Clinicopathological findings of systemic Epstein-Barr virus-positive T-lymphoproliferative diseases in younger and older adults.

Background: Systemic Epstein-Barr virus T-cell lymphoma (sEBV TCL) occurs in childhood and young adults, and is exceptionally rare in older adults.

Methods: We investigated clinicopathological features in 16 patients of various ages with systemic EBV CD8 T-lymphoproliferative diseases.

Results: Eight younger patients and four of eight older adults had sEBV CD8 TCL, with invasion by medium-sized to/or large atypical lymphocytes primarily in bone marrow and lymph nodes, hemophagocytic lymphohistiocytosis (HLH), and progressive clinicopathological course. A further two patients demonstrated EBV node-based CD8 large TCL without HLH, while the remaining two had the systemic form of chronic active EBV infection (sCAEBV) with CD8 small lymphocytes. Past history of sCAEBV-like lesions was observed in one sEBV TCL patient (8.3%). Immunohistologically, in 12 sEBV TCL patients, atypical lymphocytes were positive for phosphate signal transducer and activator of transcription 3 (66.7%), CMYC (83.3%), and p53 (75%). Strong reactions of programmed cell death-ligand (PD-L)1 tumor or non-neoplastic cells were detected in nine sEBV TCL patients (75%). Clonal peaks of the T-cell receptor (TCR) γ gene were detected in eight sEBV TCL patients by polymerase chain reaction. Four younger patients in sEBV TCL (33.3%) are in remission with chemotherapies including etoposide, and three of the four underwent allogeneic stem cell transplantation (SCT).

Conclusion: sEBV CD8 TCL was observed in younger and older adults with less history of sCAEBV. HLH, tumor cell atypia, immunohistological findings, and progressive clinical course were characteristic of sEBV CD8 TCL. Prompt chemotherapy and SCT induced tumor regression in sEBV CD8 TCL patients.