What is a thyroid nodule?
Thyroid nodule; It is the name given to the spherical or oval-shaped tissue that occupies a prominent place in the thyroid gland, differs in consistency from the surrounding normal thyroid tissue. A nodule may be called a mass or lump within the thyroid gland that should not normally be present. In the presence of nodules in the thyroid gland, the disease is called nodular goiter. Thyroid nodules can vary in size from a few millimeters to several centimeters. Thyroid nodule constitutes the most common thyroid gland disease group in the community.
Why do thyroid nodules occur?
The most important factor in the formation of thyroid nodules is iodine deficiency. The incidence of thyroid nodules has increased significantly in iodine-deficient regions such as our country. Nodular goiter has been detected in nearly half of the adult population in ultrasound scans performed throughout Turkey. Apart from iodine deficiency, some environmental factors such as natural goitrogens are also important in the development of thyroid nodules. We also know that some genetic (familial) factors are also important in the formation of thyroid nodules.
What are the symptoms of thyroid nodules?
Most patients with nodular goiter often have no complaints. In most patients, nodules are detected during the visit to the doctor for other reasons. It is found incidentally on physical examination or imaging performed for non-thyroid causes.
The nodule in the thyroid gland is often not noticed from the outside. Few patients apply to the doctor because of the swelling they or the people around them notice on their neck. In addition, rarely, patients may consult a doctor due to complaints of excessive hormone secretion from the nodule (hyperthyroidism). In very few cases, a physician is consulted due to complaints of compression on surrounding structures. In rare cases, if bleeding into the nodule occurs, there may be a complaint of pain in the neck. In patients who were found to have a nodule incidentally, “I don’t have a goiter complaint. Therefore, there is no need for further investigation.” That thought is completely wrong. There are similar risks in these patients as in the patients presenting with the complaint of nodules.
What are the risks of a thyroid nodule?
Thyroid nodule has 4 main risks for the patient. These can be listed as follows:
- The most important risk associated with thyroid nodules; There is a risk of thyroid cancer in 5 percent of nodules in the thyroid gland. Therefore, the most important and primary evaluation in a patient with a thyroid nodule is to exclude the risk of thyroid cancer in the nodule. There may be one or more nodules (multiple) in the thyroid gland. Contrary to the general belief, the fact that the nodule is single or multiple does not significantly change the cancer risk of the nodule. The generally accepted view is that each nodule in the gland has the same cancer risk.
- Especially large nodules may compress the surrounding structures depending on the location of the nodule in the thyroid gland. Pressure on the trachea can cause shortness of breath, pressure on the esophagus can cause difficulty in swallowing, and pressure on vocal nerves can cause hoarseness and thickening of the voice. Compression nodules are often over 4 cm. Small nodules are not expected to cause compression.
- One or more of the existing nodules in the thyroid gland may cause excessive thyroid hormone secretion, causing toxic goiter (hyperthyroidism). These types of nodules are called hot nodules, toxic nodules, autonomous nodules, and hyperactive nodules.
- The existing thyroid nodule may cause problems for the patient in terms of aesthetic appearance on the neck due to its size.
What are the types of thyroid nodules?
Nodules in the thyroid gland can be grouped under three main headings according to their structures:
- Nodules of solid consistency (solid)
- Mixed nodules of semi-solid-liquid consistency (semi-solid)
- Fluid (cystic) nodules/simple thyroid cysts
What are the diagnostic methods of thyroid nodules?
First of all, a physical examination and blood test are done by hand. The nodules are then examined by ultrasound. In addition, nodules in ultrasound examination, according to ultrasound images; It can be defined as hypoechoic, isoechoic, mixed and cystic nodules. Nodules according to their thyroid scintigraphic appearance; Also called cold nodules, hot nodules and warm nodules.
In cases such as Hashimoto’s and Graves’ disease, there may be a granular, coarse appearance in the structure of the gland due to the chronic inflammatory process on thyroid ultrasound. This structure may give the appearance of a false nodule (pseudo-nodule) as if there is a nodule in the gland in the ultrasound view. If thyroid ultrasound is not performed by an experienced person, the pseudo-nodule image of chronic thyroiditis in the thyroid gland may be deceptive.
Nodular goiter patients with normal thyroid function tests often do not need scintigraphic examination. Scintigraphic examination is often performed on patients with excess hormone (hyperthyroidism) in thyroid function tests.
The most important step in the evaluation of thyroid nodules is to exclude the possibility of cancer of the thyroid nodule. It is not appropriate to evaluate that a nodule is benign by methods such as ultrasound or scintigraphy without a fine needle aspiration biopsy. Since it is generally known that approximately 5 percent of thyroid gland nodules are cancer, all patients with a nodule size of 10 mm and above should undergo biopsy. Smaller nodules can also be biopsied in suspected patients.
What are the cases where the suspicion of cancer in the thyroid nodule increases?
In the nodule in the thyroid gland;
- rapid size increase,
- Swelling in the lymph nodes in the neck area,
- Nodule that is very hard and adhered to the surrounding tissues,
- Thyroid cancer should be suspected in cases of hoarseness or thickening of the voice.
Thyroid cancer risk;
- exposed to radiation,
- Radiotherapy applied to the neck area,
- Having a family history of thyroid cancer
- It increases in patients younger than 20 years old or over 70 years old.
How is a thyroid nodule treated?
The pathology result of the fine needle aspiration biopsy performed from the nodule is of great importance in terms of how to treat the thyroid nodule.
In the presence of hyperthyroidism (toxic nodule), radioactive iodine therapy may be a good treatment alternative. In today’s conditions, radioactive iodine treatment is a treatment alternative that will be preferred more frequently in many patients compared to surgery. In such a case, it would be appropriate for the patient to discuss this treatment alternative with his physician.
It is sufficient to follow only benign nodules that are not cancerous. A nodule confirmed to be benign by thyroid fine-needle aspiration biopsy should be followed up with thyroid ultrasound at 6-24 month intervals depending on the risk in ultrasonography. If an enlarged thyroid nodule is detected, a repeat biopsy may be required. Sometimes, even if the biopsy result is benign, surgery can be performed in cases where the nodule continues to grow and/or clinical suspicion of cancer is increased. In addition, surgical intervention can be performed in patients with multiple nodules (multinodular goiter) in the thyroid gland, in whom biopsy is not possible, or in patients with retrosternal nodular goiter that extends into the thorax.
In previous years, thyroid hormone suppression therapy to shrink thyroid nodules was a frequently used method by physicians. However, in recent studies, it has been reported that suppression therapy is not very effective. In addition, it was determined that thyroid hormone suppression therapy had a negative effect on bone structure, especially in postmenopausal female patients, and it was determined that it caused heart rhythm problems. For this reason, suppression treatment with thyroid hormone is no longer preferred in patients with nodular goiter. Although it is not widely used, there are applications such as radioactive iodine therapy, alcohol injections into the nodule, laser therapy, high-intensity focused ultrasonic sound wave therapy and radiofrequency ablation therapy in selected patients with nodular goiter, and good results are obtained in selected cases.
