Neoplasia USMLE Step 1 Practice Question
A 72-year-old man with a 50-pack-year smoking history presents with hemoptysis and cough. Vital signs are stable with SpO2 92% on room air. CT chest shows a 6 cm mass in the left upper lobe with hilar lymphadenopathy, rib erosion, and mediastinal involvement. Bronchoscopic biopsy demonstrates squamous cell carcinoma with keratinization and prominent keratin pearl formation. Which of the following best explains the tumor's histologic subtype and aggressive local invasion pattern?
Answer choices
- APeripheral subpleural location with direct invasion of visceral pleura and chest wall through mechanical erosion
- BCentral endobronchial location arising from squamous metaplasia of normal bronchial epithelium with propensity for local infiltrationCorrect answer
- CBronchiolar location with mucinous differentiation leading to obstruction and post-obstructive pneumonia
- DNeuroendocrine origin from Kulchitsky cells with rapid growth and early vascular invasion
- EPeripheral location with adenocarcinoma components that undergo sarcomatoid transformation
- FSmall cell carcinoma arising from neuroendocrine precursor cells with paraneoplastic hormone production
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