Pagni F, Prada M, Goffredo P, Isimbaldi G, Crippa S, Di Bella C, Leone B E
Department of Pathology, San Gerardo Hospital, University Milan Bicocca, Monza, Italy.
Cytopathology. 2014 Jun;25(3):170-6. doi: 10.1111/cyt.12085. Epub 2013 Aug 12.
The British system (Thy1-5), the Bethesda system for reporting thyroid cytopathology (BSRTC) and the Italian Society of Anatomic Pathology and Cytology (SIAPEC) classification represent the most important international classifications for thyroid cytopathology. Irrespective of the system used, the 'indeterminate' categories are still debated among cytopathologists, particularly with regard to diagnostic criteria, clinical impact of subclassification and role of molecular techniques.
We aimed to find answers to the following questions: Are there shared criteria in cytological preparations that allow the division of indeterminate follicular lesions into subcategories? What is the true clinical impact of this possible subclassification?
Among 1150 consecutive thyroid fine needle aspiration (FNA) specimens, 80 patients had nodules with a final cytological report of Tir3 (SIAPEC)/Thy3. These 80 cases were re-evaluated and subclassified according to morphological criteria into three groups: pure follicular proliferations, Hürthle cell follicular lesions and atypical proliferations.
Sixteen (20%) cases were categorized as pure follicular proliferations, 40 (50%) as Hürthle cell follicular lesions and 24 (30%) as atypical proliferations. Surgery was performed in 57 cases (71%). Cyto-histological correlation showed that follicular adenoma was the most frequent final diagnosis in the cases treated by surgery (24/57, 42%). The overall malignancy rate in the Tir3 category was 28% (16/57). Atypical proliferations were more often malignant than either of the follicular groups (53% versus 19%, P = 0.019).
A five-tiered classification, subdividing the 'indeterminate for malignancy' class into 'follicular proliferations' and 'atypical lesions' could be adopted. As a result of their higher risk of malignancy, surgical management of the atypical lesions would be justified. In future, the introduction of a genetic panel might contribute to their stratification, to the determination of a more accurate risk of malignancy of the atypical lesions and to the verification of follicular proliferations that are benign.
英国系统（Thy1-5）、甲状腺细胞病理学报告的贝塞斯达系统（BSRTC）以及意大利解剖病理学和细胞学会（SIAPEC）分类是甲状腺细胞病理学最重要的国际分类。无论使用哪种系统，细胞病理学家们对于“不确定”类别仍存在争议，特别是在诊断标准、亚分类的临床影响以及分子技术的作用方面。
我们旨在回答以下问题：在细胞学标本中是否存在共同标准，能够将不确定的滤泡性病变分为亚类？这种可能的亚分类的真正临床影响是什么？
在1150例连续的甲状腺细针穿刺（FNA）标本中，80例患者的结节最终细胞学报告为Tir3（SIAPEC）/Thy3。根据形态学标准对这80例病例进行重新评估并分为三组：纯滤泡性增生、许特莱细胞滤泡性病变和非典型增生。
16例（20%）病例被归类为纯滤泡性增生，40例（50%）为许特莱细胞滤泡性病变，24例（30%）为非典型增生。57例（71%）进行了手术。细胞组织学相关性显示，滤泡性腺瘤是手术治疗病例中最常见的最终诊断（2 /57，42%）。Tir3类别的总体恶性率为28%（16/57）。非典型增生比滤泡性病变组更常为恶性（53%对19%，P = 0.019）。
可以采用一种五级分类法，将“恶性不确定”类别细分为“滤泡性增生”和“非典型病变”。由于其恶性风险较高，对非典型病变进行手术治疗是合理的。未来，引入基因检测可能有助于对它们进行分层，确定非典型病变更准确的恶性风险，并验证良性的滤泡性增生。
