We report the case of a 52-year-old man with Wegener's granulomatosis complicated with seropneumothorax. Pneumothorax or seropneumothorax has previously been reported as a rare complication of Wegener's granulomatosis. The patient was successfully treated with prednisolone and cyclophosphamide, and seropneumothorax was resolved without tube drainage. This case suggests that the pathogenesis of seropneumothorax may be associated with the disease activity of Wegener's granulomatosis because it developed spontaneously before treatment with immunosuppressive agents and without being complicated by infection.
