The 2021 WHO Classification of Tumors of the Thymus and Mediastinum: What Is New in Thymic Epithelial,Germ Cell,and Mesenchymal Tumors?

This overview of the fifth edition of the WHO classification of thymic epithelial tumors (including thymomas, thymic carcinomas, and thymic neuroendocrine tumors [NETs]), mediastinal germ cell tumors, and mesenchymal neoplasms aims to (1) list established and new tumor entities and subtypes and (2) focus on diagnostic, molecular, and conceptual advances since publication of the fourth edition in 2015. Diagnostic advances are best exemplified by the immunohistochemical characterization of adenocarcinomas and the recognition of genetic translocations in metaplastic thymomas, rare B2 and B3 thymomas, and hyalinizing clear cell carcinomas. Advancements at the molecular and tumor biological levels of utmost oncological relevance are the findings that thymomas and most thymic carcinomas lack currently targetable mutations, have an extraordinarily low tumor mutational burden, but typically have a programmed death-ligand 1^high phenotype. Finally, data underpinning a conceptual advance are illustrated for the future classification of thymic NETs that may fit into the classification scheme of extrathoracic NETs. Endowed with updated clinical information and state-of-the-art positron emission tomography and computed tomography images, the fifth edition of the WHO classification of thymic epithelial tumors, germ cell tumors, and mesenchymal neoplasms with its wealth of new diagnostic and molecular insights will be a valuable source for pathologists, radiologists, surgeons, and oncologists alike. Therapeutic perspectives and research challenges will be addressed as well.     

Assessment of the ITMIG Statement on the WHO Histological Classification and of the Eighth TNM Staging of Thymic Epithelial Tumors of a Series of 188 Thymic Epithelial Tumors

IntroductionThymic epithelial tumors (TETs) are rare intrathoracic malignancies that are categorized histologically according to the WHO classification, which was recently updated in 2015 on the basis of a consensus statement of the International Thymic Malignancy Interest Group (ITMIG); at the same time, the standard Masaoka-Koga staging system is scheduled to be replaced by the eighth edition of the TNM staging classification by the American Joint Committee on Cancer/Union for International Cancer Control consortium. Our objectives were to analyze the feasibility of assessing ITMIG consensus major and minor morphological and immunohistochemical criteria and the eighth edition of the TNM staging classification in a routine practice setting.MethodsThis is a single-center study conducted at the Louis-Pradel Hospital of Lyon University, one of the largest centers for TETs in France. Overall, a large surgical series of 188 TETs diagnosed in 181 patients between 2000 and 2014 at our center were analyzed.ResultsThere were 89 men (49%) and 92 women (51%); 57 patients (31%) presented with myasthenia gravis at time of diagnosis. According to the WHO classification, there were nine type A thymomas (5%), 67 type AB thymomas (36%), 19 type B1 thymomas (10%), 46 type B2 thymomas (24%), 27 type B3 thymomas (14%), and 20 thymic carcinomas (11%). ITMIG consensus major criteria were identified in 100% of type A, AB, B1, and B2 thymomas. After restaging according to the eighth edition of the TNM staging classification, there were 127 stage I (84%), three stage II (2%), 17 stage IIIa (11%), no stage IIIb, two stage IVa (1%), and three stage IVb (2%) thymomas. Significant correlation between histological type and stage at diagnosis was maintained after restaging according the TNM classification.ConclusionComprehensive analysis of our well-characterized surgical series of 188 TETs indicates the feasibility and the diagnostic value of the ITMIG consensus statement on WHO histological classification and highlights the major switch in staging when the eighth edition of the TNM staging classification is applied.     

