Open lung biopsy in the diagnosis of Pneumocystis carinii pneumonia.

Lung biopsy remains the essential cornerstone in the diagnosis of pneumocystis pneumonia. Whatever technique can establish this diagnosis safely and early in order to get treatment started quickly should be used. Open lung biopsy remains a candidate for the diagnostic method of choice because if offers some advantages over percutaneous needle biopsy. There is a greater supply of competent thoracic surgeons in most hospitals than of physicians who are proficient with needle biopsy. The direct vision afforded by thoracotomy enables selective biopsy of grossly involved lung that can be appreciated by direct vision and palpation; needle biopsy is random and blind in its sampling. A more generous tissue specimen can be obtained for pathologic examination; the pathologic diagnosis of an "unsatisfactory specimen" is unlikely to result from open biopsy. Open lung biopsy achieves a higher diagnostic yield earlier in the pneumonitis when pneumocystis pneumonia is confined to the perihilar regions inaccessible to percutaneous needle biopsy. Better control of hemostasis is achieved by direct vision and ligature in a group of patients characteristically at high risk for bleeding tendencies, and pneumothorax is controlled in open biopsy; thoracostomy prevents the later, uncontroled collapse of the lung when the patient returns to the ward where there may be some diagnostic and therapeutic delay in the treatment of pneumothorax in a patient who can tolerate little further respiratory compromise.