Pathology of seven mucous cell adenomas of the bronchial glands with particular reference to ultrastructure

The pathology, including ultrastructure, of seven mucous cell adenomas of the bronchial glands is described. They occurred as polypoid intraluminal lesions in both male and female patients between the ages of 7 and 55 years (mean 26 years). Histologically they were all benign and consisted of predominantly mucus-secreting cells arranged in acini or ducts or in solid groups. A little squamous differentiation was evident in four cases, insufficient in our opinion, to justify the term mucoepidermoid tumour. By electron microscopy, many tumour cells resembled mucous cells of the bronchial glands, containing typical large mucous granules of finely granular, reticular or fibrillated material, and sometimes small electron-dense bodies. In four cases some cells showed both secretory granules and features of squamous differentiation such as numerous tonofilaments and desmosomes. Oncocytic differentiation was seen occasionally.