A 62-year-old retired insulation worker has 20 years of progressive dyspnea with bibasal crackles. HRCT shows lower zone subpleural reticular abnormalities and patchy fibrosis. Lung biopsy demonstrates peribronchiolar and interstitial fibrosis containing beaded golden brown rods with bulbous ends that stain positive for iron. These structures represent:

• A Silica particles coated with calcium salts
• B Beryllium oxide crystals within giant cells
• C Coal dust macules engulfed by macrophages
• D Asbestos fibers coated with iron-containing material ✓

Explanation

Asbestos bodies, also called ferruginous bodies, are asbestos fibers coated with iron-containing proteinaeous material after phagocytosis by macrophages, appearing as golden brown beaded rods with dumbbell or bulbous ends and staining positively with Prussian blue iron stain. Their presence in a background of interstitial fibrosis confirms asbestosis. Coal dust forms non-fibrous anthracotic macules, and berylliosis produces non-caseating granulomas resembling sarcoidosis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.