New perspectives on interstitial lung disease

It is now generally accepted that an end-stage (honeycomb) lung is a distinct disease representing the final product whenever destruction of the alveolar wall is followed by fibrosis and cicatrization instead of cell repair of the alveolar lining. The resulting picture is as distinctive roentgenographically as it is histologically. Some of the causes of end-stage lung disease also represent well-accepted entities with predictable clinical and pathologic findings and, in some cases, distinctive roentgenographic findings as well. Such established entities include asbestosis, inhalation of noxious gas, drug-induced fibrosis as exemplified by bleomycin, rheumatoid lung, scleroderma, and CEP. The other interstitial diseases, largely idiopathic, remain controversial, as exemplified by the question of whether DIP is an independent disease or an early, reversible form of UIP. Clearly, not all patients with idiopathic, non-specific interstitial disease are in significant danger of progressing to end-stage lung disease, and further investigation may lead to an increased ability to predict prognosis from the clinical roentgenographic, and histologic analysis of early interstitial disease.