High-grade Thyroid Cancer Diagnosed After Radiofrequency Ablation Therapy With Multiple Benign Biopsies

Q: Why are two benign FNAs recommended before thyroid radiofrequency ablation?

Two fine-needle aspirations (FNAs) prior to radiofrequency ablation (RFA) are recommended to rule out malignancy in thyroid nodules, particularly within specified TI-RADS categories.

Q: What did the patient’s FNAs show before undergoing RFA?

The patient underwent FNA twice, separated by months, and both procedures showed benign cytology with oncocytic features and abundant colloid.

Q: What led to surgery after RFA and what was found on pathology?

Compressive symptoms recurred about 6 months after RFA, and follow-up ultrasound 13 months post-RFA showed nodule enlargement. Right hemithyroidectomy and subsequent completion thyroidectomy were performed, and pathology revealed a differentiated high-grade thyroid carcinoma with extensive angioinvasion.

Sep 30, 2026

Uploaded by Adam

Radiofrequency ablation (RFA) reduces symptomatic thyroid nodule size, and two benign fine-needle aspirations (FNA) are recommended before RFA to rule out malignancy. This case describes subsequent surgical pathology revealing high-grade thyroid cancer despite two benign FNAs. A 31-year-old woman with an ACR-TI-RADS 3 nodule chose RFA; benign cytology was obtained twice. After recurrent compressive symptoms, follow-up ultrasound showed growth and continued TI-RADS 3 classification, leading to hemithyroidectomy and completion thyroidectomy.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Abstract

Introduction

Case Presentation

Diagnostic Assessment

Treatment

Outcome and Follow-up

High-grade Thyroid Cancer Diagnosed After Radiofrequency Ablation Therapy With Multiple Benign Biopsies Mayumi Endo, 1 Isaye Barton, 1 Nicole Zern,2 James Y. Lim,3 Tracy S. Tylee, 1 and Mara Y. Roth 1 1 Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, WA 98195, USA 2 Department of Surgery, Valley Medical Center, Renton, WA 98055, USA 3 Division of Surgical Oncology, Department of Surgery, Oregon Health & Science University, Portland, OR 97239, USA Correspondence: Mayumi Endo, MD, ECNU, Division of Metabolism, Endocrinology, and Nutrition, University of Washington, 4245 Roosevelt Way NE, Box 356426, Seattle, WA 98195, [USA. Email:](USA. Email: mayendo@uw.edu)[ mayendo@uw.edu](USA. Email: mayendo@uw.edu). Abstract Radiofrequency ablation (RFA) reduces the size of symptomatic thyroid nodules. Two benign fine needle aspirations (FNA) prior to RFA are recommended to rule out malignancy. Here we present a case of high-grade thyroid cancer found on subsequent surgical pathology despite 2 benign FNAs prior to RFA. A 31-year-old female presented with 5.5 cm American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TI-RADS) 3 nodule. Her family history and radiation exposure were negative. She opted for RFA and underwent FNA twice, which was benign. Her compressive symptoms recurred in 6 months. Ultrasound 13 months post-RFA demonstrated enlargement of the nodule to 6.0 cm, representing a 26% growth from the original size before therapy. The nodule remained at TI-RADS 3 based on ultrasound. Due to her compressive symptoms, she underwent a right hemithyroidectomy. Pathology showed a 6.5 cm differentiated high-grade thyroid carcinoma with oncocytic features, tumor necrosis, and extensive angioinvasion (pT3aN0a) . She underwent completion thyroidectomy followed by radioactive iodine therapy (RAI) . She achieved no evidence of disease status with undetectable thyroglobulin 9 months after the RAI. Ongoing follow-up after RFA is important to monitor for nodule regrowth and to recognize potential malignancy. Key Words: radiofrequency ablation therapy, thyroid cancer Introduction Radiofrequency ablation of the thyroid is an effective noninvasive procedure to treat symptomatic thyroid nodules with minimal complication rates. Its use has been recommended in symptomatic benign nodules and toxic nodules [1-3] . For nonfunctional thyroid nodules, the current recommendations are for 2 fine-needle aspirations (FNAs) prior to radiofrequency ablation (RFA) to rule out malignancy in American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TI-RADS) category 3 to 5 [1-4] . The risk of malignancy after 2 benign FNAs has been shown tobe <3%[5]. Here we present a case of angioinvasive oncocytic high-grade thyroid cancer diagnosed after RFA on surgical pathology despite 2 benign FNAs prior to RFA. Case Presentation A 31-year-old female first presented with a large thyroid nodule in 2019. Initial thyroid ultrasound demonstrated a 5.0 × 4.0 × 5.5 cm ACR TI-RADS 3 nodule in the right isthmus. TSH was 1.5 µIU/mL (SI: 1.5 mIU/L) (reference range, 0.400-5.000 µIU/mL [SI: 0.400-5.000 mIU/L]) . She had no family history of thyroid disease or thyroid cancer or history of radiation exposure. Diagnostic Assessment She underwent FNA twice separated by 5 months, which both showed benign cytology (Fig. 1) . All cytology specimens were interpreted by pathologists specializing in head and neck cancer at a tertiary academic center. Treatment Due to compressive symptoms, she explored the options of a therapeutic lobectomy vs RFA and chose to undergo RFA of the nodule, at that point, measuring 5.1 × 3.8 × 5.6 cm in March 2022. The preprocedural ultrasound imaging is shown in Fig. 2. Her symptoms improved for approximately 6 months, although she did not return for recommended follow-up ultrasounds. Outcome and Follow-up She developed recurrent compressive symptoms ar

FAQs

Why are two benign FNAs recommended before thyroid radiofrequency ablation?

Two fine-needle aspirations (FNAs) prior to radiofrequency ablation (RFA) are recommended to rule out malignancy in thyroid nodules, particularly within specified TI-RADS categories.

What did the patient’s FNAs show before undergoing RFA?

The patient underwent FNA twice, separated by months, and both procedures showed benign cytology with oncocytic features and abundant colloid.

What led to surgery after RFA and what was found on pathology?

Compressive symptoms recurred about 6 months after RFA, and follow-up ultrasound 13 months post-RFA showed nodule enlargement. Right hemithyroidectomy and subsequent completion thyroidectomy were performed, and pathology revealed a differentiated high-grade thyroid carcinoma with extensive angioinvasion.

Sep 30, 2026

Uploaded by Adam