Cryptogenic fibrosing alveolitis/idiopathic pulmonary fibrosis

Cryptogenic fibrosing alveolitis (CFA), synonymous with idiopathic pulmonary fibrosis (IPF), remains a life-threatening disease: 50% of patients die within 5 yrs. Historically, many diseases that are now considered to be quite distinct have been "labelled" as CFA. More recently, high-resolution computed tomography and new appreciation of the histopathological patterns of idiopathic interstitial pneumonias have enabled disease variants to be defined according to their different responses to therapy and survival. CFA is believed to be induced by an external agent, although it is not clear whether CFA represents the final common outcome of numerous pathogenetic mechanisms or has a single cause. In addition, there are currently no prospective double-blind, placebo-controlled trials of treatment showing superiority of one drug regimen over another. This review attempts to dissect the different patterns of cryptogenic fibrosing alveolitis, illustrate the major features of each, and refine the clinico-radiological-pathological descriptors that together define cryptogenic fibrosing alveolitis as it is understood today.