Histology USMLE Step 1 Practice Question
A 65-year-old man with a 40-pack-year smoking history presents with hemoptysis, progressive dyspnea, and unintentional weight loss over 3 months. Chest X-ray demonstrates a 3-cm hilar mass. Bronchoscopy with endobronchial biopsy is performed. Histologic examination reveals a tumor with small, uniform cells featuring round nuclei, scant cytoplasm, and finely dispersed chromatin described as having a 'salt-and-pepper' appearance. Immunohistochemistry is positive for chromogranin A and synaptophysin. Which of the following best describes the cell of origin for this malignancy?
Answer choices
- AMucus-secreting goblet cells of the bronchial epithelium
- BCiliated columnar epithelial cells of the bronchi
- CNeuroendocrine cells (Kulchitsky cells) of the bronchial epitheliumCorrect answer
- DClub cells (Clara cells) of terminal bronchioles
- EFibroblasts of the bronchial submucosa
- FSquamous epithelial cells lining the alveoli
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