Ishizuka Kosuke, Shikino Kiyoshi, Yokokawa Daiki, Ikusaka Masatomi
Department of General Medicine, Chiba University Hospital, Japan.
Radiol Case Rep. 2021 Aug 1;16(10):2886-2889. doi: 10.1016/j.radcr.2021.07.008. eCollection 2021 Oct.
Follicular lymphoma is clinically classified as a common type of indolent non-Hodgkin's lymphoma, and its clinical diagnosis is difficult because B symptoms and elevated soluble interleukin-2 receptor (sIL-2R) levels are less frequent in follicular lymphoma than in other lymphomas. We report a case of follicular lymphoma masquerading immunoglobulin G4-related disease (IgG4-RD) with elevated IgG4 levels. A 67-year-old man presented to our hospital with a 1-year history of deep right supraclavicular and para-aortic lymph node lymphadenopathy on plain computed tomography (CT) findings along with elevated IgG4 levels, and the F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scan showed heterogeneous diffuse FDG uptake in the liver, and FDG uptake was noted at multiple sites in the enlarged right supraclavicular and para-aortic lymph nodes. Excisional biopsy of the right supraclavicular lymph node, performed under general anesthesia, showed a tumor-like structure mimicking a normal germinal center in the lymphoid follicle; immunostaining was positive for B-cell lymphoma 2 and CD10 proteins with some plasma cells stained with IgG, only 30% of them were positive for IgG4, and no marked fibrosis characteristic of IgG4-RD was observed; therefore, follicular lymphoma was diagnosed, and all symptoms, including FDG uptake, improved with rituximab monotherapy. Differential diagnoses of slowly progressive generalized lymphadenopathy over the years with elevated serum IgG4 levels include IgG4-RD, Castleman's disease, and indolent lymphoma. Multiple accumulation in the liver on FDG-PET/CT, if found, may suggest indolent lymphoma among them.
滤泡性淋巴瘤在临床上被归类为一种常见的惰性非霍奇金淋巴瘤，由于与其他淋巴瘤相比，B症状和可溶性白细胞介素-2受体（sIL-2R）水平升高在滤泡性淋巴瘤中较少见，因此其临床诊断较为困难。我们报告一例伪装成免疫球蛋白G4相关疾病（IgG4-RD）且IgG4水平升高的滤泡性淋巴瘤病例。一名67岁男性因右锁骨上深部和主动脉旁淋巴结肿大1年就诊于我院，普通计算机断层扫描（CT）检查发现有淋巴结病，同时IgG4水平升高，氟脱氧葡萄糖（FDG）正电子发射断层扫描/计算机断层扫描（PET/CT）显示肝脏有不均匀弥漫性FDG摄取，在肿大的右锁骨上和主动脉旁淋巴结多个部位也有FDG摄取。在全身麻醉下对右锁骨上淋巴结进行切除活检，显示肿瘤样结构，模仿淋巴滤泡中的正常生发中心；免疫染色显示B细胞淋巴瘤2和CD10蛋白呈阳性，部分浆细胞被IgG染色，其中只有30%对IgG4呈阳性，未观察到IgG4-RD特有的明显纤维化；因此，诊断为滤泡性淋巴瘤，包括FDG摄取在内的所有症状在利妥昔单抗单药治疗后均得到改善。多年来血清IgG4水平升高且缓慢进展的全身性淋巴结病的鉴别诊断包括IgG4-RD、卡斯尔曼病和惰性淋巴瘤。如果在FDG-PET/CT上发现肝脏有多处积聚，可能提示其中存在惰性淋巴瘤。
