Allogeneic HSCT For Pediatric Extranodal NK/T-Cell Lymphoma Transformed From Chronic Active Epstein-Barr Virus Infection: A Case Report.

This study aimed to explore the clinical characteristics, diagnostic criteria, therapeutic regimens, and prognostic features of pediatric extranodal natural killer/T-cell lymphoma (ENKTL) transformed from chronic active Epstein-Barr virus infection (CAEBV), to provide evidence-based references for standardized clinical diagnosis and treatment of these refractory diseases. A pediatric patient with CAEBV-transformed ENKTL admitted to Nanshan Hospital Affiliated to Shenzhen University was retrospectively enrolled in this study, who received allogeneic hematopoietic stem cell transplantation (allo-HSCT). The patient achieved complete remission after multiple cycles of preoperative chemotherapy. Triple probiotic preparations containing Bifidobacterium, Bacillus licheniformis, and Lactobacillus were administered throughout the preconditioning phase and post-transplant period. Persistent complete remission was achieved after transplantation with full donor chimerism of 100%. Long-term follow-up over 1 year post-transplantation showed no disease recurrence, EBV reactivation, severe infectious complications, or acute and chronic transplantation-related complications. This case study confirmed that allo-HSCT is safe and effective for the treatment of pediatric CAEBV-transformed ENKTL, with a significantly superior long-term prognosis compared with chemotherapy alone. Peri-transplant adjuvant application of microecological preparations may reduce the risks of respiratory tract infection and graft-versus-host disease in children. Given that this is a single-case study with limited follow-up duration, there are certain limitations in the clinical generalization of the conclusions.