• The incidence of non-primary infiltration-related central nervous system diseases after allogeneic hematopoietic stem cell transplantation was 6.4% (19/298), with a median onset time of 16 days post-transplant.
• Key risk factors included delayed granulocyte and platelet engraftment, prior central nervous system leukemia, and grade III-IV graft-versus-host disease.
• The cumulative mortality in affected patients was 47%, significantly higher than 28.6% in controls, and overall survival at 1 and 2 years was markedly lower.
• Etiologies included calcineurin inhibitor-related encephalopathy, infections, thrombotic microangiopathy, and intracranial hemorrhage, emphasizing the need for early etiological diagnosis and targeted intervention.