Trends in Incidence and Survival of Patients With Thymic Epithelial Tumor in a High-Incidence Asian Country: Analysis of the Korean Central Cancer Registry 1999 to 2017

IntroductionTo report the trends in incidence and survival associated with thymic epithelial tumors (TETs) in Korea.MethodsData from 1999 to 2017 were obtained from the Korean Central Cancer Registry. Age-standardized incidence rates and average annual percentage changes (AAPCs) were calculated. Net survival (NS) was estimated by the Pohar-Perme method.ResultsAmong 5812 patients diagnosed with having TETs, 58.9%, 38.1%, and 3.0% were diagnosed with having thymoma, thymic carcinoma, and thymic neuroendocrine tumor (NET), respectively. Age-standardized incidence rates were 0.50, 0.30, 0.18, and 0.02 per 100,000 for all TETs and the respective subtypes. There was an increase in incidence of all TETs (AAPC = 6.1%) and subtypes: thymoma (AAPC = 5.6%), thymic carcinoma (AAPC = 7.0%), and thymic NET (AAPC = 3.4%). Proportions of patients with thymoma, thymic carcinoma, and thymic NET were 58.9%, 38.1%, and 3.0%, respectively. For thymoma, the relative proportion of distant stage decreased (19.4% in 2005 to 8.8% in 2017) and low-grade WHO subtype (A, AB, B1) increased faster than high-grade WHO type (B2, B3) (AAPC = 19.8% versus 9.6%). For thymoma, the 5-year NS was 82.3%. This increased from 64.3% in 1999 to 2002 to 90.6% in 2013 to 2017. For thymic carcinoma, the 5-year NS was 46.2% and only slightly increased from 39.4% in 1999 to 2002 to 47.9% in 2013 to 2017.ConclusionsThis study indicates a high incidence of TET and its continuous increase in Korea. The proportion of thymic carcinoma was relatively higher than in the United States or Europe. Survival for thymoma improved during the study period, whereas this was not evident for thymic carcinoma or thymic NET.     

Thymic Carcinomas—A Concise Multidisciplinary Update on Recent Developments From the Thymic Carcinoma Working Group of the International Thymic Malignancy Interest Group

Thymic carcinomas are rare malignancies that in general arise in the prevascular (anterior) mediastinum. These tumors are usually invasive, often present at advanced stages, and typically behave aggressively. Studies are hampered by the paucity of these tumors, the large variety of carcinoma subtypes, and the lack of unique morphologic and immunophenotypic features. Despite these challenges, advances in diagnostic imaging, surgical approaches, systemic therapies, and radiation therapy techniques have been made. The WHO classification of thymic epithelial tumors has been updated in 2021, and the eighth tumor nodal metastasis staging by the American Joint Committee on Cancer/Union for International Cancer Control included thymic carcinomas in 2017. Molecular alterations that provide more insight into the pathogenesis of these tumors and that potentially permit use of novel targeted therapies are increasingly being identified. New approaches to radiation therapy, chemotherapy, and immunotherapy are under evaluation. International societies, including the International Thymic Malignancy Interest Group, European Society of Thoracic Surgeons, and Japanese, Chinese, and Korean thymic associations, have been critical in organizing and conducting multi-institutional clinical studies. Herein, we review contemporary multidisciplinary perspectives in diagnosis and management of thymic carcinoma.     

Cutaneous lymphomas—An update 2019

Primary cutaneous lymphomas (CL) are the second most common form of extranodal lymphomas. Cutaneous T‐cell lymphomas represent the majority. They are classified according to the WHO classification 2017 and the updated WHO‐EORTC 2018 published in the fourth edition of the WHO classification for Skin Tumors monograph. Primary cutaneous acral CD8+ T‐cell lymphoma and EBV‐positive mucocutaneous ulcer have been listed as new provisional entities. Moreover, the histological and genetic spectrum of lymphomatoid papulosis has been expanded. Recently, prognostic subtypes were delineated for some entities and subtypes of CL such as folliculotropic mycosis fungoides and marginal zone lymphoma. Since CL show overlapping histological features, clinico‐pathological correlation is of outmost importance for the diagnosis. Recent studies revealed new biomarkers and genetic alterations underlying the pathogenesis of CL. Moreover, targeted therapies have widened the treatment options particularly for aggressive lymphomas.     

