Pleuroparenchymal fibroelastosis after allogenic hematopoietic stem cell transplantation: important histological component of late-onset noninfectious pulmonary complication accompanied with recurrent pneumothorax

Late-onset noninfectious pulmonary complication after allogenic hematopoietic stem cell transplantation is an important contributing factor associated with high rate morbidity and mortality. We report a case with pleuroparenchymal fibroelastosis (PPFE) occurred after allogenic bone marrow transplantation. The onset was infiltrative shadows in upper lobes, and the haziness spread gradually throughout the lungs with recurrent episodes of pneumothorax in both lungs. Progressive respiratory failure in course of adrenocortical steroid administration eventually caused death. Histological examination in general autopsy showed patchy subpleural fibrosis predominantly distributed in the upper lobes with substantial density rise of elastic fibers in the subpleural area, consistent with the diagnosis of PPFE. PPFE after allogenic transplantation has been seldom reported to date, but it is one of the most important histological components of late-onset noninfectious pulmonary complication after allogenic transplantation characterized by recurrent pneumothorax. Retrospective analysis in our case indicates early diagnosis may be possible by histological evaluation of elastic fibers in lung specimen when pneumothorax is treated surgically. This case suspects that it is important for hematologist and pathologist to aware this progressive disease along with information of histological characteristics, therefore, leading to the establishment of therapeutic strategies and the improvement of poor prognosis.