Roden Anja C, Yi Eunhee S, Jenkins Sarah M, Donovan Janis L, Cassivi Stephen D, Garces Yolanda I, Marks Randolph S, Aubry Marie-Christine
Department of Laboratory Medicine & Pathology, Mayo Clinic Rochester, MN, 55905, USA.
Department of Laboratory Medicine & Pathology, Mayo Clinic Rochester, MN, 55905, USA.
Hum Pathol. 2015 Jan;46(1):17-25. doi: 10.1016/j.humpath.2014.10.001. Epub 2014 Oct 14.
The prognostic importance of histologic classifications of thymic epithelial neoplasms is controversial. Evidence suggests that difficulties in reproducibility affect prognostic studies. Two thoracic pathologists independently classified 80 cases of type A or B3 thymoma and thymic carcinoma according to World Health Organization (WHO) classification. Ki-67 labeling index (LI) was used to identify cutoff points between WHO types. Recursive partitioning (Rpart) and ad hoc methods separated the data points. The pathologists agreed on type A (n = 31), type B3 (n = 21), and thymic carcinoma (n = 14). Ki-67 LI differed between types A and B3 (P < .001) and between thymic carcinoma and type A (P < .001) or type B3 (P = .001). Mitotic activity differed between thymic carcinoma and type A (P < .001) or type B3 (P < .001). Rpart revealed Ki-67 LI greater than 14.0% only in thymic carcinoma; cases with Ki-67 LI less than 5.1% did not represent thymic carcinoma. Ad hoc analysis showed Ki-67 LI greater than or equal to 13.5% represents thymic carcinoma; only type A had Ki-67 LI less than 2%. The pathologists disagreed on histologic type in 14 cases. In 11 of 14 cases with available Ki-67, the Rpart method predicted the WHO type; in 7 of 14 cases, the ad hoc method predicted the WHO type. In conclusion, Ki-67 LI is helpful in differentiating thymic epithelial neoplasms, with Ki-67 LI less than 2% and greater than or equal to 13.5% distinguishing type A thymoma and thymic carcinoma, respectively.
胸腺上皮肿瘤组织学分类的预后重要性存在争议。有证据表明，可重复性方面的困难影响了预后研究。两名胸科病理学家根据世界卫生组织（WHO）分类标准，对80例A型或B3型胸腺瘤及胸腺癌进行了独立分类。采用Ki-67标记指数（LI）来确定WHO各类型之间的分界点。递归分割法（Rpart）和特定方法对数据点进行了分离。两位病理学家对A型（n = 31）、B3型（n = 21）和胸腺癌（n = 14）的分类达成了一致。A型和B3型之间的Ki-67 LI存在差异（P <.001），胸腺癌与A型（P <.001）或B3型（P =.001）之间的Ki-67 LI也存在差异。胸腺癌与A型（P <.001）或B3型（P <.001）之间的有丝分裂活性存在差异。Rpart分析显示，仅在胸腺癌中Ki-67 LI大于14.0%；Ki-67 LI小于5.1%的病例不代表胸腺癌。特定分析显示，Ki-67 LI大于或等于13.5%代表胸腺癌；只有A型的Ki-67 LI小于2%。在14例病例中，两位病理学家对组织学类型存在分歧。在14例有可用Ki-67数据的病例中，11例Rpart方法预测了WHO类型；14例中有7例特定方法预测了WHO类型。总之，Ki-67 LI有助于鉴别胸腺上皮肿瘤，Ki-67 LI小于2%和大于或等于13.5%分别可区分A型胸腺瘤和胸腺癌。
