Clinical and pathological features of idiopathic and secondary pleuroparenchymal fibroelastosis in patients undergoing lung transplantation

Introduction: Idiopathic pleuroparenchymal fibroelastosis (IPPFE) has been recognized as a distinct entity. Similar PPFE pattern is also seen in secondary interstitial lung diseases (ILDs), which is categorized as secondary PPFE (SPPFE). IPPFE and SPPFE have not been comparatively studied. Aims and Objectives: To evaluate the clinical and pathological features of IPPFE and SPPFE. Methods: Patients with IPPFE and SPPFE were identified from consecutive recipients undergoing cadaveric lung transplantation (LT) at Kyoto University Hospital between 2010 and 2018. IPPFE was diagnosed through post-transplant multidisciplinary consensus. SPPFE was diagnosed when the diagnostic criteria for IPPFE were fulfilled in secondary ILDs. Clinical data and pathological features of explanted lungs were retrospectively evaluated. Results: Of 104 cadaveric LT recipients, nine were diagnosed as IPPFE and seven as SPPFE. Etiologies for SPPFE were late onset non-infectious pulmonary complication after hematopoietic stem-cell transplantation or chemotherapy in six, and dermatomyositis in one. At the time of LT, the median age of patients was 46 years and eleven were managed with long-time oxygen therapy or mechanical ventilation. Distribution of pathological PPFE was similar between IPPFE and SPPFE. Granulomas and peribronchiolar inflammation were more frequently observed with SPPFE than IPPFE, while the frequency of constrictive bronchiolitis obliterans was not significantly different. Estimated three-year survival rate after LT was 79.6% (IPPFE 75.0%, SPPFE 85.7%). Conclusions: IPPFE and SPPFE have similar PPFE lesions and different additional pathological findings.