What is a thyroid nodule?
Thyroid nodules are found in the in the thyroid as abnormal masses of different sizes that do not resemble the thyroid tissue. Thyroid nodules are common in the population. With the widespread use of ultrasonography, their incidence has reached rates of up to 30-50%. The incidence of thyroid nodules in women increases further with advancing age, radiation exposure, and iodine deficiency.
Besides it is a common disease, it is critical to diagnose and treat nodules that may be cancerous. It is becoming increasingly important for physicians to avoid unnecessary surgery in benign nodules or not to miss the diagnosis of malignancy.
Which Complaints (Symptoms) Develop In Thyroid Nodules?
Thyroid nodules usually do not cause complaints in patients. They are usually identified during a doctor’s manual examination and during ultrasound imaging. Some patients may present with a swelling in the neck. Rarely; large nodules may cause difficulty in swallowing, shortness of breath, and hoarseness, referred to as compression symptoms. In patients with thyroid nodules, thyroid hormones are usually normal.
How Are Thyroid Nodules Followed up And How Are They Treated (Operated)?
When a thyroid nodule is identified, the aim is to find out whether the nodule is benign or malignant. Also, the hormonal status of the thyroid nodule should be determined. Another question to be answered is whether the nodule creates any compression complaints.
Although the thyroid gland works normally in the majority of thyroid disease patients, it is useful to test the thyroid hormone levels to determine whether the gland works more (hyperthyroidism) or less (hypothyroidism) than normal.
In a patient with thyroid nodules, one of the other primary tests is an ultrasound examination. First of all, it should be determined whether the palpable abnormality is actually a nodule. When the decision is made to follow up the nodule, prospective ultrasound examinations will allow physicians to follow up the changes in the size of the nodule. Ultrasonography is very useful in detecting the number and size of the nodules and helpful in identifying cancerous nodules. Also, an ultrasound-guided needle biopsy can be performed, allowing for the collection of tissue samples from considerably small nodules. Another characteristic finding than can be visualized in ultrasonography is regional lymphadenomegaly.
The guidelines recommend performing a fine needle aspiration biopsy after determining TSH levels and ultrasonography. Needle biopsy is the diagnostic method that provides the most accurate evaluation of the structure of thyroid nodules. Ultrasound-guided needle biopsies reduced the rate of imprecise findings leading to a misdiagnosis. Needle biopsy is a very important diagnostic method in making the diagnosis. It is performed using the needle of a syringe in office conditions. After the procedure, the patient can go home. The cells collected with the use of the needle are spread over a glass and submitted to the laboratory for further examination. In the hands of an experienced cytologist, the diagnostic accuracy rate is 95-98%. The findings of the examination are reported under five categories as benign, malignant, suspicious, inadequate material, and atypia of undetermined significance.
In summary, the diagnostic approach in a patient with a thyroid nodule can be listed as follows:
1. Clinical Assessment
2. Assessment of TSH levels and ultrasonographic evaluation
3.FNAB (Fine Needle Aspiration Biopsy)
Needle biopsy is indicated in patients having no identified risk factors based on anamnesis and physical examination findings. It is not necessary either for nodules with a diameter of <1 cm as determined in USG and for patients with no suspicious findings in USG. These patients are followed up at annual visits. Drug therapy is not recommended for benign thyroid nodules. Treatment is not indicated for benign thyroid nodules when they do not cause compression symptoms and the hormone levels are normal. Although needle biopsy results are reported benign, surgery may sometimes be indicated due to cosmetic reasons, compression symptoms (hoarseness and difficulty in swallowing, etc.), the growth of the benign nodules in the follow-up period, and patients’ preference. When the cytological test results suggest malignancy, the treatment of choice is almost always surgery. It is commonly accepted that; when cytological findings suggest suspicions and when malignancy cannot be completely excluded, surgery is indicated for the management of nodules.
However, there is no consensus on the treatment methods for the nodules identified as having atypia of undetermined significance. An FNAB biopsy sample can be taken and examined again in the following 3-6 months before deciding whether to proceed with follow-up or surgery for nodules diagnosed with atypia of undetermined significance. When similar results are reported in repeat samples, the decision is made based on the risk factors.
Which Nodules Have a High Cancer Risk?
Approximately 50% of solitary nodules in children under 14 years of age are thyroid cancers. A previous exposure to radiotherapy in the neck increases the likelihood of developing cancer in these patients. Advancing age increases the risk of cancer. Although multinodular goiter is more common in women, men have a higher risk of cancer in solitary nodules. Some clinical features should be investigated in patients with thyroid nodules. Cancer should be suspected in patients with rapidly growing hard and adherent tissue and palpable ganglions in the neck. It should also be suspected in patients with thyroid nodules and a history of receiving irradiation to the head, neck, and chest. Hoarseness accompanying thyroid nodules should suggest cancer, too.