Durvalumab-Induced Diffuse Alveolar Hemorrhage: An Autopsy Case Report.

Durvalumab, a programmed cell death ligand 1 inhibitor, induces various immune-related adverse events (irAEs), including lung injury. However, diffuse alveolar hemorrhage (DAH) is a rare type of lung injury due to immune checkpoint inhibitors. A 76-year-old man with c-stage IIIA squamous cell carcinoma of the lung received maintenance durvalumab therapy after chemoradiotherapy. He developed dyspnea and malaise after 11 cycles of durvalumab. Chest computed tomography showed rapidly spreading bilateral ground-glass opacity in the lungs. We diagnosed DAH by hemosiderin-laden macrophages in bloody bronchoalveolar lavage fluid. Despite mechanical ventilation, steroids, and cyclophosphamide, he died of respiratory failure. The autopsy revealed that fresh and old bleeding areas coexisted, and neither pulmonary vasculitis nor diffuse alveolar damage was detected microscopically. Furthermore, CD3+ and CD8+ lymphocytes were observed in the lung interstitium, whereas CD20+ and CD4+ lymphocytes were scarcely detected. We report the first case of durvalumab-induced DAH. We should be alert to irAEs with DAH as a potential differential diagnosis of lung injury during durvalumab treatment.