Objective  This study is to improves the understanding of adenoid cystic carcinoma (ACC) of the tracheobronchial tree by observing the multi-slice cornputed tomography (MSCT) features.

  Methods  The MSCT features of 19 cases with primary tracheobronchial ACC confirmed by histopathology were retrospectively analyzed.

  Results  Among the 19 cases, lesions were located in the trachea in seven cases, in the segmental and above segmental bronchi in 10 cases, in the peripheral lung in two cases. Intra- and extraluminal growth were observed in 15 cases (79%), whereas broad-based intraluminal lesions were exhibited in two cases (11%). Among the seven cases of tracheal ACC, the CT scans for five cases showed a notable tendency toward submucosal extension. Two cases manifested as a diffuse or circumferential wall thickening of the trachea, and the other three cases presented homogeneous mass filling of the trachea with wall thickening. The 10 cases with bronchial ACC were manifested as intra- and extraluminal growth. Eight cases presented homogeneous polypoid growth toward the adjacent lumen, and seven cases presented extraluminal parts that were larger than the intraluminal parts. Among 13 contrast-enhanced examinations, three cases were without enhancement, five cases were slightly enhanced, four cases were moderately enhanced, and one case was highly enhanced.

  Conclusion  MSCT performances of ACC of the tracheo-bronchial tree possessed certain characteristics, such as broad-based mass, intra- and extraluminal growth, and diffuse wall thickening. CT can diagnose tumor malignancy, but the definitive diagnosis for ACC should depend on pathology.