Evaluation of transbronchial biopsy of the lung.

Transbronchial biopsy of the lung through the fiberoptic bronchoscope is becoming a widely utilized clinical diagnostic technic. The authors reviewed the histologic features of 109 consecutive cases. The primary problem is the small size of the pulmonary tissue samples obtained, which is further compounded by an apparent mechanical inability to enter the biopsy forceps into dense nodules of neoplastic tissue. The diagnosis of carcinoma can best be made by examining the periphery of the cancer for microscopic extension into adjacent pulmonary parenchyma; however, multiple levels of the tissue block are needed to find such foci. A second problem reflects the use of transbronchial biopsy in the early clinical evolution of various infectious diseases in which pulmonary tissue may contain organisms without a fully developed inflammatory response, which would ordinarily provide the clue to the infective agent. The latter problem appears in cases of infections by Pneumocystis carinii. Close cooperation between the clinician and the pathologist is particularly important in all of these clinical situations.