Primary carcinoma of the trachea.

Two cases of primary carcinoma of the trachea are described. Both patients were female and had smoked cigarettes for many years. One of the tumours was a squamous cell carcinoma and the other an oat cell carcinoma, the commonest and the rarest forms of tracheal cancer respectively. The diagnosis in the case of oat cell carcinoma was confirmed by electron-microscopic demonstration of neurosecretory granules, a unique observation at this site. Oat cell carcinoma of the trachea does not appear to have been recorded previously in a female.