纵隔胸腺囊肿是一种较少见的胸腺咽管上皮的先天性囊肿。1980年～1989年十年间,在45963例外检中,我们仅遇见2例。现报告如下。例1、男,49岁。胸部x线透视发现纵隔肿块一年,无异常感觉。x线显示:胸腔中纵隔有一密度增高阴影与心影重迭,提示:纵隔占位性病变。手术见:中纵隔囊性肿块,上至胸骨切迹上缘,两侧累及双侧中肺野。病理检查;分叶状囊性肿瘤一个,大小25×20×8cm,切面呈多房性,壁薄如纸,厚处仅0.2cm,囊内含清亮液体,囊壁一处见三个灰红褐色小结,质硬,米粒大。显微镜下:经多处取材,纤维囊壁中仅少处 Mediastinal thymic cysts are a rare congenital cyst of the pharyngeal pharyngeal epithelium. During the decade from 1980 to 1989, in the 45963 exception, we only met 2 cases. The report is as follows. Example 1, male, 49 years old. Chest x-ray findings revealed mediastinal masses for one year without abnormal sensation. X-rays show that there is an increase in density and shadows in the mediastinum in the chest cavity, suggesting a mediastinal space-occupying lesion. Surgical treatment: In the mediastinal cystic mass, up to the upper edge of the sternal notch, bilateral bilateral lung fields involved. Pathological examination; A lobulated cystic tumor, size 25 × 20 × 8cm, multi-room cut surface, thin wall, such as paper, only 0.2cm thick, capsule containing clear liquid, see three red gray wall Brown nodules, hard, large grains of rice. Under the microscope: After multiple sampling, there are only few places in the wall of the fiber capsule