[Pathology of pulmonary changes in Wegener's granulomatosis, rheumatoid arthritis and polyarteritis nodosa (author's transl)].

Histology of the pulmonary alterations which may occur in Wegener's granulomatosis, rheumatoid arthritis and polyarteritis nodosa is enumerated. 30 own cases with pulmonary lesions are presented. The difficulties of differential diagnosis in lung biopsies are discussed. Both Wegener's granulomatosis and rheumatoid arthritis may terminate in a generalized necrotizing arteritis which cannot be distinguished from polyarteritis nodosa. This as well as various other similarities indicate that these three different disease entities base on an identical hyperergic reaction of the vascular wall. Only the so-called limited type of Wegener's granulomatosis has a relatively favourable prognosis.