Overview: What is a thyroid nodule
About one in two people over the age of 50 has thyroid nodules. The thyroid gland is located in a butterfly shape on the neck below the larynx and produces the important thyroid hormone L-thyroxine (T4). It can change nodularly over the years: Cells of the thyroid restructure, become larger or multiply, and a nodule develops.
Around 95 percent of thyroid nodules are benign. They usually do not affect health unless the lump grows or is large, crowding the surrounding tissue. This can cause discomfort. So-called autonomous adenomas can also cause discomfort. These “hot” nodes produce increased thyroid hormones, thus leading to hyperthyroidism.
The remaining five percent of nodes are malignant nodes, usually thyroid carcinoma.
Thyroid nodules: Causes and risk factors
The most important cause for the development of a thyroid nodule is iodine deficiency, which is still present subliminally in Switzerland. Iodine is, so to speak, the fuel for the thyroid gland, which it needs to produce hormones. If it receives too little iodine, the gland reacts by enlarging. Their cells multiply in order to be able to absorb the little iodine available from the blood as completely as possible.
In addition, in the case of iodine deficiency, the body produces more of a certain hormone, thyroid-stimulating hormone (TSH). It is supposed to stimulate the production of thyroid hormones, which allows the cells of this gland to increase in size. Iodine deficiency thus changes the thyroid gland in two ways: its cells multiply and enlarge. This can cause goiter, benign nodules, but also cysts and in rare cases cancer.
Symptoms: From feeling of pressure to hair loss
Thyroid nodules usually grow slowly and often do not grow larger than one centimeter. Complaints and signs then often do not arise at all. Accordingly, thyroid nodules are often discovered only by chance, for example, during a carotid artery examination as part of an arteriosclerosis risk assessment.
Only when the thyroid nodule has reached a certain size, it oppresses the trachea and esophagus by growing and the following symptoms may occur:
- Feeling of pressure, tightness in the throat
- Difficulty swallowing
- persistent hoarseness
- Compulsion to constantly clear throat
If it is a hot nodule leading to hyperthyroidism, all the symptoms of hyperthyroidism may occur because the metabolism is excessively activated:
- Sleep disturbances
- Nervousness
- excessive sweating
- Weight loss
- Diarrhea
- Hair loss
Any of these signs should lead to seeking medical advice.
Physical examination and ultrasound
This is followed by the physical examination: we palpate the thyroid gland and the entire neck region with the local lymph nodes.
Ultrasound examinations are particularly informative, as they allow even small, non-palpable thyroid changes to be visualized. In order to better assess the nodes in terms of risk, there is a standardized measurement procedure. This is the TIRADS system (thyroid imaging reporting and database system). It is a 5-digit grading system that classifies nodes into “no risk,” TIRADS 1-2, “intermediate risk” TIRADS 3-4, and “high risk for thyroid cancer” TIRADS 5. At the same time, of course, the local lymph nodes are assessed.
A blood test with measurement of thyroid hormones provides further clues.
Clarify thyroid nodules with scintigraphy and biopsy
If these examinations have provided circumstantial evidence that the structure and function of the thyroid gland are altered, scintigraphy can provide further details if hyperthyroidism is suspected. In this diagnostic option, we inject you with a small amount of an iodine-like substance that is weakly radioactively labeled (called a radiopharmaceutical). The substance accumulates more in the active thyroid tissue. This means that it is a scintigraphically “hot” node. This is always benign, so further clarification is not necessary. If no radioactivity accumulates in the node, it is “cold”. If it is a cold nodule, taking a small tissue sample (fine needle aspiration) can clarify whether thyroid cancer is possibly present. For this purpose, the removed tissue is examined. If there is no suspicion of hyperthyroidism in the blood test, the ultrasound decides whether tissue removal from the node is necessary (according to TIRADS criteria).
Thyroid nodule: Diagnosis at the USZ
With a few simple examinations, we can clarify whether a thyroid nodule is the cause of the symptoms and, most importantly, whether it is benign or malignant.
At the beginning there is the anamnesis, where we ask you about complaints. We will also inquire about any special risk factors for thyroid cancer, such as whether you have a family history of this form of cancer or whether you have ever had radiation to your neck.
Thyroid nodules: Prevention, early detection, prognosis
To lower your risk of thyroid nodules, make sure you get enough iodine in your diet. The trace element is mainly found in sea fish, but also in algae (sushi) and shellfish. If you use iodized table salt in the kitchen, you are already doing a lot for a healthy iodine supply.
Have your thyroid function checked regularly. For this purpose, the simple blood test is sufficient, and on occasion perhaps an ultrasound examination of the thyroid gland.
If you notice any of the symptoms listed above, be sure to bring them to your doctor’s attention and have the appropriate tests performed. Clarification is important, often it is not something malignant. However, even if it is “only” a hot nodule, a possibly associated hyperthyroidism should be treated.
Course and prognosis in thyroid nodules
If it is a lump that does not lead to pressure complaints, this has no disease value. The unpleasant symptoms of hyperthyroidism caused by a hot nodule can be treated well with appropriate therapy and then disappear. The prognosis for thyroid cancer is also good if detected early.
Thyroid nodules: Treatment depends on the findings
Small nodules that are less than one centimeter in diameter and do not cause discomfort usually do not require treatment. However, even with these thyroid nodules, it is important to check them regularly. This allows changes to be detected at an early stage and counteracted with the appropriate therapy.
For thyroid nodules over one centimeter and those that cause discomfort, treatment depends on what the ultrasound findings look like and whether they are possibly malignant. We will proceed as follows:
- Benign thyroid nodules: Treatment is usually only necessary if the benign nodule measures more than four centimeters or is pressing on the esophagus or trachea or is cosmetically disturbing because it is clearly visible on the outside of the neck, for example. The treatment of choice is then surgery, where the lump is gently removed. In individual cases, radiofrequency ablation may also be considered. In this procedure, the node is sclerosed with heat.
- Hot thyroid nodules: If the nodule is not too large, it can be treated with radioiodine therapy. For this purpose, we administer radioactive iodine with a capsule. The radioactive iodine accumulates in the particularly active thyroid nodule and destroys it. However, if the nodule is very large or if multiple nodules have developed in the thyroid gland, surgery is the treatment of choice. Depending on how extensive the changes are, only part of the thyroid gland is removed, sometimes even the entire gland.
- Thyroid cancer: The primary treatment is surgery, in some forms of this cancer radioiodine therapy is also used afterwards, rarely external radiation or in combination.