中央气道原发涎腺型肿瘤的影像表现及预后分析

The imaging features and prognosis of primary central airway salivary gland-type tumor

目的探讨中央气道原发涎腺型肿瘤(SGT)的影像表现及预后特点,以提高对该病的认识。方法回顾性分析2009年10月至2017年11月本院经病理证实的25例中央气道原发SGT的临床及影像资料,并随访统计患者生存率。依据病理结果分为腺样囊性癌(ACC)14例(ACC组),黏液表皮样癌(MEC)10例(MEC组),上皮肌上皮癌(EMC)1例。患者术前均行CT检查及MPR后处理,其中CT增强扫描20例;PET-CT检查8例;MR检查1例。观察并记录肿瘤CT征象。采用独立样本t检验比较ACC组与MEC组患者年龄的差异。采用非参数检验比较两组病灶最大径的差异。采用Fisher精确概率法比较两组患者性别、吸烟史、TNM分期及CT征象的差异。采用Kaplan-Meier法估计总生存率(OS),采用log-rank方法比较两组患者OS的差异。结果ACC组患者发病年龄大于MEC组,差异有统计学意义(t=3.154,P<0.05)。ACC多位于气管或主支气管(13/14),MEC多位于叶或段支气管(6/10);ACC形态以分叶状肿块或管壁弥漫性增厚为主(13/14),MEC多表现为表面光滑的类椭圆形肿块(7/10);CT增强扫描ACC以轻中度强化为主(9/10),MEC多显著强化(8/10);MEC伴气道阻塞征象(9/10)较ACC(4/14)常见;ACC组与MEC组以上CT征象的差异均有统计学意义(P值均<0.05)。1例EMC表现为气管腔内类圆形结节。8例PET/CT检查中6例SUVmax≥2.2。25例患者中,1例失随访,其余患者随访时间2个月~9年(平均45个月),OS为87.5%;ACC组与MEC组患者OS的差异无统计学意义(χ^2=0,P=1.000)。年龄≤60岁、临床TNM分期为Ⅰ~Ⅱ期、行手术切除的患者OS高于年龄>60岁、临床TNM分期为Ⅲ~Ⅳ期、非手术切除的患者(χ^2值分别为13.799、13.799、13.171,P值均<0.05)。结论中央气道原发SGT浸润性弱,患者年龄偏低且预后良好,ACC与MEC的病灶部位、形状、强化程度及是否伴气道阻塞征象有差异。

Objective To analyze the image features and prognosis of primary central airway salivary gland-type tumor (SGT). Methods The clinical and imaging data of 25 cases with SGT confirmed by histopathology were retrospectively analyzed in our hospital from October 2009 to November 2017. Follow up of patients for survival was performed. Among 25 cases of SGT, there were 14 cases of adenoid cystic carcinoma (ACC), ten cases of mucoepidermoid carcinoma (MEC) and one case of mucoepidermoid carcinoma (EMC). All cases had non-enhanced CT scans (among which 20 cases underwent CT scan with contrast). Post-processing were performed to evaluate the location, range, density, degree of enhancement of the lesions and involvement of hilar or mediastinal lymph nodes. Eight cases underwent PET/CT imaging and one underwent MR imaging, respectively. Independent sample t test was used to compare difference in ages between ACC group and MEC group. Nonparametric test was performed to compare difference in tumor′s diameter between ACC group and MEC group. Comparison of genders, history of smoking, tumor-node-metastasis (TNM) stage and CT features between ACC group and MEC group were tested using Fisher′s exact tests. Survival was calculated using the Kaplan-Meier method, and the survival curves were compared by the log-rank test.Results Compared to MEC, patients with ACC were older. There were significant difference between the two groups (t=3.154, P<0.05). ACC tended to involved trachea or main bronchi (13/14) while MEC were mostly located at lobar or segment bronchi (6/10). The shape of ACC tumors were mainly lobulated or presented as circumferential wall thickening (13/14), while MECs were smoothly oval (7/10). On contrast-enhanced CT scans, ACC mainly showed mild or moderate enhancement (9/10), While most of MEC had shown avid enhancement (8/10). CT findings suggestive of airway obstructive disease were seen more with MEC (9/10) than ACC (4/14). There were significant differences of the above CT features between ACC and MEC group (P<0.05). A case of EMC in an 43 years old female presented rounded nodule in tracheal; The SUVmax in 6 of 8 cases of PET/CT exceeded 2.2; Overall survival (OS) was 87.5% in all cases. No significant difference was found between ACC and MEC groups regarding OS (χ^2=0, P=1.000). Ages, surgical and nonsurgical patients and TNM stage were found to be related to OS (χ^2=13.799, 13.799, 13.171, respectively, P<0.05).