whether a nodule is benign or cancerous.
Thyroid Fine Needle Aspiration Biopsy (FNA or FNAB): For a fine needle biopsy, your doctor will use a very thin needle to withdraw cells from the thyroid nodule. Ordinarily, several samples will be taken from different parts of the nodule to give your doctor the best chance of finding cancerous cells if they are present.
The cells are then examined under a microscope by a pathologist to check if nodule is benign (noncancerous), malignant (cancerous) or suspicious for malignancy.
- Elevated levels of the thyroid hormones (T4 & T3) and low level of TSH (thyroid stimulating hormone) suggests hyperthyroidism.
- Abnormally low level of the thyroid hormones (T4 & T3) and elevated level TSH (thyroid stimulating hormone) suggests hypothyroidism.
- A antibodies test detects the antibodies against TPO (Thyroid Peroxidase) in the blood. The presence of TPO antibodies in your blood suggests that the cause of thyroid disease is an autoimmune disorder, such as Hashimoto’s disease or Graves’ disease.
Molecular Diagnostics: It examines the genes in the DNA of thyroid nodules. Therefore, these tests can provide helpful information about whether cancer may be present or absent.
These tests are particularly helpful when the specimen evaluated by the pathologist is indeterminate. These specialized tests are done on samples, which is obtained during the normal biopsy process. These are currently available only at highly specialized medical centers, however, their availability is increasing rapidly.
Thyroid Scans: Your doctor may recommend a thyroid scan to help evaluate thyroid nodules. During this test, an isotope of radioactive iodine is injected into a vein in your arm. You then lie on a table while a special camera produces an image of your thyroid on a computer screen.
Nodules that produce excess thyroid hormone — called hot nodules — show up on the scan because they take up more of the isotope than normal thyroid tissue does. Hot nodules are almost always noncancerous.
In some cases, nodules that take up less of the isotope — called cold nodules — are cancerous. However, a thyroid scan can’t distinguish between cold nodules that are cancerous and those that aren’t cancerous.
How are thyroid nodules treated?
Your treatment options will depend on the size and type of thyroid nodule you have.
Observation: If a thyroid nodule is benign (noncancerous) and small, the usual treatment is “watchful waiting.” This is not a form of active treatment but rather an observation period. Patients treated this way should be checked by their doctor every 3 months to monitor the growth of the nodule. As long as the nodule does not grow, there’s usually no need to worry.
Radioactive iodine treatment: Nodules that make too much thyroid hormone may be treated with radioiodine. It’s radioactive iodine that can be taken in a pill or liquid form. It helps reduce the size of the thyroid nodule without harming other tissue.
Surgery: If a nodule is cancerous or grows despite hormone pill treatment, surgery to remove the nodule may be needed. Almost all thyroid nodules that are malignant (cancerous) are treated by surgery. A noncancerous nodule may sometimes require surgery if it’s so large that it makes it hard to breathe or swallow.
Can thyroid nodules be prevented?
There’s no way to prevent the development of a thyroid nodule. However, most people who have thyroid nodules lead a normal life. You might need to check in with your doctor more often, but there usually are no complications.
Furthermore, if your thyroid nodules have symptom of thyroid cancer, you may need surgery. During the surgery, the doctor will remove most (if not all) of your thyroid. After the surgery, you’ll take daily thyroid replacement hormones for the rest of your life.