具有乳头样核特征的非浸润性甲状腺滤泡性肿瘤4例临床病理分析

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features: a clinicopathological analysis of four cases

目的探讨具有乳头样核特征的非浸润性甲状腺滤泡性肿瘤(NIFTP)的病理学特征。方法回顾性分析4例NIFTP的临床特征、形态学特点、免疫表型、基因改变,并复习相关文献。结果 4例患者男、女各2例,年龄41～58岁。3例无明显症状,1例表现为气道轻度受阻。B超示甲状腺结节,TI-RADS 3-4B类。甲状腺细针穿刺涂片示可疑甲状腺乳头状癌。大体肿瘤最大径为0.1～7.4cm,边界清楚或有完整包膜。镜下部分滤泡上皮细胞呈甲状腺乳头状癌的核特征,可见"喷洒征",未见脉管及包膜侵犯。免疫组化:肿瘤细胞不同程度CK19、cyclinD1、HBME-1、galectin-3(+)。K-RAS、N-RAS及B-RAF基因检测未发现突变。患者行双侧甲状腺切除术后随访1～7个月,未见复发及转移。结论 NIFTP是一种交界性甲状腺肿瘤,具有极低度恶性潜能。该肿瘤多为无意中发现的结节,组织发生及相关预后仍处于争论中。形态学、免疫组化及基因检测一定程度上有助于鉴别诊断。

Objective To investigate the pathological features of noninvasive follicular thyroid neoplasm with papillary-like nuclear features（NIFTP）. Methods The clinical, morphological, immunohistochemical features of four cases of NIFTP were analyzed retrospectively, and related literatures were reviewed. Results The patients were 2 males and 2 females, aged 41-58 years. There were no obvious symptoms in 3 cases, and 1 cases showed slight obstruction of the airway. Thyroid nodules were found incidentally by B-type ultrasound examination, and classified as TI-RADS 3-4 B. Fine needle aspiration revealed suspicious papillary thyroid carcinoma in some cases. The diameters of the tumors were 0.1-7.4 cm. Histologically, there were encapsulated or well-circumscribed follicular lesions. Some of the tumor cells showed nuclear characteristics of papillary thyroid carcinoma, ＂sprinkling＂ sign. Vascular and capsule invasion was not observed. Tumor cells were variably positive for CK19, cyclinD1, HBME-1 and galectin-3. No mutation was found in K-RAS, N-RAS and B-RAF genes. All the patients underwent bilateral thyroidectomy. Recurrence or metastasis was not found after 1-7 months follow-up. Conclusion NIFTP is a borderline thyroid tumor with a very low degree of malignant potential. Most patients present with the unintentional nodules. The histogenesis and prognosis of this tumor are still in dispute. Morphologic, immunohistochemical features and genetic test are helpful for differential diagnosis.