CT of adenoid cystic carcinoma of the trachea.

The CT features of six cases of adenoid cystic carcinoma of the trachea are presented and compared to the bronchoscopic, surgical, and pathologic findings. CT accurately demonstrated extratracheal extension of tumor, which occurred in all six cases and which was not visible on standard chest radiographs. This information was helpful in planning the surgical approach. However, CT consistently underestimated the longitudinal extension of the lesion because of partial volume averaging and the tendency of adenoid cystic carcinoma to grow submucosally. CT was also a poor predictor of mediastinal organ invasion. Because recent advances in tracheal resection and carinal reconstruction have made many of these lesions resectable, CT is frequently used in the evaluation of the operability of patients with adenoid cystic carcinoma. However, its usefulness in this regard is limited, and conventional techniques such as standard tomography continue to play a role in preoperative assessment.