Cipriani Nicole A, Nagar Sapna, Kaplan Sharone P, White Michael G, Antic Tatjana, Sadow Peter M, Aschebrook-Kilfoy Briseis, Angelos Peter, Kaplan Edwin L, Grogan Raymon H
1 Department of Pathology, The University of Chicago , Chicago, Illinois.
2 Department of Surgery, Oakland University William Beaumont School of Medicine , Royal Oak, Michigan.
Thyroid. 2015 Nov;25(11):1209-16. doi: 10.1089/thy.2015.0297. Epub 2015 Oct 26.
Follicular thyroid carcinoma (FTC) comprises 10% of differentiated thyroid cancers. Diagnostic controversy and interobserver variability render the practical diagnosis of FTC difficult. Overall survival rates vary (46-97%). The aims of this study were to review FTC histologically at the authors' tertiary care institution and to evaluate long-term survival and recurrence.
Diagnostic slides from 66 FTC cases (1965-2007) were reviewed by three pathologists from two institutions (blinded to clinical outcomes), and consensus was obtained. Patient demographics, tumor characteristics, and treatment, survival, and recurrence data were collected. Thyroid cancer-specific and recurrence-free survival were calculated by original and reclassified diagnoses.
Forty-seven cases (71%) were reclassified: 24 (36%) to papillary thyroid carcinoma (PTC), 18 (27%) to follicular adenoma (FA), and five (8%) to poorly differentiated carcinoma (PDC). Nineteen (29%) maintained a diagnosis of FTC. The extent of surgical resection and rates of radioiodine treatment did not differ by reclassification diagnosis. Pre-review FTC-specific survival was 83.5% and 75.1% at 10 and 20 years, respectively. Following contemporary reclassification, FTC-specific survival was 77% and 33.7% at 10 and 20 years, respectively. There were no cancer-specific deaths in the FA or PTC groups.
Over the past 50 years, changes in our understanding of the pathogenesis, histology, and behavior of thyroid carcinoma may partially account for the changes in histologic diagnosis. Elimination of PTC and FA "contaminants" led to decrease in survival following reclassification. Variability in histologic interpretation contributes to diagnostic challenges in follicular lesions. Histologic review of thyroid tumors for research studies is crucial, especially given the ever-changing diagnostic criteria.
滤泡状甲状腺癌（FTC）占分化型甲状腺癌的10%。诊断争议和观察者间差异使得FTC的实际诊断颇具难度。总体生存率有所不同（46%-97%）。本研究的目的是在作者所在的三级医疗机构对FTC进行组织学回顾，并评估长期生存和复发情况。
来自两个机构的三名病理学家（对临床结果不知情）对66例FTC病例（1965 - 2007年）的诊断切片进行了回顾，并达成了共识。收集了患者的人口统计学资料、肿瘤特征以及治疗、生存和复发数据。根据原始诊断和重新分类诊断计算甲状腺癌特异性生存率和无复发生存率。
47例（71%）病例被重新分类：24例（36%）重新分类为乳头状甲状腺癌（PTC），18例（27%）重新分类为滤泡性腺瘤（FA），5例（8%）重新分类为低分化癌（PDC）。19例（29%）维持FTC诊断。手术切除范围和放射性碘治疗率在重新分类诊断中并无差异。回顾前FTC特异性生存率在10年和20年时分别为83.5%和75.1%。经过当代重新分类后，FTC特异性生存率在10年和20年时分别为77%和33.7%。FA或PTC组无癌症特异性死亡病例。
在过去50年中，我们对甲状腺癌发病机制、组织学和行为的理解变化可能部分解释了组织学诊断的变化。去除PTC和FA“污染物”导致重新分类后的生存率下降。组织学解释的差异导致滤泡性病变的诊断面临挑战。对甲状腺肿瘤进行组织学回顾对于研究至关重要，尤其是考虑到诊断标准不断变化的情况。
