From the Department of Pathology & Laboratory Medicine, the Hospital of the University of Pennsylvania, Philadelphia.
Arch Pathol Lab Med. 2021 Jun 1;145(6):659-663. doi: 10.5858/arpa.2019-0689-RA.
CONTEXT.—: This article presents a review of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), including its separation from follicular variant of papillary carcinoma of the thyroid, its evolution, and current definition and pathologic characteristics.
OBJECTIVES.—: To emphasize the understanding of the concept of NIFTP as a neoplasm based on molecular analyses, its critical histopathologic features, the microscopic findings that exclude the diagnosis, and the importance of complete sectioning of the tumor to exclude neoplasms that should be diagnosed as carcinomas. Important distinctions are discussed including difficulties with literature that shows NIFTP with metastases, inadequacy of sectioning of the tumor, and lack of descriptive histology of the surrounding thyroid and possible other lesions.
DATA SOURCES.—: Review of articles in the English literature on NIFTP, as well as comparative papers showing differences and distinctions between this entity and papillary carcinomas.
CONCLUSIONS.—: This article concludes that with the current state of knowledge on NIFTP with studies from all over the world, this entity is a low-risk neoplasm that, when diagnosed using appropriate criteria, should not be associated with metastatic or recurrent disease, at least on intermediate length of follow-up. This review includes discussion of multifocal NIFTP, as well as the recently defined micro-NIFTP (1 cm or less), and describes features of the tumor that remain to be studied and correlated with outcome: oncocytic variants of NIFTP, percentage of allowable solid areas of growth in the lesions, and definitions of true neoplastic papillae and hyperplastic ones and how these should influence the diagnosis of NIFTP.
本文回顾了不典型滤泡性甲状腺肿瘤伴乳头状核特征（NIFTP），包括其与甲状腺滤泡状乳头状癌的区别、演变、目前的定义和病理特征。
强调理解 NIFTP 作为一种基于分子分析的肿瘤概念，其关键的组织病理学特征，排除诊断的微观发现，以及完整切除肿瘤的重要性，以排除应诊断为癌的肿瘤。讨论了重要的区别，包括有转移的 NIFTP 文献显示的困难、肿瘤切片不足，以及对周围甲状腺和可能的其他病变的描述性组织学缺乏。
对英文文献中关于 NIFTP 的文章以及比较性论文进行了回顾，这些论文显示了该实体与乳头状癌之间的差异和区别。
本文认为，根据目前全世界对 NIFTP 的研究，该实体是一种低风险的肿瘤，当使用适当的标准进行诊断时，至少在中期随访中，不应与转移性或复发性疾病相关。本文综述包括对多灶性 NIFTP 的讨论，以及最近定义的微小 NIFTP（1 厘米或更小），并描述了仍有待研究并与结果相关的肿瘤特征：NIFTP 的嗜酸细胞变体、病变中允许的实性区域的百分比，以及真正的肿瘤性乳头和增生性乳头的定义，以及这些应如何影响 NIFTP 的诊断。
