General Pathology USMLE Step 1 Practice Question
A 54-year-old man with a 35 pack-year smoking history presents with chronic productive cough for 8 months. Vital signs: BP 138/82 mmHg, HR 88/min, RR 18/min, SpO2 98% on room air. Chest X-ray shows no acute infiltrates. Bronchial biopsy demonstrates replacement of normal pseudostratified ciliated columnar epithelium by stratified squamous epithelium. He denies hemoptysis. Which of the following best describes this histopathologic change?
Answer choices
- ANeoplasia due to irreversible oncogenic mutation
- BHyperplasia caused by increased mitotic activity of mature ciliated cells
- CDysplasia with invasion through the basement membrane
- DApoptosis caused by caspase mediated cell death
- EMetaplasia caused by reprogramming of local stem cellsCorrect answer
- FDirect transdifferentiation of mature ciliated columnar cells into squamous cells
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