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?
- A)Mucus-secreting goblet cells of the bronchial epithelium
- B)Ciliated columnar epithelial cells of the bronchi
- C)Neuroendocrine cells (Kulchitsky cells) of the bronchial epitheliumGABARITO
- D)Club cells (Clara cells) of terminal bronchioles
- E)Fibroblasts of the bronchial submucosa
Explicação
Small cell lung cancer (SCLC) arises from neuroendocrine cells (Kulchitsky cells) located in the bronchial epithelium. These cells characteristically contain dense-core neurosecretory granules and express neuroendocrine markers (chromogranin A, synaptophysin, ... Ver explicação completa e trilha adaptativa →