Which of the following conditions involving his lung is most likely to be responsible for this finding?
At autopsy, a 60-year-old man is found to have a peripheral 7 cm area of golden-yellow consolidation on sectioning of the left lung. Microscopically, this area has alveoli filled with foamy macrophages.
A. Mycoplasma pneumonia infection B. Cystic fibrosis C. Adenocarcinoma D. Silicosis E. Squamous cell carcinoma F. Malignant mesothelioma G. Thromboembolism
Squamous cell carcinoma -(e) correct. most squamous cell carcinomas are located centrally and arise in bronchi, leading to obstruction of a large airway that can cause a lipid pneumonia. in this case, the breakdown of lung tissue distal to the mass yields an endogenous lipid pneumonia.(a) incorrect. mycoplasma infection produces an atypical pneumonia with interstitial infiltrates. obstruction of airways is unlikely.(f) incorrect. mesotheliomas arise in the pleura and are peripheral masses unlikely to obstruct proximal bronchi to produce a lipid pneumonia.(c) incorrect. most adenocarcinomas are peripheral and do not arise within a large bronchus.(g) incorrect. thromboemboli obstruct the pulmonary arterial system, not the bronchi.(d) incorrect. the silicotic nodules are small (a few millimeters) and do not obstruct bronchi.