PET/CT表现为高代谢的肺部空洞病灶两例分析

Analysis of two cases presenting with hypermetabolic cavitary lung lesions on PET/CT

IgG4相关性肺疾病(IgG4-RLD)是一种以活性IgG4阳性浆细胞和淋巴细胞浸润肺组织所致的疾病,在正电子发射型计算机体层摄影术/计算机体层扫描(PET/CT)上常表现为^(18)氟代脱氧葡萄糖(^(18)F-FDG)高摄取。该病在CT影像学上可呈多种表现,但空洞型病灶是一种罕见的表现,需与空洞型肺癌鉴别。该文报道2例临床和影像学表现均相似的空洞型肺疾病,其在PET/CT上均呈^(18)F-FDG高摄取,最终病理结果显示其中一例诊断为IgG4-RLD,而另一例则诊断为肺癌。该文提示,血清IgG4增高及结节状^(18)F-FDG高摄取是鉴别IgG4-RLD和肺癌的重要特征。

IgG4-related lung disease （IgG4-RLD） is a disease caused by the infiltration of IgG4-positive plasma cells and lymphocytes into lung tissues, which is manifested with high uptake of 18F-fluorodeoxyglucose （18F-FDG） on positron emission tomography/computed tomography （PET/CT）.IgG4-RLD yields multiple forms of radiologic features on CT imaging.However, cavitary mass is a rare imaging feature and should be differentially diagnosed from cavitary malignant tumor.In this article, we reported two cases presenting with similar clinical and imaging signs to cavitary pulmonary disease with high uptake of 18F-FDG on PET/CT.One patient was eventually diagnosed with IgG4-RLD and the other case was diagnosed with lung cancer by pathological biopsy.The findings in this article prompt that elevated serum level of IgG4 and high uptake of 18F-FDG are vital features to differentially diagnose from IgG4-RLD to lung cancer.