Thyroid Fine Needle Aspiration
Reviewed by Andrew J. Bauer, MD
Reviewed on
At the Pediatric Thyroid Center here at Children’s Hospital of Philadelphia (CHOP), our first step to assess children with thyroid nodules is to conduct a thyroid and neck ultrasound. Our radiologists or endocrinologists review the ultrasound images in detail to determine if the thyroid nodule has concerning characteristics and to look for abnormal lymph nodes in the neck.
We collect these images during your child’s visit to our office using a test called a point-of-care ultrasound (POCUS). The advantage of POCUS is that our endocrinologist can review images with you and your child and provide a complete, direct and real-time assessment, right there at your appointment.
POCUS also helps to ensure efficient and accurate decision making if the initial images do not provide complete information to determine whether a nodule should undergo fine needle aspiration biopsy (FNA) or continue to be monitored. We are one of only a few pediatric thyroid clinics in the United States with the ability and expertise to perform and interpret POCUS thyroid and neck ultrasound.
If results show your child needs further testing through a FNA, we will thoroughly explain the process and potential outcomes prior to referring your family to Interventional Radiology, where the procedure is performed.
What is a thyroid fine needle aspiration biopsy?
A thyroid fine needle aspiration (FNA) is a procedure used to determine whether a thyroid nodule is more likely to be cancerous or not cancerous (benign). During FNA, a special clinician called an interventional radiologist uses a very thin needle — skinnier than the needle used for blood draws — to extract a sample of cells from a thyroid nodule or a lymph node.
Thyroid Ultrasound images
What happens during fine needle aspiration?
We have refined the techniques and streamlined the process needed to perform FNA for children and adolescents. We offer all patients sedation to make sure they are comfortable and have less anxiety. This helps us to ensure we obtain an adequate sample. First, the interventional radiologist performs an additional ultrasound to confirm the location and appearance of all thyroid nodules and lymph nodes. The selected thyroid nodules or lymph nodes then undergo FNA.
We perform FNA with ultrasound guidance to make sure we safely collect an accurate sampling. We choose an entry site for the needle, then inject a small amount of local anesthetic to numb your child's skin. The thin needle is carefully moved into the nodule, manipulated to acquire the cells, and then removed. Each nodule may need to be sampled a few times. The FNA procedure takes about one to two hours, with most time spent preparing for it and recovering from sedation.
The doctors who interpret the results of FNA are called cytopathologists. Accurate interpretation is critical to making the best decision for your child. We partner with the Hospital of the University of Pennsylvania (HUP), where their cytopathologists are world renowned for evaluating thyroid cells. We are one of the few pediatric thyroid centers in the country where a cytophathologist is present during FNA, video connected to a microscope in the procedure room. This process is called Rapid On-Site Evaluation (ROSE). The cytopathologist reviews the sampled cells to ensure we obtain an adequate sample and to provide a preliminary interpretation of the result.
For samples with cells that are not clearly benign or cancerous (indeterminate cells), we collect an additional sample from the nodule during the procedure to test things like your child’s DNA and the proteins in their body for diseases or inherited disorders (molecular testing). The molecular test can provide additional information and help determine if your child needs surgery.
We will use the final results of the FNA, provided by the cytopathologist a few days after the procedure, to confirm your child's management plan.
The system used to report results is called The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), a six-tiered scoring system. This system is what your provider will use to review the potential results of your child’s FNA with you.
Does a thyroid fine needle aspiration hurt?
FNA may be painful, depending on the location on your child’s body, and the number of FNA passes required to obtain a sample. Sedation and numbing medicine on your child’s skin helps keep them comfortable.
Most patients who choose to remain awake for the procedure report feeling pressure as we obtain the sample. After the procedure, we cover the injection site with a bandage. Unlike surgical thyroid biopsy, FNA is minimally invasive and does not require stitches or staples. The needle may leave a small bruise, and some patients report mild soreness for one to two days after the procedure.
How soon will I receive the results of a thyroid fine needle aspiration biopsy?
Official results are typically available in five to seven days. When your child’s FNA is scheduled, our team will call you to arrange a follow-up appointment. Your care team may also call you with the results prior to your follow-up appointment.
Can fine needle aspiration be used to treat thyroid nodules?
Certain thyroid nodules may be treated using the FNA technique. These include fluid-filled nodules, called thyroid cysts. In the case of thyroid cysts, we remove the fluid using FNA. Then, we inject sterile, medical-grade alcohol (ethanol) into it. We allow the ethanol to sit for a short period of time, then remove it, so it irritates the lining of the cyst, decreasing the chance for fluid to accumulate again. This procedure is called Percutaneous Ethanol Injection (PEI).
Sometimes, we can treat small lymph nodes (usually less than one centimeter) that contain papillary thyroid cancer with FNA instead of surgery. We do this by gently injecting a tiny amount of ethanol through a fine needle to destroy the cancer cells. This procedure is called ultrasound-guided percutaneous ethanol ablation (EA). The ethanol stays in the lymph node to do its work, and for many patients, this can be done instead of another surgery or radioactive iodine treatment. Some children may need two or more injections, spaced six to 12 months apart. If we think this treatment could help your child, your Thyroid Center doctor and our interventional radiologist will take time to explain the procedure and answer all your questions.
Why choose CHOP for thyroid fine needle aspiration
Here at CHOP, we have completed around 50 thyroid needle aspirations per year (more than 728 patients) for the past 14 years. Over this entire time, fewer than than 2% of patients who have undergone FNA of a thyroid nodule have gotten results that did not provide enough information, requiring the test to be done again.
| Non-diagnostic | Benign | Follicular Lesion of Undetermined Significance (FLUS) | Follicular neoplasm | Suspicious / Malignant | TOTAL | |
|---|---|---|---|---|---|---|
| 2010 | 3 | 10 | 5 | 3 | 3 | 24 |
| 2011 | 3 | 22 | 2 | 8 | 9 | 44 |
| 2012 | 0 | 31 | 2 | 3 | 8 | 44 |
| 2013 | 0 | 23 | 7 | 5 | 9 | 44 |
| 2014 | 0 | 26 | 6 | 5 | 16 | 53 |
| 2015 | 0 | 36 | 3 | 4 | 11 | 54 |
| 2016 | 0 | 45 | 6 | 4 | 15 | 70 |
| 2017 | 2 | 29 | 7 | 3 | 18 | 59 |
| 2018 | 1 | 22 | 5 | 4 | 22 | 54 |
| 2019 | 1 | 13 | 15 | 6 | 20 | 55 |
| 2020 | 0 | 13 | 9 | 4 | 13 | 39 |
| 2021 | 2 | 12 | 11 | 4 | 24 | 53 |
| 2022 | 3 | 16 | 6 | 4 | 16 | 45 |
| 2023 | 1 | 10 | 6 | 6 | 24 | 47 |
| 2024 | 0 | 10 | 11 | 5 | 17 | 43 |
Using ROSE along with conscious sedation has decreased the number of passes required per nodule. As a result, very few patients require a repeat FNA because the test did not provide enough information. Also, our careful pre-surgery evaluation is accurate and reliable. It helps us plan the right amount of surgery for each patient, which lowers the chances of needing a second operation.
We are currently working with our radiology artificial intelligence (AI) team to find ways to identify thyroid nodules that are more likely to spread to lymph nodes in the neck (lateral neck lymph node metastasis).