Cytologic diagnosis of adenoid cystic carcinoma in tracheal wash specimens.

Two examples of primary adenoid cystic carcinoma of the trachea are described in which the cytologic diagnosis was made from tracheal washings. It is easy to confuse adenoid cystic carcinoma with the more common small-cell neoplasms of the respiratory tract; however, if differential features are kept in mind, such a distinction can be made in the cytologic material. Differential features include cohesive, globular, honeycomb-like arrangements of cells lacking nuclear molding, three-dimensional cell groups with ball-like formations, and clusters of uniform cells with cystic spaces, some containing mucus. These features in both of our cases resulted in unequivocal cytologic diagnoses.