摘要目的:探讨肺动脉内膜肉瘤（PAIS）的病理形态、基因特征及鉴别诊断。方法:分析江苏省人民医院2016年2月至2019年11月确诊的3例PAIS，总结其临床及影像学资料、组织病理学特征、免疫组织化学表型及分子遗传学改变。结果:男性1例，女性2例；年龄分别为32、50、60岁；症状表现为不同程度的咳嗽、胸闷气喘；影像学示低密度充盈缺损，拟诊为血栓或栓塞性疾病、黏液瘤可能。大体上肿瘤主体位于肺动脉主干及其分支内，延伸至心房、心室，小灶区侵犯周围肺实质；组织学示梭形细胞肉瘤，黏液背景中的肿瘤细胞形态类似于纤维母细胞或肌纤维母细胞，可见明显异型性、核分裂象及灶性坏死；免疫组织化学缺乏特异性标志物，肿瘤细胞波形蛋白阳性，广谱细胞角蛋白（CKpan）、S-100蛋白、结蛋白、Fli-1、CD31、平滑肌肌动蛋白（SMA）、ERG不同程度阳性；荧光原位杂交（FISH）检测3例均显示MDM2扩增，2例示表皮生长因子受体（EGFR）基因扩增。随访：1例分别于18、32、42个月出现胰腺+脾脏、胃体及肝脏转移，2例术后未见复发或转移。结论:PAIS是起自弹性肺动脉内膜的恶性间叶性肿瘤，形态学未见明确分化特征，基因检测发现MDM2、EGFR扩增。该肿瘤预后极差，手术彻底切除是短期缓解的唯一有效治疗方式，放化疗的作用尚有争议。

abstractsObjective:To investigate the clinicopathological characteristics, genetic features, diagnosis and differential diagnosis of pulmonary artery intimal sarcoma (PAIS).Methods:Three cases of PAIS were collected from Jiangsu Province People′s Hospital (from February 2016 to November 2019). The clinical data, imaging examination, morphology, immunostaining, and molecular changes were retrospectively analyzed.Results:There were 1 male and 2 females (age: 32, 50, 60 years), who had symptoms of cough, asthma or chest tightness. Imaging findings indicated low density filling defects which were suspected as thrombus, embolism or myxoma. Grossly, the main tumor was located in the elastic arteries and their lobar branches, also extended into the atrium and ventricle, with lung parenchymal infiltration focally. Microscopically, tumor cells were predominantly composed of abundant spindle cells with obvious atypia and myxoid background, resembling fibroblastic or myofibroblastic differentiation. Active mitotic figures and necrosis could be seen in some areas. Immunohistochemical staining of vimentin was strongly positive, while pan-cytokeratin, S-100, desmin, Fli-1, CD31, SMA and ERG etc were variably positive only in focal areas. FISH detection showed amplification of MDM2 gene in three cases and EGFR gene in two cases. Metastatic lesions were found in one case by 18, 32 and 42 months after surgery respectively. There was no recurrence or metastasis in the other two cases.Conclusions:PAIS is one of exceptionally poor differentiated mesenchymal tumor that arises from the arterial intima of elastic pulmonary arteries. There was no definite differention in morphology. Gene detection shows amplification of MDM2 and EGFR gene. This tumor often has poor prognosis with aggressive behavior. Complete resection is the only effective therapeutic option. There is disagreement as to whether chemotherapy and radiotherapy can improve survival.