Pediatric diamond-blackfan anemia after hematopoietic stem cell transplantation complicated by bronchiolitis obliterans and air-leak syndrome leading to lung transplantation: a case report with multimodal follow-up

Introduction: Bronchiolitis obliterans syndrome (BOS) is a severe, often fatal pulmonary manifestation of chronic graft-versus-host disease (cGVHD) following allogeneic hematopoietic stem cell transplantation (HSCT). Its progression to air-leak syndrome (ALS) signifies a critical deterioration with exceedingly high mortality. Lung transplantation (LTx) remains a rare salvage option, especially in children, with scarce reports of successful outcomes in those with this complication cascade. Case presentation: /FVC 52%), and high-resolution computed tomography (HRCT) revealed mosaic perfusion and bronchial wall thickening, contributing to the diagnosis of BOS. Despite intensive immunosuppressive therapy, she developed ALS on +360d and type II respiratory failure on +475d. Sequential bilateral LTx was performed on October 28, 2025. Postoperatively, the patient recovered following the management of multidrug-resistant bacterial infections and respiratory complications, with no rejection or recurrence of cGVHD during follow-up. Conclusion: This report presents the youngest documented DBA case of successful LTx for BOS complicated by ALS after allo-HSCT globally. It demonstrates that dynamic multimodal monitoring is crucial for early BOS detection. LTx is a viable therapy for end-stage pulmonary cGVHD in children. This case underscores the need for proactive monitoring in high-risk patients and provides a paradigm for managing this complex complication.