[Pathology of rheumatoid lung]

In the framework of rheumatic illnesses, the lungs and pleura are often observed to be involved. Dependent on the basic illness in question, conditions of the bronchoalveolar system, vessels, lymphatic system, and pleura that have developed differently inter- and intra-individually can be diagnosed in topo-regionally variable forms and combinations. In the causal pathogenesis, the initial (auto-) immunological alteration of the alveolar septa plays a role. When the monocytes, macrophages, and fibroblasts are activated, as a result of a chronic inflammatory process there is increasing reparative proliferation, which finally leads to the non-specific end stage of irreversible interstitial fibrosis. The incidence and manifestation forms of lung changes show certain differences dependent on the underlying illness (e.g., rheumatoid arthritis, systemic lupus erythematosus, progressive systemic scleroderma, dermatomyositis and polymyositis, Sjögren syndrome, and mixed connective tissue disease). In addition to vasculitis and granulomatosis of the lung, therapy-induced lung changes must also be considered in the differential diagnosis since almost all basic therapeutic agents can cause this type of lung condition. Good knowledge of the parameters from the viewpoint of possible therapeutic measures is indispensable, as is close cooperation between the treating physician and the pathologist.