The 2021 WHO Classification of Lung Tumors: Impact of Advances Since 2015

The 2021 WHO Classification of Thoracic Tumours was published earlier this year, with classification of lung tumors being one of the chapters. The principles remain those of using morphology first, supported by immunohistochemistry, and then molecular techniques. In 2015, there was particular emphasis on using immunohistochemistry to make classification more accurate. In 2021, there is greater emphasis throughout the book on advances in molecular pathology across all tumor types. Major features within this edition are (1) broader emphasis on genetic testing than in the 2015 WHO Classification; (2) a section entirely dedicated to the classification of small diagnostic samples; (3) continued recommendation to document percentages of histologic patterns in invasive nonmucinous adenocarcinomas, with utilization of these features to apply a formal grading system, and using only invasive size for T-factor size determination in part lepidic nonmucinous lung adenocarcinomas as recommended by the eighth edition TNM classification; (4) recognition of spread through airspaces as a histologic feature with prognostic significance; (5) moving lymphoepithelial carcinoma to squamous cell carcinomas; (6) update on evolving concepts in lung neuroendocrine neoplasm classification; (7) recognition of bronchiolar adenoma/ciliated muconodular papillary tumor as a new entity within the adenoma subgroup; (8) recognition of thoracic SMARCA4-deficient undifferentiated tumor; and (9) inclusion of essential and desirable diagnostic criteria for each tumor.     

The new World Health Organization classification of lymphomas: the past, the present and the future.

The REAL Classification of lymphomas, proposed in 1994, represents a new paradigm in lymphoma classification, consisting of a list of biologic entities defined by clinicopathologic and immunogenetic features. The non-Hodgkin's lymphomas comprise precursor lymphoblastic and mature cell neoplasms of B, T or putative natural killer cell lineage. An individual entity can exhibit a range of morphologic appearances and a range of clinical behavior. The categories in Hodgkin's lymphomas are identical to the widely used Rye classification except for the additional of a new category termed 'lymphocyte-rich classical Hodgkin's lymphoma'. The REAL classification has been validated by a major multi-institutional study involving 1378 cases (The Non-Hodgkin's Lymphoma Classification Project), showing that it is both reproducible and clinically relevant. The new World Health Organization classification of hematopoietic and lymphoid tumors, to be published in 2001, is a joint project of the Society for Hematopathology and European Association of Hematopathologists, under the auspices of the World Health Organization. This classification includes not only lymphoid neoplasms, but also myeloid, histiocytic and mast cell neoplasms. The lymphoma component of the classification is merely an update of the REAL classification, with minor changes necessitated by new information that has become available since its proposal. A conceptual grouping of the non-Hodgkin's lymphomas into four categories (indolent, aggressive, highly aggressive, and localized indolent) is also presented in this review. The next major impetus influencing the approach to lymphoma classification will no doubt be molecular genetics, in particular DNA microarrays, which will yield an enormous amount of new data that will aid in the understanding of lymphomas.     

The 2021 WHO Classification of Tumors of the Central Nervous System: a summary

The fifth edition of the WHO Classification of Tumors of the Central Nervous System (CNS), published in 2021, is the sixth version of the international standard for the classification of brain and spinal cord tumors. Building on the 2016 updated fourth edition and the work of the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy, the 2021 fifth edition introduces major changes that advance the role of molecular diagnostics in CNS tumor classification. At the same time, it remains wedded to other established approaches to tumor diagnosis such as histology and immunohistochemistry. In doing so, the fifth edition establishes some different approaches to both CNS tumor nomenclature and grading and it emphasizes the importance of integrated diagnoses and layered reports. New tumor types and subtypes are introduced, some based on novel diagnostic technologies such as DNA methylome profiling. The present review summarizes the major general changes in the 2021 fifth edition classification and the specific changes in each taxonomic category. It is hoped that this summary provides an overview to facilitate more in-depth exploration of the entire fifth edition of the WHO Classification of Tumors of the Central Nervous System.     

