Department of Clinical and Experimental Medicine, University of Messina, Viale Gazzi, 98125, Messina, Italy.
Department of Human Pathology of Adult and Evolutive Age "Gaetano Barresi"-Section of Pathological Anatomy, University of Messina, Viale Gazzi, 98125, Messina, Italy.
Rev Endocr Metab Disord. 2018 Dec;19(4):301-309. doi: 10.1007/s11154-018-9474-z.
Although the incidence of some malignancy has decreased over the recent years, this is not the case of papillary thyroid microcarcinoma (PTMC), whose incidence has increased worldwide. Most PTMC are found incidentally after histological examination of specimens from surgery for benign thyroid disease. Hashimoto's thyroiditis, whose incidence has also increased, coexists in about one in three PTMC patients. Three different mechanisms have been proposed to clarify the association between chronic lymphocytic thyroiditis and PTMC, namely tumor development/growth by: (i) TSH stimulation, (ii) expression of certain proto-oncogenes, (iii) chemokines and other molecules produced by the lymphocytic infiltrate. Whether Hashimoto's thyroiditis protects against lymph node metastasis is debated. Overall, autommune thyroiditis seems to contribute to the favorable prognosis of PTMC. Major limitations of the studies so far performed include: (i) retrospective design, (ii) limited statistical power, (iii) high risk of selection bias, (iv) and predominant Asian ethnicity of patients. Full genetic profiling of both diseases and identification of environmental factors capable to trigger them, as well as well-powered prospective studies on different ethnical groups, may help understand their causal association and why their frequencies are continuing raising.
尽管近年来某些恶性肿瘤的发病率有所下降，但甲状腺微小乳头状癌（PTMC）的发病率却呈上升趋势，这种情况并非如此。大多数 PTMC 是在因良性甲状腺疾病手术切除标本的组织学检查中偶然发现的。桥本甲状腺炎的发病率也有所上升，约有三分之一的 PTMC 患者同时患有桥本甲状腺炎。目前提出了三种不同的机制来阐明慢性淋巴细胞性甲状腺炎与 PTMC 之间的关联，即：（i）TSH 刺激、（ii）某些原癌基因的表达、（iii）淋巴细胞浸润产生的趋化因子和其他分子。桥本甲状腺炎是否能预防淋巴结转移仍存在争议。总的来说，自身免疫性甲状腺炎似乎有助于改善 PTMC 的预后。迄今为止进行的研究主要存在以下局限性：（i）回顾性设计、（ii）统计能力有限、（iii）选择偏倚风险高、（iv）患者主要为亚洲人。对这两种疾病进行全面的基因分析，并确定能够引发它们的环境因素，以及在不同种族群体中进行大规模的前瞻性研究，可能有助于了解它们的因果关联，以及为什么它们的发病率仍在持续上升。
