Thyroid nodules are masses of different sizes that form in the thyroid gland and do not resemble normal tissue. While it is 4-7% in countries where iodine deficiency is replaced, such as the USA, this rate is higher in countries with iodine deficiency.
With the use of advanced USG in imaging the thyroid gland, this rate increases to 67%. .
Thyroid nodules are more common in areas of iodine deficiency, in women, in the elderly, and in those exposed to radiation. Thyroid nodules may present visual symptoms in the neck or are detected during a doctor's examination. While some of them grow too much and cause pressure symptoms, many of them are found by chance. Nodules can appear as single nodules or multiple nodules. There are questions that need to be resolved when thyroid nodules are detected. The most important ones:
- Is the nodule benign or malignant?
The rate of malignancy is 5%.
- Does the nodule impair the functions of the thyroid gland?
Overactive (hyperthyroid), underactive (hypothyroid)
<(Shortness of breath, difficulty swallowing, speech disorder…)
Depending on the answers to these questions The patient's treatment protocol varies.
AUXILIARY METHODS USED IN THE DIAGNOSIS OF THYROID NODULES
- History (Anamnesis)
If there are compression symptoms such as progressive difficulty in swallowing, voice disorders and shortness of breath, the possibility of the nodule having a bad character increases. However, it should be kept in mind that these symptoms may also occur in benign nodules. Radiation therapy to the head and neck during childhood or adolescence increases the risk of cancer in thyroid nodules.
The risk of cancer is higher in men, in the child or adolescent age group, in those with nodules under the age of 20 or over the age of 60. Rapid growth of the existing nodule increases the likelihood of cancer. In thyroid nodules, the patient should be investigated for hypothyroidism or hyperthyroidism.
The most important surgical problem in nodules is the possibility of missing thyroid cancer.
- Physical Examination
Manual examination (palpation) of the neck is the easiest and cheapest method to detect thyroid nodules. However, its sensitivity is low. By manual examination, an idea can be made about the size of the thyroid gland, the number, consistency and mobility of the nodule. Nodules that have a hard consistency, do not move, and have irregular edges are more likely to be cancerous. Rarely, nodules may be equally hard when calcified.
During the thyroid manual examination, the entire neck should be evaluated for other masses and lymph nodes. Generally, nodules larger than 1cm can be detected during examination.
- Laboratory Evaluation
Measurement of thyroid hormone levels in the evaluation of nodules is good or bad. It does not distinguish the presence of a benign nodule. TSH should be measured first in the laboratory. If TSH is low, T3 and T4 hormones should be requested. If the TSH level is low, it should be investigated for toxic goiter. If the TSH hormone is high, it should be investigated for Hashimoto's thyroiditis and thyroid antibodies should also be requested. [Antimicrosomal (anti-M) and Antithyroglobin (anti-Tg)] 80-90% antibody is positive in Hashimoto's disease.
Serum calcitonin measurement can be used in thyroid medullary carcinomas.
THYROID NODULES IMAGING
- Thyroid Scintigraphy
Scintigraphy function of the thyroid gland It is an examination that shows this. It is administered to the patient by giving the radioactive substance technetium-99 (Tc99m) or radioactive iodine. According to the status of these radioisotopes, nodules are:
1-) Hypoactive or cold
2-) Normoactive or warm
3-) Nodules are evaluated as hyperactive or hot.
Thyroid scintigraphy is insufficient to distinguish nodules as good or bad. Scintigraphy is used in hyperactive laboratory data.
- Ultrasonography
The rate of its use is increasing in thyroid diseases. It is the most important complement to the physical examination. Nodule, which is found in 4-7% of cases during manual examination, is detected in 50% and above on USG. With USG, the volume, number, dimensions, internal structure, and presence of lymphadenopathy of the nodule can be determined.
USG criteria used in the evaluation of nodules: main criteria such as echogenicity, edge features, presence of halo, small calcifications, blood supply of the nodule, and the relationship of the nodule with neighboring tissues. are themes. At the same time, USG provides great convenience in reaching the target in nodule biopsy and ethanol injection.
- CT and MRI
These imagings show pressure on the trachea. It may be requested in thyroid nodules that form a tumor and have an irregular relationship with the surrounding tissues.
- PET
In recent years, it has begun to be used more in the follow-up of thyroid cancers. .
THYROID FINE NEEDLE ASPIRATION BIOPSY (TINAB)
The most important parameter in the selection of patients requiring surgical treatment is FNAB. In thyroid cancers, its sensitivity is on average 83% (65-98%) and its specificity is 92% (72-100%). The diagnostic accuracy rate is 95%. According to the results of FNAB, the number of patients referred for surgery has decreased. Many unnecessary memories has moved away from literature. However, an average 2-3 fold increase in the number of nodules detected as cancer according to FNAB was detected during surgery. FNAB is a method that can be applied in outpatient clinics, is simple, inexpensive, well tolerated by the patient, and repeatable. It is important to be evaluated by experienced cytopathologists.
70% of the nodules are reported as good, 4% as cancer, 10% as suspicious, and 16% as insufficient material.
Small non-palpable material. (smaller than 1-1.5 cm) FNAB should be performed under USG guidance in cystic and mixed nodules. In cystic and mixed nodules, material should be taken from the cyst wall and the solid part of the nodule. Cystic fluid should be completely aspirated and sent to pathology. In MNG (multinodular goitre) patients with multiple nodules, biopsy can be performed from nodules that meet cancer criteria with USG, but the correct thing is to biopsy each nodule separately.
In thyroid nodules, papillary and medullary biopsy is performed with FNAB and the main diagnosis of plastic cancer can be made. These are follicular neoplasias that are surgically uncertain. After surgery, 20-25% of neoplasias are reported as follicular cancer and 75-80% as benign nodules.
TREATMENT OF THYROID NODULES
Surgical Treatment
- Those with cancer and cancer suspicion as a result of FNAB
- Hyperthyroidism due to large toxic nodule
- Difficulty in swallowing, Compression symptoms such as hoarseness and shortness of breath
- Presence of a nodule over 3cm
- Insufficient material returned despite 3 biopsies
- Although FNAB is benign, there is a risk of cancer If clinical suspicion persists for the disease, surgical treatment is applied to nodules that grow under or without drug therapy.
Thyroid surgery is important in this regard. It should be performed by experienced surgeons.
Medical Treatment
Patients who are followed up by endocrinology specialists are treated according to whether they have a good or bad character, and when necessary, nuclear medicine is applied. We work in coordination with specialists.
Thyroid diseases are a group of diseases that require a multidisciplinary approach such as surgery, endocrinology, nuclear medicine, radiology and pathology. It is a very satisfactory endocrine disorder that is diagnosed with simple methods and treated successfully.
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