Is F-FDG PET useful in predicting the WHO grade of malignancy in thymic epithelial tumors? A meta-analysis

Aim

To perform a systematic review and meta-analysis of published data on the role of fluorine-18-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in predicting the WHO grade of malignancy in thymic epithelial tumors (TETs).

Methods

A comprehensive literature search of studies published up to March 2014 was performed. Data on maximum standardized uptake value (SUV_max) in patients with low-risk thymomas (A, AB, B1), high-risk thymomas (B2, B3) and thymic carcinomas (C) according to the WHO classification were collected when reported by the retrieved articles. The comparison of mean SUV_max between low-risk thymomas, high-risk thymomas and thymic carcinomas was expressed as weighted mean difference (WMD) and a pooled WMD was calculated including 95% confidence interval (95%CI).

Results

Eleven studies were selected for the meta-analysis. The pooled WMD of SUV_max between high-risk and low-risk thymomas was 1.2 (95%CI: 0.4–2.0). The pooled WMD of SUV_max between thymic carcinomas and low-risk thymomas was 4.8 (95%CI: 3.4–6.1). Finally, the pooled WMD of SUV_max between thymic carcinomas and high-risk thymomas was 3.5 (95%CI: 2.7–4.3).

Conclusions

¹⁸F-FDG PET may predict the WHO grade of malignancy in TETs. In particular, we demonstrated a statistically significant difference of SUV_max between the different TETs (low-grade thymomas, high-grade thymomas and thymic carcinomas).     

2016年版WHO淋巴肿瘤分类概述

2016年WHO淋巴肿瘤的修订版问世,内容较2008年版有些变化.文章结合过去8年内的一些临床、病理、遗传学和分子生物学的进展,阐明了一些非常早期的淋巴增生性病变的诊断和临床处理,修饰了一些淋巴瘤的诊断标准,深化了遗传学/分子生物学在多种淋巴瘤诊治中的意义.新的分类中也加入了少数临时的淋巴瘤类型.     

A Tuft Cell–Like Signature Is Highly Prevalent in Thymic Squamous Cell Carcinoma and Delineates New Molecular Subsets Among the Major Lung Cancer Histotypes

IntroductionIn-depth genomic characterization of thymic epithelial tumors (TETs), comprising thymomas and thymic carcinomas (TCs), failed to identify targetable mutations and suggested unique biology of TETs, including KIT expression in most TCs. Recently, tuft cell–like medullary thymic epithelial cells were identified in the murine thymus, and our reanalysis of the published gene expression data revealed that these cells express KIT. In addition, recently, a minor subset of SCLCs with tuft cell–like features was described.MethodsWe interrogated mRNA expression data from our tumor cohorts (N = 60) and publicly available, independent data sets from TETs and NSCLC (N = 1199) for expression of tuft cell genes and KIT. Expression of KIT and of POU2F3 protein, the master regulator of tuft cells, was analyzed in cancer tissue (N = 344) by immunohistochemistry.ResultsNormal human thymic tuft cells and most TCs coexpressed KIT and known tuft cell genes, particularly POU2F3 and GFI1B. Unexpectedly, small subsets of tuft cell–like tumors coexpressing POU2F3, GFI1B, and KIT were also identified among pulmonary squamous cell carcinomas, adenocarcinomas, and large cell neuroendocrine carcinoma and clustered together in each histologic cohort. In addition to the tuft cell–like signature, both thymic and lung tuft cell–like carcinomas had distinct genetic, pathologic, and clinical features in each cohort.ConclusionsWe suggest that the tuft cell–like phenotype defines novel subsets of thymic and pulmonary carcinoma. Its high prevalence in thymic squamous cell carcinomas that have no known toxic or viral etiologies suggests a new mechanism of carcinogenesis that may lead to specific drug susceptibilities.     

