原发性肺淋巴瘤的CT表现、病理特征与误诊分析

The Study of CT Findings of Primary Pulmonary Lymphoma and Correlation with Pathological and Immunohistochemical Features

目的研究原发性肺淋巴瘤的CT表现,并结合病理、免疫组织化学特征,以期提高对该病的认识及诊断能力。方法回顾性分析8例最终证实的原发性肺淋巴瘤的CT表现,其中7例行平扫加增强扫描,1例仅行增强扫描。结果 CT扫描表现为肺的单发肿块3例,1例可见支气管充气征,2例可见间质浸润征,误诊为炎性病变1例,误诊为周围型肺癌2例;多发肿块1例,可见间质浸润征和跨叶分布征,误诊为中央型肺癌合并肺转移;实变型3例,其中单纯实变型1例,实变型合并结节型2例,3例均可见充气支气管征,2例可见支气管扩张症,2例可见血管造影征,1例可见跨叶分布征,误诊为大叶性肺炎1例,中央型肺癌合并肺转移1例,支气管内膜结核1例;多发结节型1例,可见间质浸润征,误诊为肉芽肿性病变。7例中,轻度强化1例,中度强化2例,明显强化4例。病理组织学表现为淋巴瘤细胞沿肺内淋巴道或支气管、血管周围间隙浸润生长,免疫组织化学标记物中阳性表达较高者为LCA和CD79α。结论原发性肺淋巴瘤是一种少见病,临床症状及CT表现缺乏特征性,易误诊。瘤内或实变影中出现充气支气管征,同时合并支气管扩张症和/或血管造影征,肿块、结节周围间质浸润的出现以及没有肺门、纵隔淋巴结肿大,可提示本病的可能,最终确诊须结合肺活检或手术病理及免疫组织化学检查。

Objective To study CT findings and related pathological and immunohistochemical features of primary pulmonary lymphoma, and improve its diagnostic accuracy. Methods CT findings of 8 cases with pathologically and immunohistochemically proven primary pulmonary lymphoma were analyzed retrospectively. Seven patients underwent plain and enhanced chest CT scan and one was performed enhanced chest scan only. Results Chest CT scan revealed solitary mass in 3 cases, air bronchogram in 1 case and interstitial infiltration in 2 cases. Of these three patients, one case was misdiagnosed as inflammatory lesion and the other two cases were misdiagnosed as peripheral lung cancer. CT scan depicted multiple masses in 1 case with diffuse interstitial infiltration extending over interlobar fissure, without zonal predominance, which was misdiagnosed as central lung cancer with pulmonary metastases. Air space consolidation with or without lung nodules were seen in 3 cases, coexisted bronchiectasis and ＂angiogram sign＂ were observed in 2 cases and the mass extending over interlohar fissure in 1 case, which leading to two patients misdiagnosed as central lung cancer with pulmonary metastases, one as lobar pneumonia and the other as endobronchial tuberculosis respectively. CT demonstrated multiple nodules with interstitial infiltration in one case, which was misdiagnosed as granulomatous lesions. On enhanced CT scans the lesions showed mild enhancement in 1 case, moderate enhancement in 2 cases and obvious enhancement in 4 cases. Histologically, they were characterized by lymphoma cells infiltration along the lymphatic channels or peribronchial/perivaseular spaces. Immunohistochemical staining demonstrated that LCA（6/6） 和CD79α（5/5） had relatively high positive expression rate. Conclusion Primary lymphoma of the lung is rare. CT can not provide a definitive diagnosis due to nonspecific clinical and CT findings. However, it is supposed that the possibility of primary pulmonary lymphoma should be considered when air space consolidation with air bronehogram and/or ＂angiogram sign＂ , nodule/nodules with interstitial infiltration and no mediastinal or hilar adenopathy are observed on chest CT scan. Final diagnosis should depend on percutaneous or surgical lung biopsy and immunobistochemical examination.