Pathological changes and diagnostic difficulties of hypersensitivity pneumonia / 中国实用内科杂志

Hypersensitivity pneumonia(HP) is one of the rare interstitial lung diseases. The diagnosis, especially the diagnosis of chronic hypersensitivity pneumonia(CHP), has great challenges in clinical, imaging and pathological aspects. In the history of the disease, CHP presents diversity and complexity, and about half of the patients lack diagnostic granuloma, and fibrosis types exist in many forms, such as usual interstitial pneumonia-like fibrosis, nonspecific interstitial pneumonia-like fibrosis, bridging fibrosis or peribronchiolar fibrosis. So HP needs to be differentiated from multiple diseases. In this study, the pathological changes and diagnostic difficulties of HP are summarized and reviewed.