组织细胞肿瘤的重新认识、分类与临床特征

细胞免疫组织化学及分子遗传学技术的发展,对以往诊断为恶性组织细胞增多症、组织细胞性淋巴瘤等组织细胞肿瘤,进行了重新认识,并证明大多数病例为T细胞、NK细胞或B细胞淋巴瘤以及噬血细胞综合征。本文介绍新的WHO组织细胞/树突状细胞肿瘤分类、形态学和免疫组织化学的诊断要点、临床表现特征、治疗及预后。噬血细胞综合征是非肿瘤性、巨噬细胞增殖、活化伴有噬血细胞吞噬现象的临床病理综合征,并介绍了噬血细胞综合征的分类、诊断标准和治疗原则。重新认识组织细胞和树突状细胞肿瘤将有助于提高本病的诊治水平、改善预后。     

The World Health Organization histologic classification system reflects the oncologic behavior of thymoma: a clinical study of 273 patients

BACKGROUND: Although the histologic classification of thymic epithelial tumors has been confusing and controversial, an agreement on the universal classification system for thymic epithelial tumors was achieved by the World Health Organization (WHO) in 1999. The authors previously reported that the WHO histologic classification system reflects invasiveness and immunologic function of thymic epithelial tumors. In this subsequent study, they examined the prognostic significance of this classification system. METHODS: Clinical features as well as postoperative survival of patients with thymoma, but not thymic carcinoma, were examined with reference to WHO histologic classification based on an experience with 273 patients over a 44-year period. RESULTS: There were 18 type A tumors, 77 type AB tumors, 55 type B1 tumors, 97 type B2 tumors, and 26 type B3 tumors. In patients with type A, AB, B1, B2, and B3 tumors, the respective proportions of invasive tumor were 11.1%, 41.6%, 47.3%, 69.1%, and 84.6%; the respective proportions of tumors with involvement of the great vessels were 0%, 3.9%, 7.3%, 17.5%, and 19.2%; and the respective 20-year survival rates were 100%, 87%, 91%, 59%, and 36%. According to the Masaoka staging system, the 20-year survival rates were 89%, 91%, 49%, 0%, and 0% in patients with Stage I, II, III, IVa, and IVb disease, respectively. By multivariate analysis, the Masaoka staging system and the WHO histologic classification system were significant independent prognostic factors, whereas age, gender, association with myasthenia gravis, completeness of resection, or involvement of the great vessels were not significant independent prognostic factors. CONCLUSIONS: This study showed that histologic appearance reflects the oncologic behavior of thymoma when the WHO classification system is adopted. The WHO classification system may be helpful in clinical practice for the assessment and treatment of patients with thymoma.     

Cutaneous T-cell lymphoma: epidemiology, etiology, and classification

The term cutaneous T-cell lymphoma (CTCL) describes a heterogeneous group of neoplasms of skin-homing T-cells that vary considerably in clinical presentation, histologic appearance, immunophenotype, and prognosis. CTCL represent approximately 75-80% of all primary cutaneous lymphomas, whereas primary cutaneous B cell lymphomas account for approximately 20-25%. For many years mycosis fungoides and Sézary's syndrome were the only known types of CTCL. In the last decade, based on a combination of clinical, histological, and immunophenotypical criteria, new types of CTCL have been defined and new classifications for this group of primary cutaneous lymphomas have been formulated. In this overview, characteristic features of the different types of CTCL recognized in the European Organization for Research and Treatment of Cancer (EORTC) classification for primary cutaneous lymphomas and the World Health Organization (WHO) classification will be reviewed. Key conclusions from this brief overview are: (1) that the term CTCL does not refer to a single disease entity, but to a group of diseases with different clinical behaviors, therapeutic requirements, and prognoses; (2) that diagnosis and classification should always be based on a combination of clinical, histologic, and immunologic criteria; and (3) that the WHO and EORTC classification schemes are broadly equivalent for almost 90% of CTCL patients. Key research priorities are to develop effective therapies for peripheral T-cell lymphoma, extranodal NK (natural killer) T-cell lymphoma and so-called blastic NK cell lymphoma, and to determine molecular profiles for all forms of CTCL.     

