Transbronchial lung biopsy: the pathologist's point of view

Background and AimsThe efficacy of flexible cryoprobe in providing high-quality tissue specimens through bronchoscopy for making a diagnosis remains debatable. In this study, we have compared the diagnostic yield of cryoprobe with conventional sampling by forceps. MethodsForty-one patients scheduled to undergo transbronchial lung biopsy (TBLB) in a pulmonary hospital in Tehran, Iran. Each patient underwent conventional TBLB and flexible cryoprobe TBLB (FCLB) sequentially. Specimen adequacy was defined by the presence of at least 50 alveolar spaces or a positive diagnostic yield. Adequacy of specimens, number and percentage of alveolar spaces without artifact, type of artifact, presence of bronchiolar structures and the diagnosis made based on the results of the two methods separately were compared. ResultsThe mean values of tissue section area obtained by forceps and cryoprobe were 6mm(2) [standard deviation (SD)6.7] and 22mm(2) (SD +/- 19.1), respectively (P<0.001). Specimens were adequate in 26 cases of conventional TBLB and 40 cases of FCLB (P<0.001). Of adequate specimens, 14 samples obtained by TBLB and 28 samples obtained via FCLB were diagnostic. A significant difference was also detected between diagnostic and non-diagnostic specimens (P=0.04). Frequency of specimens with >75% artifact-free lung parenchyma was significantly higher in FCLB method. ConclusionFCLB method provides larger tissue samples with better quality compared with TBLB. Higher-quality specimens are associated with less artifact and higher diagnostic yield. Multisite randomized trials are required to improve our knowledge about the benefits and indications of TBLB with cryoprobe.