A 55-year-old farmer with chronic cough and dyspnea undergoes HRCT chest. Imaging shows diffuse, smoothly thickened interlobular septa producing a polygonal pattern, with central, dense hilar lymph nodes containing peripheral ('egg-shell') calcification. Which diagnosis is most likely?
- A Silicosis ✓
- B Lymphangitic carcinomatosis
- C Sarcoidosis
- D Pulmonary alveolar proteinosis
Correct answer: A. Silicosis
Explanation
Silicosis classically produces smoothly thickened interlobular septa (septal thickening) and eggshell calcification of hilar lymph nodes in patients with occupational dust exposure such as farming or mining. Sarcoidosis can cause lymph node calcification but not typically eggshell pattern and usually shows perilymphatic nodules. Lymphangitic carcinomatosis causes nodular septal thickening, not smooth. Pulmonary alveolar proteinosis shows crazy-paving, not eggshell calcification.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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