Legionella pneumonia complicating Wegener's granulomatosis.

We describe a previously healthy man who presented with features consistent with Wegener's granulomatosis. While undergoing investigation, he developed acute respiratory failure, thought to represent progression of his vasculitis. Open lung and sinus biopsies were performed to obtain the diagnosis. Vasculitis was confirmed on the paranasasl biopsy, and the lung biopsy showed pneumonia due to Legionella pneumophila, an association not previously reported in Wegener's granulomatosis. If immunosuppressive therapy had been started without making the diagnosis of Legionella pneumonia on lung biopsy, the patient might well have succumbed to the infection.