Department of Clinical and Experimental Medicine, Unit of Endocrinology, Pisa University Hospital, Pisa 56124, Italy.
Department of Surgical, Medical, Molecular Pathology and Critical Area, Unit of Endocrine Surgery, Pisa University Hospital, Pisa 56126, Italy.
Eur J Endocrinol. 2023 Aug 2;189(2):175-182. doi: 10.1093/ejendo/lvad095.
Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFT-P) is an encapsulated follicular variant of papillary thyroid carcinoma (PTC) with nonaggressive clinical behavior. However, since its diagnosis is exclusively possible after surgery, it represents a clinical challenge. Neck ultrasound (US) shows good sensitivity and specificity in suggesting malignancy in thyroid nodules. However, little information is available about its ability in identifying NIFT-P.
The aim of this study was to evaluate the US features of NIFT-P, comparing them with other follicular-patterned thyroid tumors, and to test the ability of the main US risk stratification system (RSS) in identifying NIFT-P.
We retrospectively evaluated 403 consecutive patients submitted to thyroid surgery, with positive histology for at least 1 nodule being NIFT-P, follicular variant of PTC (FV-PTC), follicular thyroid carcinoma (FTC), or follicular adenoma (FA).
The US features of NIFT-P (n = 116), FV-PTC (n = 170), FTC (n = 76), and FA (n = 90) were reported. Follicular variant of PTC and FTC more frequently showed irregular margins, presence of calcifications, "taller than wide" shape, and the absence of halo compared with NIFT-P. Furthermore, FTC and also FA were larger and more frequently hypoechoic than NIFT-P. Most cases (77%) showed an indeterminate cytology. Regardless of the US RSS considered, NIFT-P and FA were less frequently classified in the high-suspicious category compared with FV-PTC and FTC.
Ultrasound features of NIFT-P are frequently superimposable to those of nodules with low suspicion of malignancy. The NIFT-P is almost never classified in the high-suspicious category according to the main US RSS. Therefore, although the preoperative identification of NIFT-P remains a challenge, neck US can be integrated in the algorithm of management of nodules with indeterminate cytology, suggesting a possible conservative approach in those with low-suspicious features.
非侵袭性滤泡性甲状腺肿瘤伴乳头状核特征（NIFT-P）是一种包膜性滤泡状甲状腺癌（PTC）的滤泡变体，具有侵袭性临床行为。然而，由于其诊断仅在手术后才能确定，因此这是一个临床挑战。颈部超声（US）在提示甲状腺结节恶性方面具有良好的敏感性和特异性。然而，关于其识别 NIFT-P 的能力的信息很少。
本研究旨在评估 NIFT-P 的 US 特征，将其与其他滤泡性甲状腺肿瘤进行比较，并测试主要 US 风险分层系统（RSS）识别 NIFT-P 的能力。
我们回顾性评估了 403 例连续接受甲状腺手术的患者，其中至少 1 个结节的组织学阳性为 NIFT-P、滤泡状 PTC（FV-PTC）、滤泡状甲状腺癌（FTC）或滤泡性腺瘤（FA）。
报告了 NIFT-P（n=116）、FV-PTC（n=170）、FTC（n=76）和 FA（n=90）的 US 特征。与 NIFT-P 相比，FV-PTC 和 FTC 更常表现为不规则边缘、存在钙化、“高宽比”形状和缺乏晕环。此外，FTC 甚至 FA 比 NIFT-P 更大且更常呈低回声。大多数病例（77%）表现为不确定的细胞学。无论考虑哪种 US RSS，与 FV-PTC 和 FTC 相比，NIFT-P 和 FA 较少被归类为高可疑类别。
NIFT-P 的超声特征常与低恶性可疑度结节的特征相似。根据主要 US RSS，NIFT-P 几乎从未被归类为高可疑类别。因此，尽管术前识别 NIFT-P 仍然具有挑战性，但颈部 US 可以整合到具有不确定细胞学的结节管理算法中，提示对于具有低可疑特征的结节可能采取保守方法。
