Department of Radiology, Division of Nuclear Medicine, Jackson Memorial Hospital, University of Miami and Miller School of Medicine, 1080 NW 19th Street, Miami, FL 33136, USA.
Radiographics. 2010 Jan;30(1):269-91. doi: 10.1148/rg.301095088.
The term extranodal disease refers to lymphomatous infiltration of anatomic sites other than the lymph nodes. Almost any organ can be affected by lymphoma, with the most common extranodal sites of involvement being the stomach, spleen, Waldeyer ring, central nervous system, lung, bone, and skin. The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease has increased in the past decade. The imaging characteristics of extranodal involvement can be subtle or absent at conventional computed tomography (CT). Imaging of tumor metabolism with 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) has facilitated the identification of affected extranodal sites, even when CT has demonstrated no lesions. More recently, hybrid PET/CT has become the standard imaging modality for initial staging, follow-up, and treatment response assessment in patients with lymphoma and has proved superior to CT in these settings. Certain PET/CT patterns are suggestive of extranodal disease and can help differentiate tumor from normal physiologic FDG activity, particularly in the mucosal tissues, bone marrow, and organs of the gastrointestinal tract. Familiarity with the different extranodal manifestations in various locations is critical for correct image interpretation. In addition, a knowledge of the differences in FDG avidity among the histologic subtypes of lymphoma, appropriate timing of scanning after therapeutic interventions, and use of techniques to prevent brown fat uptake are essential for providing the oncologist with accurate information.
“结外疾病”一词是指淋巴结以外的解剖部位的淋巴瘤浸润。几乎任何器官都可能受到淋巴瘤的影响，最常见的结外受累部位是胃、脾、Waldeyer 环、中枢神经系统、肺、骨和皮肤。在过去十年中，非霍奇金淋巴瘤和霍奇金病的结外受累的患病率有所增加。常规计算机断层扫描（CT）可能无法显示结外受累的细微或不存在的影像学特征。使用 2-[氟-18]氟-2-脱氧-d-葡萄糖（FDG）正电子发射断层扫描（PET）对肿瘤代谢成像有助于识别受累的结外部位，即使 CT 未显示病变。最近，混合 PET/CT 已成为淋巴瘤患者初始分期、随访和治疗反应评估的标准成像方式，并且在这些情况下优于 CT。某些 PET/CT 模式提示结外疾病，并有助于将肿瘤与正常生理 FDG 活性区分开来，尤其是在黏膜组织、骨髓和胃肠道器官中。熟悉各种部位的不同结外表现对于正确的图像解释至关重要。此外，了解淋巴瘤不同组织学亚型之间的 FDG 摄取差异、在治疗干预后进行扫描的适当时间以及使用预防棕色脂肪摄取的技术对于向肿瘤学家提供准确的信息也是必不可少的。
