Peripheral T-cell lymphoma with progression to a clonally related, Epstein Barr virus+, cytotoxic aggressive T-cell lymphoma: evidence for secondary EBV infection of an established malignant T-cell clone.

We report a case of primary Epstein Barr virus (EBV) negative peripheral T-cell lymphoma (PTCL) NOS in a 56-year-old female who-after an initially indolent course – simultaneously developed an aggressive, EBV+ cytotoxic large T-cell lymphoma, clonally related to the primary PTCL, and an EBV+, clonal