PURPOSE The classification of indeterminate cytopathology at thyroid fine-needle-aspiration (FNA) has been updated to reduce the number of unnecessary surgery; the 2014 Italian classification introduced the low-risk (TIR3A) and high-risk (TIR3B) subcategories. Aim of this study was to identify the ultrasonographic (US), clinical and cytological predictors of malignancy among TIR3B nodules from a single institution. METHODS A prospective observational study including 1844 patients who underwent thyroid FNA from June 2014 to January 2019. Ultrasonographic, clinical and cytological features were recorded. All TIR3B diagnoses were referred to surgery. According to final histology, patients were divided into thyroid cancer (TC) or benign nodules. Chi-square test, or Fisher exact test when appropriate, were used to compare groups and logistic regression analyses were used to determine independent predictors of malignancy. RESULTS Of 1844 FNAs, 96 (5.2%) were TIR3B. Histology report was available in 65. Among them, 25 (38.5%) were TC. Predictors of TC were nodule size < 20 mm [Odds Ratio (OR) = 5.88, 95% CI 1.91-18.11, p = 0.002], absence or weak intralesional flow [OR = 0.3, 95% CI 0.09-0.77, p = 0.015], microcalcifications [OR = 6.5, 95% CI 1.90-21.93, p = 0.003] at US; nuclear inclusions [OR = 25.3, 95% CI 1.34-476.07, p = 0.031] and chromatin clearing [OR = 3.7, 95% CI 1.27-10.99, p = 0.017] at cytopathology. Patients aged < 55 years had a significantly higher risk of TC [OR = 9.7, 95% CI 2.79-34.07, p < 0.001]. In multivariate analysis, age < 55 and nodule size < 20 mm resulted as independent risk factors. CONCLUSIONS Patients < 55 years receiving a diagnosis TIR3B on nodules < 20 mm, with microcalcifications, showing specific nuclear atypia at cytopathology are more likely to have TC. Combining US, cytological and clinical features could help determining which patients with a TIR3B diagnosis should be referred to surgery.

中文翻译：

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高危不确定（TIR3B）细胞病理学甲状腺结节的恶性程度预测指标。

目的对甲状腺细针穿刺术（FNA）的不确定细胞病理学分类进行了更新，以减少不必要的手术次数；2014年意大利分类引入了低风险（TIR3A）和高风险（TIR3B）子类别。这项研究的目的是确定单一机构中TIR3B结节中恶性的超声检查（US），临床和细胞学预测指标。方法一项前瞻性观察性研究，包括2014年6月至2019年1月接受甲状腺FNA治疗的1844例患者，并记录了超声，临床和细胞学特征。所有TIR3B诊断均转诊为手术。根据最终的组织学，将患者分为甲状腺癌（TC）或良性结节。卡方检验或费舍尔精确检验（如适用），被用来比较各组，逻辑回归分析被用来确定恶性肿瘤的独立预测因子。结果在1844个FNA中，有96个（5.2％）是TIR3B。有65个组织学报告。其中25个（38.5％）是TC。TC的预测指标是结节大小<20 mm [几率（OR）= 5.88，95％CI 1.91-18.11，p = 0.002]，病灶内血流缺乏或微弱[OR = 0.3，95％CI 0.09-0.77，p = 0.015 ]，在美国的微钙化[OR = 6.5，95％CI 1.90-21.93，p = 0.003]；细胞病理学检查显示核内含物[OR = 25.3，95％CI 1.34-476.07，p = 0.031]和染色质清除[OR = 3.7，95％CI 1.27-10.99，p = 0.017]。<55岁的患者发生TC的风险显着更高[OR = 9.7，95％CI 2.79-34.07，p <0.001]。在多变量分析中，年龄<55岁和结节大小<20 mm是独立的危险因素。结论<55岁的患者接受诊断为TIR3B的结节<20 mm，并有微钙化，表明在细胞病理学上存在特定的核型异型，更可能患有TC。结合US，细胞学和临床特征可以帮助确定哪些具有TIR3B诊断的患者应转诊手术。