Q119: Brown induration of lung is associated with a pathological condition... - Haemodynamic Derangements, Degeneration and Necrosis - Veterinary Pathology- ICAR JRF/SRF 2024 | Agrigyan

• Pathology of Brown Induration of the Lung: Brown induration is the pathognomonic macroscopic and microscopic appearance of the lungs during chronic passive pulmonary congestion, commonly secondary to left-sided heart failure (e.g., mitral valve insufficiency or cardiomyopathy).
• Mechanism & Hemosiderosis: Elevated pulmonary venous pressure forces erythrocytes to extravasate into alveolar spaces. Alveolar macrophages engulf the extravasated RBCs and digest hemoglobin into insoluble golden-brown hemosiderin pigments (hemosiderosis / 'heart failure cells'). Concurrent chronic hypoxia stimulates interstitial fibroblastic proliferation, making the lungs firm, heavy, and russet-brown (brown induration).

Correct option: (4) Haemosiderosis