Epstein-Barr virus (EBV)-associated B-cell post-transplantation lymphoproliferative disorder (PTLD) is a severe complication following solid-organ transplantation (SOT) and allogeneic hematopoietic stem cell transplantation (HSCT). We present a case of a 15-year-old male developing a monomorphic B-cell PTLD after receiving an allogenic stem cell transplant for acute acute myeloid leukemia. A diagnostic lymph node biopsy revealed monomorphic type, B cell phenotype, associated with Epstein-Barr virus, consistent with post-transplant lymphoproliferative disorder (PTLD). The morbidity and mortality of PTLD are high, and there is no standard protocol for treatment of PTLD. To prevent the occurrence of PTLD and early intervention are important for the prognosis of patients.