Gastrointestinal-localized polymorphic post-transplant lymphoproliferative disorder following kidney transplantation after allogeneic hematopoietic stem cell transplantation: a rare case report.

Post-transplant lymphoproliferative disorder (PTLD) is an uncommon but potentially life-threatening complication of solid organ transplantation (SOT) or hematopoietic stem cell transplantation (HSCT). Therefore, early diagnosis and appropriate treatment are crucial. We report a case of a 37-year-old male who developed gastrointestinal-localized Epstein-Barr Virus (EBV)-associated polymorphic PTLD 5 months after kidney transplantation for diabetic nephropathy. The patient had undergone allogeneic HSCT (allo-HSCT) for acute myeloid leukemia 14 years prior and developed chronic graft-versus-host disease and secondary hypogammaglobulinemia. A reduction in immunosuppressive therapy was insufficient to control the PTLD, and the patient achieved complete remission with rituximab monotherapy. To the best of our knowledge, a case of early onset PTLD following SOT after allo-HSCT has not been previously reported. This case highlights that PTLD can develop in patients with prolonged or compounded immunosuppression and emphasizes the importance of PTLD recognition and appropriate diagnosis and management.