Animal: Sheep
Organ: Lung
History: Lung samples form Slaughterhouse
Etiology: Ovine respiratory complex
Morphologic diagnosis: Chronic severe inflammation in the bronchiolar wall resulting in the formation of a nodular mass of granulation tissue firmly attached to the airway wall, protruding into the bronchiolar lumen and lined by bronchial epithelium.
Short summary: In severe acute injury, such as highly pathogenic microorganisms, exudate attaches and cannot be removed from the basement membrane of bronchioles and becomes infiltrated by fibroblasts, which form small nodular masses of fibrovascular tissue that develop into well-organized, microscopic polyps inside the bronchiolar lumen, that are covered by bronchiolar epithelium. This lesion is referred to as bronchiolitis obliterans.
Necropsy performed and picture prepared by: Librado Carrasco, Department of Anatomy and Comparative Pathology and Toxicology, Pathology and Immunology Group (UCO-PIG), Córdoba, Spain