Ruxolitinib-Associated Improvement in Post-transplant Air-Leak Syndrome Complicating Steroid-Dependent Organizing Pneumonia: A Case Report.

Air-leak syndrome (ALS), including pneumothorax, pneumomediastinum, and subcutaneous emphysema, is a rare but life-threatening complication after allogeneic hematopoietic stem cell transplantation (HSCT). However, no standard treatment has yet been established. Here, we report the case of a 60-year-old man with acute myeloid leukemia who underwent allogeneic HSCT. He developed chronic graft-versus-host disease (GVHD) and cryptogenic organizing pneumonia (COP) on day 126 after transplantation. Although initial corticosteroid therapy improved the COP, the relapse occurred during tapering, and repeated steroid treatment failed to achieve sustained disease control. The patient subsequently developed pneumomediastinum, consistent with ALS. Ruxolitinib treatment was initiated on day 265 for steroid-dependent chronic GVHD and organizing pneumonia. Following treatment, oxygenation improved, pneumomediastinum improved, and corticosteroids were successfully tapered and discontinued without COP recurrence. Serum Krebs von den Lungen-6 (KL-6) levels decreased in parallel with clinical and radiological improvement. The introduction of ruxolitinib is associated with improvements in ALS and enabled the discontinuation of steroids. Adverse events included cytopenia and mild liver dysfunction, consistent with known safety profiles. The patient died of acute respiratory failure after transfusion, which was not considered a direct complication of the ruxolitinib treatment. This case suggests that ruxolitinib may facilitate corticosteroid tapering and radiographic improvement of organizing pneumonia-associated ALS after allogeneic transplantation.