Department of Otolaryngology, South Infirmary University Hospital, Cork, Ireland.
Department of Pathology, Cork University Hospital, Cork, Ireland.
JAMA Otolaryngol Head Neck Surg. 2014 Dec;140(12):1117-23. doi: 10.1001/jamaoto.2014.2548.
The follicular variant (FV) of papillary thyroid carcinoma (PTC) is an important subtype that can be difficult to diagnose using preoperative cytologic analysis.
To compare conventional and FV PTC with regard to preoperative cytologic diagnosis using a tiered thyroid cytologic reporting system, tumor size at diagnosis, presence of invasion, and implications on prognostic scores.
DESIGN, SETTING, AND PARTICIPANTS: This retrospective study was conducted in an academic teaching hospital and included 99 patients with conventional (n = 65) or FV (n = 34) PTC.
Preoperative thyroid cytologic findings, originally reported using the tiered British Thy system, were recategorized according to the Bethesda classification system. Pathologic features recorded included tumor size, presence of extrathyroid extension (ETE), and metastases. Prognostic scores were calculated according to the MACIS system.
Differences in patient demographics, preoperative cytologic findings, tumor pathologic features, and prognostic risk categories between conventional and FV PTC were studied.
There were no differences in patient age or sex. Cytologic findings from FV PTC were significantly more likely to be reported in a lower-risk category than those from conventional PTC for (1) malignant vs lower-risk category (22 [56%] vs 2 [8%]); (2) suspected malignant or malignant vs lower-risk category (26 [66%] vs 6 [23%]); and (3) follicular neoplasm or higher-risk category vs lower-risk category (34 [87%] vs 10 [38%]) (P < .001 for all 3 comparisons). There was also a significantly higher likelihood of false-negative cytologic findings among FV PTC cases (5 [19%] vs 1 [3%]) (P = .03). The mean size of FV PTC lesions (25.9 mm) at the time of pathologic diagnosis was significantly greater than that of conventional PTC lesions (15.5 mm) (P = .02). Even after exclusion of "coincidental" carcinomas, FV PTC tumors were significantly larger than conventional PTC tumors (31.7 vs 22.4 mm; P = .03). In contrast, FV PTC was significantly less likely to show ETE (0 of 34 vs 10 of 65; P = .01). There were no significant differences between FV PTC and conventional PTC in proportion of patients in intermediate- and high-risk prognostic groups combined (21 [62%] vs 38 [58%]) (P = .83) or in mean MACIS scores (4.68 and 4.38, respectively; P = .18).
Preoperative cytologic findings from FV PTC were more likely than those from conventional PTC to indicate a lower risk category, and FV PTC tumors were larger at time of diagnosis. On the other hand, owing to a lower incidence of ETE in conventional PTC, there was no difference in prognostic score at diagnosis.
滤泡型甲状腺癌（PTC）是一种重要的亚型，使用术前细胞学分析诊断可能具有挑战性。
使用分层甲状腺细胞学报告系统，比较常规型和滤泡型 PTC 的术前细胞学诊断、诊断时的肿瘤大小、是否存在侵袭以及对预后评分的影响。
设计、设置和参与者：本回顾性研究在一家学术教学医院进行，纳入了 99 例常规型（n=65）或滤泡型（n=34）PTC 患者。
根据 Bethesda 分类系统，对术前甲状腺细胞学发现进行重新分类，这些发现最初是使用分层的英国甲状腺系统报告的。记录的病理特征包括肿瘤大小、是否存在甲状腺外扩展（ETE）和转移。根据 MACIS 系统计算预后评分。
研究了常规型和滤泡型 PTC 之间患者人口统计学、术前细胞学发现、肿瘤病理特征和预后风险类别的差异。
患者年龄和性别无差异。滤泡型 PTC 的细胞学发现更有可能被报告为较低风险类别，而非常规 PTC：（1）恶性 vs 较低风险类别（22[56%] vs 2[8%]）；（2）可疑恶性或恶性 vs 较低风险类别（26[66%] vs 6[23%]）；和（3）滤泡性肿瘤或较高风险类别 vs 较低风险类别（34[87%] vs 10[38%]）（所有 3 种比较的 P 值均<0.001）。滤泡型 PTC 病例中假阴性细胞学发现的可能性也显著更高（5[19%] vs 1[3%]）（P=0.03）。滤泡型 PTC 病变的平均大小（25.9 毫米）在病理诊断时明显大于常规 PTC 病变（15.5 毫米）（P=0.02）。即使排除“偶然”癌，滤泡型 PTC 肿瘤的大小仍明显大于常规 PTC 肿瘤（31.7 毫米 vs 22.4 毫米；P=0.03）。相比之下，滤泡型 PTC 发生 ETE 的可能性明显较小（34 例中 0 例 vs 65 例中 10 例；P=0.01）。滤泡型 PTC 和常规 PTC 患者在中危和高危预后组的比例方面没有显著差异（21[62%] vs 38[58%]）（P=0.83），或平均 MACIS 评分方面也没有差异（分别为 4.68 和 4.38；P=0.18）。
滤泡型 PTC 的术前细胞学发现比常规型 PTC 更有可能提示较低的风险类别，并且滤泡型 PTC 在诊断时的肿瘤更大。另一方面，由于常规型 PTC 的 ETE 发生率较低，因此诊断时的预后评分没有差异。
