Pulmonary vasculitis occurs most commonly in the collagen vascular diseases and in granulomatous pulmonary disease. In the collagen vascular group, vasculitis causes diffuse interstitial inflammation and subsequent fibrosis, resulting in interstitial radiographic patterns, especially in the lower lung fields. Vasculitis accompanied by granulomatosis typically produces focal inflammation and is, therefore, manifested as nodules and masses. The more typical collagen vascular diseases include rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and dermatomyositis. The most common vasculitis granulomatosis is Wegener's, with similar radiographic abnormalities occurring in lymphomatoid granulomatosis. Atypical examples of vasculitis pulmonary disease include ankylosing spondylitis, in which upper-lung field fibrobullous changes are seen. Periarteritis nodosa and Behcet's syndrome include abnormalities of large vessels and thromboembolic phenomena. Bronchocentric granulomatosis and allergic granulomatosis involve airway abnormalities as well as vasculitis and granuloma formation.