Hepatosplenic γδ T‐cell lymphoma: relation to Epstein–Barr virus and activated cytotoxic molecules

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Abstract
Aims: Hepatosplenic γδ T‐cell lymphoma (TCL) is a rare, aggressive subset of peripheral TCL that presents with hepatosplenomegaly and cytopenia. Epstein–Barr virus (EBV) infection and activated cytotoxic molecules (granzyme and perforin) are uncommon in hepatosplenic γδ CTL. EBV infection and activated cytotoxic molecules are occasionally detected in non‐hepatosplenic γδ TCL. We describe the clinicopathological features of three Japanese cases who were not immunodeficient.Methods and results: All cases showed γδ T‐cell type (CD2+, CD3+, T‐cell receptor (TCR)δ‐1+, βF1−). Two cases expressed natural killer (NK) cell‐associated antigens (CD8–, CD16+, CD56+; CD8−, CD16−, CD56+), and one expressed CD8 (CD8+, CD16−, CD56−). All cases expressed cytotoxicity‐associated molecules (perforin, granzyme B, TIA‐1 and Fas ligand). However, perforin and Fas ligand were not detected in one case. In‐situ hybridization analysis with EBER probes revealed strong nuclear positivity in all neoplastic cells. In addition, two cases showed clonal bands of the EBV terminal repeat (TR) gene. Cytologically, instead of the presence of monomorphic medium‐sized cells, our three cases showed pleomorphic medium‐sized and large cells.Conclusions: Our γδ TCL cases were clinicopathologically considered to be compatible with hepatosplenic γδ T‐cell lymphoma. However, with regard to EBV association, activated cytotoxic profile and cytological features they resembled non‐hepatosplenic γδ TCL. EBV may play a role in this disease by inducing cellular activation.