Faculty of Medicine, Department of Pathology, Kocaeli University, Kocaeli, Turkey.
Diagn Cytopathol. 2020 Nov;48(11):986-997. doi: 10.1002/dc.24533. Epub 2020 Aug 3.
Fine needle aspiration cytopathology (FNAC) is the most reliable tool for evaluating thyroid nodules. However, diagnosing Bethesda category III, atypia/follicular lesion of undetermined significance (AUS/FLUS), is a major limitation. The aim of this study was to evaluate the risk of malignancy (RoM) in AUS/FLUS nodules. A systematic review was also carried out analyzing the largest series.
Totally 1750 cases (9%) diagnosed with AUS/FLUS were evaluated retrospectively out of 19 392 cases within last 13 years. All patients undergoing surgery for AUS/FLUS were included into the study. Histopathology results were correlated; the impact of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) diagnosis on RoM is evaluated.
Of the 280 patients (16%) undergoing surgery, neoplasia were detected in 177 (RoN:63.2%) and malignancy in 119 (RoM:42.5%) of these neoplasia. Follicular variant of papillary thyroid carcinoma (FVPTC) was the commonest malignancy (55.5%). Additional 58 (20.7%) nodules were neoplastic, of which 26 (9.3%) were encapsulated follicular tumors with unknown malignancy potential (FT-UMP) and 32 (11.4%) were follicular adenomas. The remaining 103 patients (36.8%) had non-neoplastic nodules. After reevaluation of the encapsulated FVPTC cases, 20 of them were NIFTP and RoM dropped to 35.4% with a relative decrease of 16.7% and an absolute decrease of 7.1%.
In our series, 42.5% of nodules with AUS/FLUS were malignant; 63.2% of them were neoplastic. The RoM and RoN for AUS/FLUS nodules are still much higher than the revised expected RoM of international guidelines even after NIFTP cases excluded. Therefore, current recommendations should be reevaluated periodically in view of detailed clinicopathologic studies.
细针穿刺细胞学检查（FNAC）是评估甲状腺结节的最可靠工具。然而，诊断 Bethesda 分类 3 级、不典型/滤泡性病变意义不明确（AUS/FLUS）是一个主要的局限性。本研究旨在评估 AUS/FLUS 结节的恶性肿瘤风险（RoM）。还进行了系统评价，分析了最大系列。
在过去 13 年中，对 19392 例患者进行了回顾性评估，其中 9%（1750 例）诊断为 AUS/FLUS。所有因 AUS/FLUS 而行手术的患者均纳入本研究。将组织病理学结果进行相关性分析；评估非浸润性滤泡性甲状腺肿瘤伴乳头状核特征（NIFTP）诊断对 RoM 的影响。
在 280 例（16%）接受手术的患者中，177 例（RoN：63.2%）发现肿瘤，其中 119 例（RoM：42.5%）为恶性肿瘤。甲状腺滤泡状癌（FVPTC）是最常见的恶性肿瘤（55.5%）。另有 58 例（20.7%）结节为肿瘤性，其中 26 例（9.3%）为包膜滤泡性肿瘤伴未知恶性潜能（FT-UMP），32 例（11.4%）为滤泡性腺瘤。其余 103 例（36.8%）为非肿瘤性结节。在重新评估包膜 FVPTC 病例后，其中 20 例为 NIFTP，RoM 下降至 35.4%，相对下降 16.7%，绝对下降 7.1%。
在本系列中，42.5%的 AUS/FLUS 结节为恶性；其中 63.2%为肿瘤性。即使排除 NIFTP 病例后，AUS/FLUS 结节的 RoM 和 RoN 仍远高于国际指南修订后的预期 RoM。因此，应根据详细的临床病理研究定期重新评估当前的建议。
