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?
- A)Neoplasia due to irreversible oncogenic mutation
- B)Hyperplasia caused by increased mitotic activity of mature ciliated cells
- C)Dysplasia with invasion through the basement membrane
- D)Apoptosis caused by caspase mediated cell death
- E)Metaplasia caused by reprogramming of local stem cellsGABARITO
Explicação
Squamous metaplasia in smokers is an adaptive substitution of one mature cell type for another better able to withstand chronic irritation. It occurs through reprogramming of local tissue stem cells or undifferentiated mesenchymal cells, not direct conversion ... Ver explicação completa e trilha adaptativa →