Microbiology, X-ray study, and bronchoscopy, including the examination of bronchoalveolar lavage and histology of thransbronchial lung biopsy specimens have proven to be of the greatest informative value in the differential diagnosis of different forms of systemic vasculitis and tuberculosis in 52 patients. Focal pulmonary tuberculosis was detected in the phase of S(II) infiltration on the right in a patient with rheumatic arthritis; Mycobacterium tuberculosis was bacterioscopically detected. The patient underwent specific antituberculous therapy that provided beneficial effects.