[Diffuse infiltrative lung diseases of infectious and neoplastic origin].

Among the causes of chronic diffuse infiltrative lung diseases, infection and neoplasia have to be suspected in priority because of their frequency and their therapeutic specificities. Diffuse infiltrative lung diseases related to infection, often acute and feverish, are due to Pneumocystis carinii pneumonia, miliary tuberculosis, or virus and atypical pneumonia. Strategy for microbiological diagnosis depends on the pathogen suspected and the pulmonary disease severity. By contrast, diffuse infiltrative lung diseases due to neoplasia, mostly chronic diseases, include lymphangitic carcinomatosis and more rarely diffuse bronchoalveolar carcinoma and lymphoproliferative diseases.