Since when has thyroid biopsy been performed?
Needle biopsy, which has been performed since the last half of the 19th century, is a reliable method in the examination of thyroid pathologies. Needle aspiration biopsy of the thyroid gland has been widely practiced since the 1950s. Söderström at Karolinska Hospital in Sweden described thyroid needle biopsy in 1952. Thick needles were used in the first biopsies. With the needle aspiration biopsy technique developed later, histological examination was possible without the need for surgical removal.
Why is thyroid fine needle biopsy performed?
Thyroid Fine Needle Aspiration Biopsy is a method used to investigate the presence of thyroid cancer in thyroid nodules. Thyroid nodules are round or oval masses in the thyroid gland that differ in consistency from their surroundings. Fine needle aspiration biopsy (FNAB) is the most important diagnostic method in the diagnosis of thyroid nodules. Today, this method is considered one of the most effective tests with an accuracy of 95% in distinguishing between benign and malignant thyroid nodules. Nodules can be single or multiple. Nodules are detected in an average of 5 out of 100 people in the community with only examination. This rate is higher in our country. Thyroid nodules can be detected in 5-50 of 100 people with ultrasonography. Thyroid diseases and thyroid nodules are common in our country. Therefore, thyroid fine-needle aspiration biopsy is important to distinguish whether there is cancer in the nodules. Ultrasound-guided thyroid fine-needle aspiration biopsy can be performed even on small nodules (nodules smaller than 10 mm).
How many types of thyroid biopsy methods are there?
Thick needle biopsy method, which was used in the past, is not used much because of the excessive pain, bleeding, and risk of vocal cord (laryngeal) nerve damage. Fine-needle aspiration biopsies with ultrasonography are preferred today. Anesthesia is not required in this procedure, 0.5-1 cm. It can be easily applied to nodules in diameter. If anesthesia is required, 1% lidocaine (xylocaine) can be applied with a 1 ml disposable insulin syringe or local anesthetic creams can be applied half an hour before the procedure. The success of thyroid fine-needle aspiration biopsy in nodules depends on the experience of the person performing it and the location of the nodule.
How is thyroid fine needle aspiration biopsy performed?
The procedure is performed with the patient in the supine position, with the neck thrown back. There is no need for any sedatives or anesthesia before or during the procedure. It is usually done with a 10 cc and 22-23 Gauge disposable syringe, after wiping the skin where the nodule is with alcohol cotton, then inserting a needle into the nodule and trying to get cells. When the needle is inserted into the neck, the patient is asked not to speak or swallow. After the needle is inserted, it is possible to perform aspiration by turning the needle in the nodule and creating pressure with the plunger of the syringe by moving it up and down. More than one needle can be inserted into the same nodule at a time. This biopsy can be repeated at separate times. There is a possibility that not enough cells can be taken from the nodule, and this rate varies between 15-20%. In cases where sufficient cells cannot be obtained, repeat biopsy may be required. During the procedure, there may be pain at the injection site (rarely, it may spread to the jaw and ears and may last for 1-2 days), a small amount of bleeding into the nodule and thyroid, temporary hoarseness, bruising on the skin, swelling in the neck, dizziness, bad feeling, fainting. Bleeding and bruising complications can be seen more frequently in those taking anticoagulant drugs.
Does the presence of a pathologist during fine needle biopsy solve the problem of insufficient material?
In case of inability to get enough fluid to diagnose during aspiration in fine needle biopsies, this rate is 10% even in large centers. During the procedure, if the pathologist immediately looks at the liquid taken under the microscope and is insufficient, a new sample can be taken immediately. Thus, the diagnostic rate can approach 100%. However, it should be known that the diagnosis may not be made due to the structure of some nodules.
Are there any complications caused by thyroid fine needle biopsy?
It has been suggested that the most important complication during the first applications was tumor spread along the tract where the needle was inserted, into the lymph channels and the venous system. However, it has been concluded that this is not clinically significant in hundreds of thousands of needle aspiration biopsies performed. During thyroid biopsy, there may be subcutaneous bleeding and bleeding within the nodule. A slight pain may be felt as a result of a needle prick in the throat during the biopsy. Although rare, swelling and pain in the neck may occur due to bleeding into or out of the nodule. In rare cases, paralysis of the nerves of the vocal cords may develop. The process takes about 5 minutes. There may be a feeling of pain in the throat while swallowing for 24 – 48 hours after the procedure.
What are the conditions that cause misdiagnosis in thyroid fine needle biopsy?
In some cases, biopsy material may be contaminated with blood, fluid and inflammation elements close to the mass. This may cause errors in diagnosis. The tumor has a cystic structure and there may not be enough cells in the cyst fluid for cytological examination.
How many results can be found in the thyroid fine needle aspiration biopsy report?
1. Benign (non-cancerous) nodule: This result is usually indicative of a colloidal nodule, which is obtained in 50-60% of biopsies. When the biopsy is benign, when it is examined by an experienced pathologist in an advanced center, the probability of it turning into cancer is less than 3%. Usually, these nodules do not need to be removed, but if they continue to grow, a new biopsy may be needed in the future.
2. Malignant (cancer) nodule: This result is seen in approximately 5% of biopsies. It indicates papillary cancer, one of the most common thyroid cancers. All of these nodules should preferably be surgically removed by an experienced thyroid surgeon.
3. Suspicious nodule: This result is obtained in about 10% of biopsies or is indicative of a follicular adenoma (non-cancerous) or follicular cancer. Your doctor may want to take a scan to decide which thyroid nodules should be surgically removed.
4. Not diagnostic or insufficient. This result is observed in 20% of biopsies and indicates that a sufficient number of cells cannot be obtained for diagnosis. This is a common result if the nodule is a cyst. These nodules cannot be surgically removed or re-evaluated with a second fine needle biopsy, depending on the clinical decision of the doctor.
