We report a rare case in which Epstein-Barr virus (EBV)-negative polymorphic B-cell post-transplant lymphoproliferative disorder (PTLD) and EBV-negative monomorphic T-cell PTLD [anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL)] were observed simultaneously in the same cervical lymph node, 34 months after liver transplantation for hepatitis C liver cirrhosis. Although hepatitis C recurred after 2 months, he had no other complications until PTLD occurred 34 months post-transplantation. The patient underwent reduction of the immunosuppressive drug and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone therapy, and he was considered to have achieved complete remission. However, PTLD recurred, and he died 6 months after the initial diagnosis. Autopsy revealed only EBV-negative monomorphic T-cell PTLD (ALK-negative ALCL) that involved the liver, spleen, bilateral kidneys, stomach, bladder, heart, bone marrow, right ureter, and pons. Thus, recurrent PTLD may show a different histological type from the primary disorder, as PTLD has a multiclonal potentiality that causes various types of lymphomas. Therefore, it may be difficult to predict PTLD-related prognosis from the initial PTLD histological identification.