A case report of NIFTP-like tumor with lymph node metastasis and reflections on diagnosis and treatment: When classic theory meets clinical exception
伴淋巴结转移的NIFTP样肿瘤1例报道及诊疗反思：当经典理论遭遇临床例外

摘要

目的 探讨伴淋巴结转移的具有乳头样核特征的非浸润性甲状腺滤泡性肿瘤（NIFTP）诊断矛盾及处理策略。方法 报道1例初始诊断为NIFTP但术后发现淋巴结转移的病例，结合2019-2024年文献分析诊疗争议。结果 患者女，42岁，甲状腺右叶2.6cm结节（TI-RADS III类，甲状腺左叶2.2cm结节（TI-RADS III类）。行右叶全切加左侧次全切除后石蜡病理，右叶甲状腺乳头状癌，左侧符合NIFTP（WHO 2022标准），基因检测全阴性。补充左侧叶全切+中央区清扫发现，左侧中央区1/5枚淋巴结转移。术后行促甲状腺激素（TSH）抑制治疗，目前术后随访中。结论 严格诊断的NIFTP出现淋巴结转移需警惕：或为浸润性癌误诊，或是未知亚型，建议多中心病理复核及扩大分子检测。

Abstract

Objective To explore the diagnostic dilemmas and management strategies for Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features (NIFTP) with lymph node metastasis.
Methods A case initially diagnosed as NIFTP but found to have lymph node metastasis postoperatively was reported, combined with literature analysis from 2019 to 2024 to address diagnostic controversies.
Results A 42-year-old female patient had a 2.6 cm nodule in the right thyroid lobe (TI-RADS category III) and a 2.2 cm nodule in the left thyroid lobe (TI-RADS category III). After right lobectomy and left subtotal thyroidectomy, paraffin pathology revealed papillary thyroid carcinoma in the right lobe, while the left lobe was consistent with NIFTP (WHO 2022 criteria), with all molecular tests negative. A subsequent left lobectomy and central compartment dissection identified lymph node metastasis in 1/5 nodes in the left central compartment. Postoperative Thyroid-Stimulating Hormone (TSH) suppression therapy was administered, and the patient remains under follow-up.
Conclusion   Strictly diagnosed NIFTP with lymph node metastasis warrants vigilance: it may represent misdiagnosis of invasive cancer or an unknown subtype, necessitating multicenter pathological review and expanded molecular testing.