Peng Ying, Qi Wanling, Luo Zhehuang, Zeng Qingyun, Huang Yujuan, Wang Yulu, Sharma Amit, Schmidt-Wolf Ingo G H, Liao Fengxiang
Department of Cardiology, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China.
Department of Nuclear Medicine, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China.
Front Oncol. 2022 Sep 14;12:973109. doi: 10.3389/fonc.2022.973109. eCollection 2022.
Primary pulmonary lymphoma (PPL) is defined as clonal abnormal hyperplasia of lung parenchyma or bronchial lymphoid tissue originating from bronchial mucosal tissue. However, PPL is rare, which accounts for approximately 3-4% of extraneurotic lymphomas and 0.5-1% of all primary tumors in the lung. Owing to the lack of any typical clinical symptoms and radiological features, it is challenging to accurately diagnose PPL, which affects its clinical management and prognosis. Considering this, herein, we aim to raise awareness of this disease and help physicians understand the role of 18F-FDG PET/CT in the diagnosis of PPL.
A retrospective analysis was performed on the clinical and 18F-FDG PET/CT imaging data of 19 patients diagnosed with PPL by biopsy pathology at our hospital from April 2014 to December 2021.
Of the 19 PPL patients, 15 patients showed clinical symptoms with the most common being fever and cough. In addition, there were 4 cases that had no clinical symptoms, and all of them were MALT lymphoma. In fact, 16 patients were misdiagnosed as lobar pneumonia, lung cancer, tuberculosis, and diffuse interstitial inflammation, representing a misdiagnosis rate of 84.2%. Also, 73.7% were MALT lymphomas, representing the most common pathological pattern, along with 3 DLBCL and 2 T-cell lymphomas. With reguard to CT signs, the air-bronchial sign was found to be the most common, followed by the halo sign and the collapsed leaf sign. On the basis of the predominant radiologic features, lesions were categorized as pneumonic consolidation, nodular/mass type, diffuse interstitial type, and mixed type. The average SUVmax of lesions was 7.23 ± 4.75, the ratio of SUVmax (lesion/liver) was 3.46 ± 2.25, and the ratio of SUVmax (lesion/mediastinal blood pool) was found to be 5.25 ± 3.27. Of interest, the different pathological types of PPL showed different values of 18F-FDG uptake. The 18F-FDG uptake of DLCBL was the most prominent with a SUVmax of 15.33 ± 6.30 and was higher than that of MALT lymphoma with a SUVmax of 5.74 ± 2.65. There appeared similarity in 18F-FDG uptake between MALT lymphoma and T-cell lymphoma. For the SUVmax of lesion, we found statistical significance between MALT lymphoma and DLCBL (P value<0.001). In addition, we also found statistical significance (P value < 0.05) in SUVmax of lesions between pneumonic consolidation type and nodal/mass type, I stage, and other stages.
On 18F-FDG PET/CT images, certain features of PPL morphology and metabolism can be identified that may contribute to a better understanding of this disease. In addition, 18F-FDG PET/CT whole-body imaging has the potential to refine the staging of PPL. Most importantly, functional 18F-FDG PET/CT imaging can readily reflect tumor cell activity, thus allowing for the selection of an optimal biopsy site.
原发性肺淋巴瘤（PPL）被定义为起源于支气管黏膜组织的肺实质或支气管淋巴组织的克隆性异常增生。然而，PPL较为罕见，约占结外淋巴瘤的3 - 4%，占所有原发性肺部肿瘤的0.5 - 1%。由于缺乏任何典型的临床症状和影像学特征，准确诊断PPL具有挑战性，这影响了其临床管理和预后。考虑到这一点，在此我们旨在提高对该疾病的认识，并帮助医生了解18F - FDG PET/CT在PPL诊断中的作用。
对2014年4月至2021年12月在我院经活检病理确诊为PPL的19例患者的临床及18F - FDG PET/CT影像资料进行回顾性分析。
19例PPL患者中，15例有临床症状，最常见的是发热和咳嗽。此外，有4例无临床症状，均为黏膜相关淋巴组织（MALT）淋巴瘤。实际上，16例患者被误诊为大叶性肺炎、肺癌、肺结核和弥漫性间质性炎症，误诊率为84.2%。同时，73.7%为MALT淋巴瘤，是最常见的病理类型，还有3例弥漫大B细胞淋巴瘤（DLBCL）和2例T细胞淋巴瘤。关于CT征象，空气支气管征最常见，其次是晕征和肺叶萎陷征。根据主要影像学特征，病变分为肺炎实变型、结节/肿块型、弥漫间质型和混合型。病变的平均最大标准摄取值（SUVmax）为7.23±4.75，SUVmax（病变/肝脏）比值为3.46±2.25，SUVmax（病变/纵隔血池）比值为5.25±3.27。有趣的是，不同病理类型的PPL显示出不同的18F - FDG摄取值。DLBCL的18F - FDG摄取最显著，SUVmax为15.33±6.30，高于MALT淋巴瘤的SUVmax（5.74±2.65）。MALT淋巴瘤和T细胞淋巴瘤在18F - FDG摄取方面表现出相似性。对于病变的SUVmax，我们发现MALT淋巴瘤和DLBCL之间具有统计学意义（P值<0.001）。此外，我们还发现肺炎实变型与结节/肿块型、Ⅰ期和其他期之间病变的SUVmax也具有统计学意义（P值<0.05）。
在18F - FDG PET/CT图像上，可以识别出PPL形态和代谢的某些特征，这可能有助于更好地理解该疾病。此外，18F - FDG PET/CT全身成像有潜力完善PPL的分期。最重要的是，功能性18F - FDG PET/CT成像能够很容易地反映肿瘤细胞活性，从而有助于选择最佳活检部位。
