A comatose 35-year-old man is admitted to the hospital after being involved in a motorcycle collision. He is intubated and mechanically ventilated. He dies 8 weeks later. A photomicrograph of tracheal tissue obtained at autopsy is shown. Which of the following processes best describes these findings?
Correct answer : E. Metaplasia
Normal trachea has ciliated pseudostratified columnar epithelium. But prolonged irritation (in this case due to the endotracheal tube) can induce metaplasia resulting in formation of stratified squamous epithelium (seen in the histology specimen).