Pathology of diffuse lung disease

The most important aspect of the pathologic evaluation of diffuse lung disease is correlation of the findings with the clinical and radiologic features. This is emphasized throughout the chapter and numerous examples are given. Clinical and radiologic correlation, particularly with HRCT, improves the overall clinical diagnostic accuracy, as well as helping to hone pathologic interpretation and differential diagnosis. Such correlation is important in all lung biopsy samples, including surgical lung biopsies and even transbronchial biopsies. While in general a surgical lung biopsy is more likely to give a diagnosis, there are a number of situations where transbronchial biopsies are useful and these are outlined. This chapter includes general comments on the finding of fibrosis, interstitial inflammation, acute lung injury, and granulomatous inflammation. The following entities are discussed: sarcoidosis, idiopathic pulmonary fibrosis/usual interstitial pneumonia, nonspecific interstitial pneumonia, interstitial lung disease associated with the collagen vascular diseases, vasculitic syndromes, alveolar hemorrhage syndromes, hypersensitivity pneumonitis, pulmonary alveolar proteinosis, lymphangioleiomyomatosis, bronchiolitis, pneumoconiosis, and drug reactions.