微小RNAs对胸腺上皮细胞肿瘤的影响及研究进展

胸腺作为机体重要免疫器官,参与机体多种免疫功能。胸腺瘤和胸腺癌是来源于胸腺上皮细胞的肿瘤,在我国前纵隔肿瘤中较为常见。微小RNA（microRNAs,miRNAs）是一类内源性非编码小分子单链RNA,长度约为22个氨基酸,参与转录后基因表达调控过程。近年来miRNAs的研究已成为各学科的研究热点,针对miRNAs的新型诊断方法与治疗手段不断在国内外学术期刊上报道。胸腺上皮细胞肿瘤由于常伴有副肿瘤综合征,使其在临床症状表现及治疗方面复杂多样,通过miRNAs与胸腺上皮细胞肿瘤的研究,有望从根源上找出胸腺肿瘤多样性的原因并找到有效治疗手段。本文对近几年miRNAs与胸腺上皮细胞肿瘤的研究进行文献复习,探讨miRNAs对胸腺上皮细胞肿瘤的影响及研究进展,并作一综述。     

Tumeurs épithéliales thymiques : actualités dans la prise en charge en France

Thymic epithelial neoplasms are rare malignancies with about 250 new incident cases in France every year. The WHO histologic classification distinguishes thymoma and thymic carcinoma which are tumors with different biological and clinical behaviors and outcomes. The Masaoka-Koga staging system is considered as a reference and is also of prognosis value. Diagnosis, multimodal treatment and follow-up of thymic epithelial neoplasms require a multidisciplinary approach where surgery is the cornerstone treatment. A national expert center coordinates thymic epithelial neoplasms management with 12 other regional expert centers through the French organization named RYTHMIC (www.rythmic.org). Patient's files have to be discussed at regional or national multidisciplinary staff. A group of expert pathologists will centrally review tumors when the diagnosis or classification is a matter of controversy. Among its objectives, RYHTMIC has to promote medical education, patient's information and research. This review focuses on RYTHMIC guidelines and data regarding multimodal management and targeted therapies in epithelial thymic neoplasms.     

The 2015 World Health Organization Classification of Lung Tumors: Impact of Genetic,Clinical and Radiologic Advances Since the 2004 Classification

The 2015 World Health Organization (WHO) Classification of Tumors of the Lung, Pleura, Thymus and Heart has just been published with numerous important changes from the 2004 WHO classification. The most significant changes in this edition involve (1) use of immunohistochemistry throughout the classification, (2) a new emphasis on genetic studies, in particular, integration of molecular testing to help personalize treatment strategies for advanced lung cancer patients, (3) a new classification for small biopsies and cytology similar to that proposed in the 2011 Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification, (4) a completely different approach to lung adenocarcinoma as proposed by the 2011 Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification, (5) restricting the diagnosis of large cell carcinoma only to resected tumors that lack any clear morphologic or immunohistochemical differentiation with reclassification of the remaining former large cell carcinoma subtypes into different categories, (6) reclassifying squamous cell carcinomas into keratinizing, nonkeratinizing, and basaloid subtypes with the nonkeratinizing tumors requiring immunohistochemistry proof of squamous differentiation, (7) grouping of neuroendocrine tumors together in one category, (8) adding NUT carcinoma, (9) changing the term sclerosing hemangioma to sclerosing pneumocytoma, (10) changing the name hamartoma to “pulmonary hamartoma,” (11) creating a group of PEComatous tumors that include (a) lymphangioleiomyomatosis, (b) PEComa, benign (with clear cell tumor as a variant) and (c) PEComa, malignant, (12) introducing the entity pulmonary myxoid sarcoma with an EWSR1–CREB1 translocation, (13) adding the entities myoepithelioma and myoepithelial carcinomas, which can show EWSR1 gene rearrangements, (14) recognition of usefulness of WWTR1–CAMTA1 fusions in diagnosis of epithelioid hemangioendotheliomas, (15) adding Erdheim–Chester disease to the lymphoproliferative tumor, and (16) a group of tumors of ectopic origin to include germ cell tumors, intrapulmonary thymoma, melanoma and meningioma.     

