胸腺上皮性肿瘤的MRI表现

胸腺上皮性肿瘤的MRI表现

MR Imaging of Thymic Epithelial Neoplasms

综述：

胸腺上皮肿瘤是起源于胸腺的恶性病变，包括胸腺瘤、胸腺癌和胸腺神经内分泌肿瘤。尽管计算机断层扫描（CT）通常被认为是鉴别胸腺肿瘤、评估原发肿瘤和疾病分期的首选成像方式，但磁共振（MR）成像的作用得到了很大拓展。MRI能有效区分胸腺上皮性肿瘤和其他恶性肿瘤与血管前纵隔良性病变，可用于CT增强禁忌症患者胸腺肿瘤的定性和分期，并能显示胸腺肿瘤的形态学特征。胸腺上皮肿瘤至少有15种不同的分期，并在临床实践中得到不同程度的应用。最近，美国癌症联合委员会（AJCC）和国际癌症控制联盟（UICC）认可了一个正式的、一致的肿瘤转移分期系统，基于国际肺癌研究协会（IASLC）和国际胸腺恶性肿瘤兴趣小组（ITMIG）的回顾性数据库分析。本文讨论了MRI在胸腺上皮性肿瘤诊断中的应用，肿瘤的主要影像学特征，以及影像学表现对整体分期的影响。

Abstract

Thymic epithelial neoplasms are malignant lesions that originate from the thymus and include thymoma, thymic carcinoma, and thymic neuroendocrine tumors. Although computed tomography (CT) is typically considered the imaging modality of choice for identifying thymic tumors, characterizing the primary neoplasm, and staging of disease, the role of magnetic resonance (MR) imaging continues to expand. MR imaging is effective in distinguishing thymic epithelial neoplasms and other malignant tumors from benign lesions in the prevascular mediastinum, can be used to characterize and stage thymic tumors in those patients with contraindications to contrast-enhanced CT, and can reveal morphologic features of thymic tumors. At least 15 different stage classifications have been proposed for thymic epithelial neoplasms and used to varying degrees in clinical practice. Recently, an official, consistent tumor node metastasis (TNM) staging system has been recognized by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC), based on an analysis of a retrospective database performed by the International Association for the Study of Lung Cancer (IASLC) and the International Thymic Malignancy Interest Group (ITMIG). In this article, we discuss the appropriate utilization of MR imaging in the evaluation of patients with thymic epithelial neoplasms, key imaging features of the tumors, and the impact of imaging findings on overall staging.