Optimization of Lung Explant Sampling to Achieve Accurate Diagnosis

Purpose Explanted lungs are histopathologically reviewed to confirm or establish the diagnosis of the underlying lung disease and to identify other potentially important findings such as acute lung injury or malignancy. Currently there are no guidelines to direct explant sampling. We aimed to identify optimal lung explant specimen sampling and to better understand how additional pathologic findings may impact outcome of patients. Methods All explants (1/2009-1/2019) were initially sampled (“routine sampling”) aiming for in general one section per lobe taken at the interface between fibrosis and preserved lung parenchyma in fibrosing ILD and any abnormal areas. Four additional sections per lobe were obtained based on a “standardized protocol”. All cases were reviewed by a thoracic pathologist. Results One hundred sets of explanted lungs (retrospective [N=93], prospective [N=7]) were sampled including 51 with fibrotic and 49 with non-fibrotic lung disease (table 1). To date we have reviewed 46 of these cases and identified additional pathologic findings in 12 (26.1%) (table 1). In 3 (6.5%) cases additional pathologic features were identified to better classify cases as possible chronic hypersensitivity pneumonitis (N=2) or pleuroparenchymal fibroelastosis. In 36 (78%) reviewed cases these additional findings were identified when 3 sections per lobe were examined. Conclusion Our preliminary results suggest that additional sampling from each lobe of lung explants may help to better define the main pathologic process and capture additional findings in a subset of cases. Additional cases will be reviewed and correlation of morphologic findings with post-transplantation outcome of patients will be performed.