Tumors Tumors Mucoepidermoid carcinoma This low-grade, polypoid tumor of the trachea or bronchus has nests composed of squamous cells and glands. This PAS-D stain shows the scattered glands with red secretion within the squamous nests. They are usually found peripherally. Adenoid cystic carcinoma These are low-grade tracheal or bronchial tumors that resemble bronchial ducts or glands. The nests are composed of epithelial and myoepithelial cells.
Tumors have an infiltrative growth that is difficult to eradicate completely.
The gland-like pattern develops as tumor surrounds stroma, but some true glands do occur.