Epstein-Barr virus-associated extranodal NK/T-cell lymphoma, nasal type of the hypopharynx, in a renal allograft recipient: case report and review of literature.

Posttransplant lymphoproliferative disorders (PTLPDs) are predominantly B-cell lymphoproliferations, whereas a T-cell origin is rarely observed. In contrast to B-cell PTLPD, T-cell PTLPDs show an inconsistent association with Epstein-Barr virus (EBV). Until now, only 13 cases of EBV-associated T-cell PTLPDs have been reported. We describe a case of an EBV-associated T-cell PTLPD in a renal allograft recipient 2 years after transplantation. Histologic examination showed medium- to large-sized lymphoid cells with an angiocentric growth pattern and necrosis. The atypical cells showed a CD2+, CD3epsilon+, CD7+, CD43+, CD45R0+, CD56+, and CD4-, CD5-, CD8- betaF1- phenotype with expression of the latent membrane protein (LMP)-1 of EBV. In addition, EBV-specific RNAs (EBER 1/2) were identified by in situ hybridization. Molecular analysis of the T-cell receptor (TCR) gamma chain by polymerase chain reaction (PCR) showed a polyclonal pattern. The morphologic, immunohistochemical, and molecular findings were consistent with a diagnosis of an EBV-associated extranodal natural killer (NK)/T-cell non-Hodgkin lymphoma (NHL) of nasal type. To our knowledge, this is the first reported case of this rare entity in the posttransplant setting.