Suster S, Moran C A
Department of Pathology, The Ohio State University, Columbus 43210, USA.
Semin Diagn Pathol. 1999 Feb;16(1):2-17.
Primary thymic epithelial neoplasms have been the source of much controversy over the years because of difficulties in their histopathologic classification and prognostication of clinical behavior. Despite recent advances in our understanding of the immunopathology and molecular pathology of these neoplasms, no universally accepted system of classification is yet available for these tumors. A variety of classification schemes have been proposed in the past based on either morphological, histogenetic, or immunophenotypic considerations. For the most part, the majority of such classifications have been merely descriptive with little value for prognostication, or have proven cumbersome and difficult to apply in clinical practice. Recent studies have shown that primary thymic epithelial neoplasms, rather than representing several discrete, separate entities constitute part of a continuous spectrum of differentiation ranging from well-differentiated neoplasms to poorly-differentiated neoplasms. Based on these observations, a novel classification of primary thymic epithelial neoplasms has been proposed that divides these tumors into three easily reproducible diagnostic categories based on their degrees of differentiation: thymoma, atypical thymoma, and thymic carcinoma (corresponding to well-differentiated, moderately-differentiated, and poorly-differentiated neoplasms, respectively). The histopathologic features and diagnostic criteria for these tumors is the subject of this review.
多年来，原发性胸腺上皮肿瘤一直备受争议，因为其组织病理学分类及临床行为的预后判断存在困难。尽管近年来我们对这些肿瘤的免疫病理学和分子病理学有了进一步了解，但目前尚无普遍接受的分类系统。过去曾基于形态学、组织发生学或免疫表型等因素提出过多种分类方案。大多数情况下，这些分类大多只是描述性的，对预后判断价值不大，或者已证明在临床实践中繁琐且难以应用。最近的研究表明，原发性胸腺上皮肿瘤并非代表几个离散、独立的实体，而是构成了一个从高分化肿瘤到低分化肿瘤的连续分化谱系的一部分。基于这些观察结果，提出了一种原发性胸腺上皮肿瘤的新分类方法，根据其分化程度将这些肿瘤分为三个易于重现的诊断类别：胸腺瘤、非典型胸腺瘤和胸腺癌（分别对应高分化、中分化和低分化肿瘤）。这些肿瘤的组织病理学特征和诊断标准是本综述的主题。