MSCT征象联合纹理分析在预测胸腺上皮性肿瘤WHO简化病理分型中的价值

背景与目的：胸腺上皮性肿瘤（thymic epithelial tumor,TET）是前上纵隔最常见的原发肿瘤,其组织学分型是判断预后的独立危险因素。探讨和比较术前多层螺旋计算机断层扫描（multi-slice spiral computed tomography,MSCT）征象及基于CT图像的纹理分析在预测TET世界卫生组织（World Health Organization,WHO）简化病理分型中的价值。方法：回顾并分析2011年1月—2018年6月复旦大学附属肿瘤医院手术后经病理学检查证实为TET、且经免疫组织化学确定组织分型的120例患者的增强CT图像及临床资料,并根据WHO简化病理分型分为低危组（A1、AB、B1型胸腺瘤）及高危组（B2、B3型胸腺瘤及胸腺癌）。评估及记录每例TET患者的CT征象。选用纵隔窗CT图像进行病灶分割及纹理特征的提取。采用R软件套索（least absolute shrinkage and selection operator,Lasso）模型进行特征筛选及模型建立。采用受试者工作特征 （receiver operating characteristic,ROC）曲线和曲线下面积（area under curve,AUC）评价模型的预测效能。不同预测模型之间诊断效能的比较采用DeLong检验。结果：120例TET患者中低危组61例,高危组59例,分别记录及提取了每例患者CT图像的11种CT征象和14种纹理特征。分别建立了以MSCT征象、纹理参数以及两者联合为基础的CT预测模型、纹理预测模型以及联合预测模型,3个模型在预测低危组及高危组TET的AUC分别为0.78、0.80、0.88,灵敏度分别为86.4%、88.1%和93.2%,特异度分别为60.7%、65.6%和67.2%,准确率分别为70.8%、74.2%和80.0%。DeLong检验结果显示,联合预测模型在预测TET恶性程度中的效能及准确率最高（P<0.05）。结论：MSCT检查是TET首选的影像学检查方法,纹理特征比肉眼评估得到的CT征象更能反映TET的微观异质性程度,CT征象与纹理特征相结合在预测TET恶性程度中更有优势,可为临床制订治疗方案及评估预后提供更全面及准确的依据。     

Diagnostic and clinical significance of KIT(CD117) expression in thymic epithelial tumors in China

Aims: To study KIT (CD117) expression in thymic epithelial tumors in China, and investigate diagnosticand clinical significance. Material and Methods: Thymic epithelial tumors (TETs) from 102 patients (3 type A,29 type AB, 5 type B1, 22 type B2, 29 typeB3 and 16 thymic carcinomas) were examined. Immunohistochemicalstaining with an antic-kit monoclonal antibody was performed on a tissue microarray. Relationships betweenKIT positive expression and the TET clinical characteristics (WHO histologic classification and Masaoka stagesystem) were analysed. Results: The KIT positive expression rate was significantly higher in thymic carcinoma(60%, 9/16) than in thymoma (8%, 7/86), a strong correlation being found with the WHO classification, but notthe Masaoka tumor stage. The overall survival for patients with KIT positive lesions was significantly worse.Conclusions: KIT is a good molecule marker to differentially diagnose thymic carcinoma from thymoma, whilealso serving as a predictor of prognosis for TETs. Further research into KIT mutations in Chinese TETs shouldbe conducted to assess the efficacy of targeted therapy.