Autopsy Case of Epstein-Barr Virus-associated T-cell Post-transplant Lymphoproliferative Disorder with Mono- and Polymorphic Lesions: Possibility of 'Polymorphic T-cell Post-transplant Lymphoproliferative Disorder'.

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) is predominantly of B cell origin. The concept of clonal evolution from poly- to monoclonal lymphoproliferation has been put forward, but T-cell PTLDs are rare with an unknown etiology. In a unique autopsy case of a 53-year-old man with EBV-associated T-cell PTLD, we observed polymorphic T-cell proliferation across several organs and monomorphic T-cell proliferation in the perforated ileum. Interestingly, both manifestations exhibited identical monoclonal peaks in the T-cell receptor rearrangement polymerase chain reaction (PCR) analyses. These findings suggest the existence of clonal evolution in EBV-associated T-cell PTLD, leading to the proposal of the novel concept of polymorphic T-cell PTLD.