BRAFK601E 是一种罕见突变，通常见于包膜滤泡型甲状腺肿瘤。先前对 BRAFK601E 阳性甲状腺肿瘤的研究是在实施具有乳头状核特征的非侵袭性滤泡性肿瘤（NIFTP）诊断之前进行的。本研究旨在描述 BRAFK601E 阳性肿瘤的特征，并评估引入 NIFTP 后这些患者的诊断和治疗方面的变化。我们评估了 25 个 BRAFK601E 呈阳性的甲状腺肿瘤，并根据 NIFTP 标准进行诊断。将这些肿瘤的临床病理特征和复发率与接受 NIFTP 诊断之前诊断的 29 个 BRAFK601E 阳性肿瘤进行比较。对 10 个 BRAFK601E 阳性肿瘤进行 RNA 测序分析。在当前的研究中，72% 的 BRAFK601E 阳性肿瘤在切除时被诊断为非侵袭性肿瘤，其中 NIFTP（占所有肿瘤的 48%）是最常见的诊断。 BRAFK601E阳性肿瘤表现出RAS样基因表达谱，其BRAF-RAS评分（BRS）和甲状腺分化评分（TDS）与BRAFV600E阳性肿瘤不同（P<0.001）。自2016年以来，BRAFK601E阳性肿瘤患者较少接受甲状腺全切除术（41% vs 100%，P<0.001）和接受放射性碘治疗（7% vs 75%，P<0.001）。当前或 2016 年的研究中，孤立的 BRAFK601E 突变呈阳性的肿瘤均未在随访中显示复发。我们的研究表明，大多数 BRAFK601E 阳性肿瘤是低风险的 RAS 样肿瘤，所有研究病例中有一半被诊断为 NIFTP。自2016年以来，BRAFK601E阳性结节患者接受的积极治疗较少。没有其他高风险特征的 BRAFK601E 阳性肿瘤复发的风险似乎较低，并且不使用放射性碘的肺叶切除术可能足以治疗这些患者。

BRAFK601E is an uncommon mutation typically found in encapsulated follicular-patterned thyroid tumors. Previous studies on BRAFK601E-positive thyroid tumors were conducted before implementation of the non-invasive follicular neoplasm with papillary-like nuclear features (NIFTP) diagnosis. This study aimed to characterize BRAFK601E-positive tumors and evaluate changes in diagnosis and management of these patients after introduction of NIFTP. We evaluated 25 thyroid tumors that were positive for BRAFK601E and diagnosed considering the NIFTP criteria. Clinicopathologic characteristics and recurrence rates of these tumors were compared to 29 BRAFK601E-positive tumors diagnosed prior to the acceptance of NIFTP diagnosis. RNA-seq analysis was performed on 10 BRAFK601E-positive tumors. In the current study, 72% of BRAFK601E-positive tumors were diagnosed as non-invasive tumors on resection, with NIFTP (48% of all tumors) being the most common diagnosis. BRAFK601E-positive tumors exhibited a RAS-like gene expression profile with BRAF-RAS score (BRS) and thyroid differentiation score (TDS) distinct from BRAFV600E-positive tumors (P<0.001). Since 2016, patients with BRAFK601E-positive tumors less frequently underwent total thyroidectomy (41% vs 100%, P<0.001) and received radioiodine (7% vs 75%, P<0.001). None of the tumors positive for an isolated BRAFK601E mutation from the current or 2016 studies showed recurrences on follow-up. Our study demonstrates that most BRAFK601E-positive tumors are low risk, RAS-like tumors, which were diagnosed as NIFTP in half of all study cases. Since 2016, patients with BRAFK601E-positive nodules receive less aggressive treatment. The risk of recurrence of BRAFK601E-positive tumors without other, high-risk features appears to be low, and lobectomy without radioiodine is likely sufficient treatment for these patients.