Department of Radiology and Center for Imaging Science, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Korean J Radiol. 2023 Sep;24(9):903-911. doi: 10.3348/kjr.2023.0386.
Regrowth after radiofrequency ablation (RFA) of symptomatic large thyroid nodules, initially treated as benign, sometimes turns out to be malignancies. This study aimed to assess the ultrasound (US) characteristics of thyroid nodules initially treated as benign with RFA and later diagnosed as cancers, predictive factors for cancers masquerading as benign, and methods to avoid RFA in these cancers.
We reviewed the medical records of 134 consecutive patients with 148 nodules who underwent RFA between February 2008 and November 2016 for the debulking of symptomatic thyroid nodules diagnosed as benign using US-guided biopsy. We investigated the pre-RFA characteristics of the thyroid nodules, changes at follow-up after RFA, and the final surgical pathology.
Nodule regrowth after RFA was observed in 36 (24.3%) of the 148 benign nodules. Twenty-two of the 36 nodules were surgically removed, and malignancies were confirmed in seven (19.4% of 36). Of the 22 nodules removed surgically, pre-RFA median volume (range) was significantly larger for malignant nodules than for benign nodules: 22.4 (13.9-84.5) vs. 13.4 (7.3-16.8) mL ( = 0.04). There was no significant difference in the regrowth interval between benign and malignant nodules ( = 0.49). The median volume reduction rate (range) at 12 months was significantly lower for malignant nodules than for benign nodules (51.4% [0-57.8] vs. 83.8% [47.9-89.6]) ( = 0.01). The pre-RFA benignity of all seven malignant nodules was confirmed using two US-guided fine-needle aspirations (FNAs), except for one nodule, which was confirmed using US-guided core-needle biopsy (CNB). Regrown malignant nodules were diagnosed as suspicious follicular neoplasms by CNB. Histological examination of the malignant nodules revealed follicular thyroid carcinomas, except for one follicular variant, a papillary thyroid carcinoma.
Symptomatic large benign thyroid nodules showing regrowth or suboptimal reduction after RFA may have malignant potential. The confirmation of these nodules is better with CNB than with FNA.
射频消融（RFA）治疗后，最初被诊断为良性的有症状的大甲状腺结节会出现复发，其中有些结节最终被诊断为恶性肿瘤。本研究旨在评估经 RFA 治疗的最初被诊断为良性、但后来被诊断为癌症的甲状腺结节的超声（US）特征、表现为良性的癌症的预测因素，以及避免对这些癌症进行 RFA 的方法。
我们回顾了 2008 年 2 月至 2016 年 11 月期间因超声引导下活检诊断为良性的有症状甲状腺结节而接受 RFA 减瘤治疗的 134 例连续患者的病历资料，共 148 个结节。我们研究了 RFA 前甲状腺结节的特征、RFA 后随访时的变化，以及最终的手术病理。
在 148 个良性结节中，有 36 个（24.3%）在 RFA 后出现结节复发。36 个结节中有 22 个进行了手术切除，其中 7 个（36 个的 19.4%）被证实为恶性肿瘤。在 22 个手术切除的结节中，恶性结节的 RFA 前中位体积（范围）明显大于良性结节：22.4（13.9-84.5）与 13.4（7.3-16.8）mL（ = 0.04）。良性和恶性结节的复发间隔无显著差异（ = 0.49）。12 个月时，恶性结节的中位体积减少率（范围）明显低于良性结节（51.4%[0-57.8]与 83.8%[47.9-89.6]）（ = 0.01）。除 1 个结节外，其余 7 个恶性结节的术前均经两次超声引导下细针抽吸活检（FNA）证实为良性，该结节经超声引导下核心针活检（CNB）证实为良性。复发性恶性结节经 CNB 诊断为可疑滤泡性肿瘤。对恶性结节的组织学检查显示，除 1 例为甲状腺滤泡癌的滤泡变异型外，其余均为甲状腺滤泡癌。
射频消融（RFA）治疗后出现复发或效果不佳的有症状大良性甲状腺结节可能具有恶性潜能。这些结节采用 CNB 诊断优于 FNA。
