An autopsy lung from a coal miner shows multiple small black pigmented lesions scattered in the upper lobe parenchyma. Microscopically each lesion consists of dust laden macrophages surrounding a dilated respiratory bronchiole with adjacent focal airspace enlargement. This basic lesion of coal workers' pneumoconiosis is termed the:
- A Silicotic nodule with whorled concentric collagen
- B Asbestos body with interstitial fibrosis
- C Coal macule with focal emphysema ✓
- D Ghon focus with central caseation
Correct answer: C. Coal macule with focal emphysema
Explanation
The coal macule, a collection of carbon pigment laden macrophages around a dilated respiratory bronchiole accompanied by focal centrilobular emphysematous change, is the hallmark lesion of simple coal workers' pneumoconiosis, favoring the upper lobes. Silicotic nodules show whorled hyalinized collagen with concentric layering and are distinguished microscopically by birefringent silica. Asbestos exposure produces ferruginous bodies and lower zone interstitial fibrosis, while a Ghon focus is granulomatous caseation of primary tuberculosis.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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