INTRODUCTION Thyroid Bethesda Reporting System is a six-tiered system that aims to bring uniformity in reporting thyroid cytology and improve the communication with clinicians. The system has achieved its goal as a presurgical diagnostic method; however, it remains a screening method in the grey zone categories, namely atypia of undetermined significance (AUS) and follicular neoplasm (FN). The book recently released the 3rd edition, following the recent changes in thyroid pathology. One of the most important novelties is subgrouping AUS category and FN to be able to make a better risk stratification in these categories. Our group aims to retrospectively analyze a large dataset based on the new TBSRTC, with a focus on the grey zone categories. METHODS Only patients who underwent lobectomy or total thyroidectomy were included, allowing for direct comparison between cytological and histopathological results. Cytological evaluations, based on the TBSRTC 3rd edition, were methodically compared with their respective histopathological results, enabling a comprehensive analysis. RESULTS Of the 244 patients (Female:Male ratio = 8.8:1, Mean age = 56), a total of 252 nodules were evaluated. A distinction was noted with 79 nodules (31%) diagnosed as AUS and 173 nodules (69%) as FN. Intriguingly, the ROM for AUS-overall stood at 44.3%, with AUS-nuclear atypia at 50% and AUS-other at 43.2%. Although the AUS sub-divisions did not demonstrate statistical significance, a significant disparity was observed in their distribution, with 15% as AUS-nuclear atypia compared to 85% as AUS-other. This disparity raises the question: Could AUS-other be considered the new waste-basket category in the TBSRTC 3rd edition? Using the TBSRTC 3rd edition as a base, we added a subclassification for FN nodules based on the presence or absence of PTC nuclear features. Our findings showed that differentiating FN with oncocytic characteristics correlated well with histological outcomes and ROMs. Though retrospective in design with inherent bias potential, our data suggests a possible improvement in PTC case segregation in the FN category when differentiating between FN nodules with and without PTC nuclear features. CONCLUSION Our retrospective study sheds light on the potential advantages of the TBSRTC 3rd edition, particularly in refining the AUS and FN categories for thyroid nodules. The clear disparity in AUS sub-categories raises important questions about their classification and potential future refinements. Moreover, the differentiation of FN nodules based on PTC nuclear features holds a promising approach for better risk stratification.

中文翻译：

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第三版贝塞斯达甲状腺细胞病理学报告系统对灰色区域类别的影响。

简介 甲状腺 Bethesda 报告系统是一个六层系统，旨在实现甲状腺细胞学报告的统一并改善与临床医生的沟通。该系统已经实现了作为术前诊断方法的目标；然而，它仍然是灰色地带类别的筛查方法，即意义未明的异型性（AUS）和滤泡性肿瘤（FN）。该书最近发布了第三版，紧随甲状腺病理学的最新变化。最重要的创新之一是将 AUS 类别和 FN 进行分组，以便能够在这些类别中进行更好的风险分层。我们小组的目标是回顾性分析基于新 TBSRTC 的大型数据集，重点关注灰色区域类别。方法 仅纳入接受肺叶切除术或甲状腺全切除术的患者，以便直接比较细胞学和组织病理学结果。基于 TBSRTC 第 3 版的细胞学评估与各自的组织病理学结果进行了系统比较，从而实现了全面分析。结果 244 名患者（女性：男性比例 = 8.8：1，平均年龄 = 56）中，总共评估了 252 个结节。值得注意的是，79 个结节 (31%) 被诊断为 AUS，173 个结节 (69%) 被诊断为 FN。有趣的是，AUS 总体的 ROM 为 44.3%，AUS 核异型性为 50%，AUS 其他为 43.2%。尽管 AUS 细分没有表现出统计显着性，但在其分布中观察到显着差异，其中 15% 为 AUS 核异型性，而 85% 为 AUS-其他。这种差异提出了一个问题：澳大利亚-其他国家是否可以被视为 TBSRTC 第 3 版中新的废纸篓类别？以 TBSRTC 第 3 版为基础，我们根据是否存在 PTC 核特征添加了 FN 结节的子分类。我们的研究结果表明，区分 FN 与嗜酸细胞特征与组织学结果和 ROM 密切相关。尽管回顾性设计具有潜在的潜在偏差，但我们的数据表明，在区分具有和不具有 PTC 核特征的 FN 结节时，FN 类别中 PTC 病例的分离可能会有所改善。结论 我们的回顾性研究揭示了 TBSRTC 第三版的潜在优势，特别是在完善甲状腺结节的 AUS 和 FN 类别方面。AUS 子类别之间的明显差异引发了有关其分类和未来潜在改进的重要问题。此外，基于 PTC 核特征的 FN 结节分化为更好的风险分层提供了一种有前景的方法。