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Table 4 Criteria used for the classification of lungs based on histologic examination

From: First confirmation by PCR of Jaagsiekte sheep retrovirus in Ireland and prevalence of ovine pulmonary adenocarcinoma in adult sheep at slaughter

Histological lesion category Description
Abscess Thick fibrous capsule (or part thereof) surrounding viable +/− degenerate neutrophils +/− central liquefactive necrosis
Bronchopneumonia Alveolar and bronchial/bronchiolar lumina filled with admixed neutrophils, macrophages and lymphocytes, +/− type 2 pneumocyte hyperplasia, bronchiolitis obliterans, oedema, bacterial colonies, regions of fibrosis
Interstitial thickening Extensive-diffuse, mild-marked thickening of the alveolar septa due to smooth muscle hypertrophy +/− fibroblasts.
Histologically Suspect OPA (HSO) Single-multifocal, well-demarcated-infiltrative tumours with papillary/lepidic/acinar growth patterns consisting of cuboidal-columnar cells supported by a fine fibrous stroma and surrounded by macrophage infiltration.
Parasitic infestation One or more of the following: nematode eggs/larvae, eosinophilic granulomas, eosinophil-rich interstitial and intra-alveolar infiltrates.
Other Pathological changes not falling into any of the other categories described.
Normal No pathological changes