Carcinomas resembling those occurring in salivary glands, such as adenoid cystic carcinoma and mucoepidermoid carcinoma, arise from submucosal glands of the trachea and bronchi. They grow as polypoid masses, undermining intact overlying respiratory epithelium. They are most often diagnosed by bronchial brushing or transbronchial fine needle aspiration.
Cytologic preparations of adenoid cystic carcinoma show cylinders or spheres of small epithelial cells with bland appearance surrounding amorphous basal lamina material. Mucoepidermoid carcinomas are characterized by the presence of squamous, mucinous and intermediate cells, which can be found in cytologic preparations. High grade tumors show marked nuclear atypia.