WHAT IS A THYROOD NODULE?
Thyroid nodules are cystic (fluid-filled) or solid (solid, non-liquid) masses in the thyroid gland that are formed as a result of excessive proliferation of the cells that make up the gland. Although the vast majority of thyroid nodules are benign (non-cancerous), a small proportion involve thyroid cancer. Most thyroid nodules need to be evaluated to diagnose and treat thyroid cancer at the earliest stage.
WHY DOES A THYROID NODULE OCCUR?
The cause of a thyroid nodule is generally unknown. Hashimoto's thyroiditis, the most common cause of hypothyroidism, can cause a thyroid nodule. It is known that iodine deficiency, which is common in our country, causes thyroid nodules. Some nodules may gain autonomy over time and secrete excessive amounts of thyroid hormone, causing hyperthyroidism (toxic adenoma, hyperfunctional thyroid nodule as in toxic multinodular goiter).
Thyroid nodules are common lesions. A thyroid nodule is detected by examination or imaging in about half of people who reach the age of 60 in the community. More than 90% of these nodules are benign. The majority are found as colloidal nodules, thyroid cysts or follicular neoplasms, less than 10% of the nodules may also be due to thyroid cancer. . Rarely, they may cause symptoms of pain, difficulty swallowing, shortness of breath, hoarseness, or hyperthyroidism.
HOW TO DETECT AND EVALUATE A THYROID NODULE? It is detected incidentally during neck ultrasound or tomography. Sometimes, patients find thyroid nodules themselves when looking in the mirror, noticing a lump on their neck by accident. must be determined. For this purpose, thyroid function tests should be checked. In addition, thyroid ultrasonography and fine needle biopsy should also be performed for more detailed evaluation.
THYROID ULT RASONU
Thyroid ultrasound is an important imaging method for thyroid nodule evaluation. High-frequency sound waves are used to obtain an image of the thyroid. Thyroid ultrasound can determine whether the nodule is solid or cystic (fluid-filled), as well as determine the exact size and characteristics of the nodule. Thus, it can help identify suspicious nodules for cancer. Thyroid ultrasound can also detect nodules that are too small to be felt during physical examination, thus determining the actual number of nodules. After the initial evaluation is completed, thyroid ultrasound is also useful in determining changes in size and characteristics in the follow-up of nodules.
In addition, ultrasound can be used to perform fine needle biopsy when required.
THYROID FINE NEEDLE ASPIRATION BIOPSY (TIIAB)
>It is a simple procedure that can be performed even without the need for local anesthesia. Usually, it does not require any special preparation, only if there is the use of blood thinners, it may need to be discontinued a few days before the procedure.
A very fine needle is used to draw the cells in the thyroid nodule while performing TIAB, and several samples are taken from different parts of the nodule to increase the chance of getting the most accurate result. The cells are then examined under a microscope by a pathologist.
Thyroid fine needle aspiration biopsy results may be reported as follows:
The nodule is benign (not cancerous).
About 80% of biopsies are these way. Its false negative rate is less than 3%. Benign thyroid nodules do not require surgery unless they cause symptoms such as shortness of breath or difficulty swallowing. It is enough to follow. If the nodule enlarges over time or changes in its characteristics, it may be necessary to repeat the biopsy.
The nodule is malignant (cancer) or suspicious for malignancy (cancer). It is caused by the common type of papillary cancer. A suspicious nodule for malignancy carries a 60-75% cancer risk. Nodules with both these diagnoses should be surgically removed.
The structure of the nodule could not be determined (uncertain).
This expression, which can be seen in the section, may indicate several different diagnoses. The definition of “uncertain” means that although a sufficient number of cells are removed during fine needle biopsy, microscopic examination cannot reliably classify the result as benign or cancer. Approximately 20-30% of nodules reported as follicular lesions are cancerous. Definitive diagnosis can only be made by surgery. In this case, since the nodule is more likely to be non-cancerous (70-80%), usually only one side of the thyroid, where the nodule is located, is removed (lobectomy). If cancer is detected, the remaining thyroid gland should usually be removed as well. If it is confirmed by surgery that there is no cancer, no additional surgery is required to “complete” the surgery to remove the remaining thyroid. Lesion of Undetermined Significance = FLUS). Cells in this nodule are defined as indeterminate because they lack characteristics that would place them in one of the other diagnostic categories. They rarely contain cancer, so they need to be re-evaluated with FNAB, in which case another option may be surgery to remove half of the thyroid containing the nodule (lobectomy).
The biopsy may be non-diagnostic or insufficient.
reported in less than 5% of biopsies when performed under ultrasound guidance. This result indicates that not enough cells are obtained to make a diagnosis, but it is common if the nodule is a cyst. These nodules may need to be re-evaluated with a second fine needle biopsy.
THYROID Scintigraphies
Thyroid scintigraphies have been used very frequently in the past to evaluate thyroid nodules. However, thyroid scintigraphy is no longer accepted as a first-line evaluation method with the demonstration of the very high accuracy and sensitivity of thyroid ultrasound and TIAP.
Scintigraphy still has an important role in the evaluation of nodules that cause hyperthyroidism. what Scintigraphy of nodules causing perthyroidism may support the need for additional evaluation or biopsy. In many other cases, neck ultrasound and FNAB remain the best and most accurate way to evaluate any type of thyroid nodule.
MOLECULAR TESTS
Newly developed molecular studies examining genes in the DNA of thyroid nodules There are tests and they continue to be developed in a dynamic process. These tests can be useful in determining whether the nodule is cancerous, especially in cases where the FNAB result is uncertain. These special tests are done on samples taken during the normal biopsy procedure. There are also special blood tests that can help evaluate thyroid nodules. However, there are some difficulties in reaching and having these. Preventive (prophylactic) mastectomy can significantly reduce the risk of developing breast cancer, but it should be noted that this surgery is also a serious choice that can have a significant impact on your future life. Preventive mastectomy is performed on one or both breasts to reduce the risk of developing breast cancer.
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