[A case of Swyer-James syndrome with interesting chest radiographs].

A 28-year-old man was admitted for further examination after overinflation of the right lung was observed on a screening chest radiograph. The chest radiograph on admission showed increased radiolucency of the left lung and overinflation of the right lung, associated with a shift of the mediastinum toward the midline on expiration. High-resolution CT on expiration showed air trapping in the left lung and in part of the right lower lobe. Pulmonary perfusion scintigraphy showed a markedly decreased perfusion in these areas. Pulmonary angiography revealed small left pulmonary arteries with diminished peripheral vascular branches. Bronchoscopy showed no abnormality of either bronchus. Swyer-James syndrome was diagnosed on the basis of these findings. Although bronchial damage due to the lower respiratory tract infection during childhood is considered a very important factor in the pathogenesis of this syndrome, many patients have no history of airway infection, as in this case. This is a rare case of Swyer-James syndrome presenting with marked overinflation of the unaffected lung in an asymptomatic adult. Progression of this compensative overinflation probably involved asymptomatic damage caused by the weakness of the affected lung.