原发性肺黏液表皮样癌的CT表现

CT Manifestations of Primary Pulmonary Mucoepidermoid Carcinomas

目的探讨原发性肺黏液表皮样癌(MEC)的CT表现,以提高对该病的诊断水平。方法回顾分析经病理证实的23例肺MEC的CT表现及临床、病理资料。结果病灶位于气管下段3例,主或中间段支气管10例,叶支气管5例、段支气管3例、周围型2例。病灶呈边界清楚的气道腔内型肿物18例,其中10例呈与气道长轴一致、基本或完全阻塞气道的椭圆形肿物,4例呈部分阻塞气道的类圆形肿物、4例呈部分阻塞气道的不规则肿物;病灶呈气道腔内外浸润者3例,其中1例左主支气管病变完全填塞气道并与周围组织分界不清,1例左上叶支气管病变向腔外侵犯形成肺内肿块,1例病灶浸润纵隔间隙并突入气管腔。病灶呈肺内类圆形肿物2例。平扫4例见钙化,增强20例中明显强化16例。18例合并气道阻塞改变。病理证实20例为低级别MEC,3例为高级别MEC。结论 MEC在CT上多表现为中央型气道腔内边界清楚的类圆形或不规则形肿物,强化明显;少部分亦可表现为侵犯气道腔内外的不规则肿物或周围型肺内肿物。

Objective To discuss the CT findings of primary pulmonary mucoepidermoid carcinoma（ MEC） in order to improve its diagnostic accuracy. Methods The CT features,clinical data and histopathological findings of 23 patients with pathologically-proved primary pulmonary mucoepidermoid carcinoma were retrospectively analyzed. Results Of the23 patients,the lesion was located at lower trachea in 3,at the main or intermediate bronchus in 10,at lobar bronchus in5,at segmental bronchus in 3,and at the peripheral lung in 2. On CT scan the lesions presented as a well-bordered mass within the airway（ n = 18）,with its long axis being parallel to the airway running direction（ n = 8）. In 4 cases,the lesion was round in shape and the airway was partially obstructed,and in other 4 cases the lesion was irregular in shape and the airway was also partially obstructed. Infiltration,both in and outside the bronchial lumen,was found in 3 cases,in one of them the left main bronchus was completely obstructed. In one patient with the tumor being at left upper lobe the lesion grew across the bronchial wall to form a mass in the lung. In one case the lesion invaded the mediastinal space and protruded into the trachea. The lesion was manifested as a round pulmonary mass in two cases. On plain CT scan,calcification was seen in 4 cases. Among 20 cases receiving contrast-enhanced CT scanning,obvious enhancement was found in 16.Airway obstruction change was detected in 18 cases. Pathological examination indicated that low-grade and high-grade mucoepidermoid carcinoma could be confirmed in 20 and 3 cases respectively. Conclusion On CT image,the primary pulmonary mucoepidermoid carcinomas usually present as a well-defined round or irregular mass within the central airway with obvious enhancement on contrast-enhanced scan. In a few patients,the lesion is characterized by an irregular mass invading the airway lumen,or by a peripheral lung tumor.