Nodal T/NK-cell lymphoma of nasal type: a clinicopathological study of six cases

Aims:  To investigate the clinicopathological features of six unusual cases of nodal CD56+ and Epstein–Barr virus (EBV)+ T/natural killer (NK)-cell lymphoma, a putative nodal counterpart of nasal NK/T-cell lymphoma (nodal T/NK-cell lymphoma of nasal type) in comparison with nasal NK/T-cell lymphoma with secondary lymph node involvement ( n  = 24) and peripheral T-cell lymphoma (PTCL) of cytotoxic molecule (CTM)+ and EBV+ type ( n  = 21).
Methods and results:  All cases of nodal T/NK-cell lymphoma of nasal type exhibited diffuse infiltration of pleomorphic medium-sized to large tumour cells, reminiscent of those in CTM+ EBV+ PTCL. The tumour cells had a typical phenotype of nasal NK/T-cell lymphoma: CD2+, CD3ε+, CD4?, CD5?, CD56+, T-cell intracellular antigen-1+, granzyme B+, perforin+ and EBV+. However, four of six cases demonstrated clonal T-cell receptor γ-gene rearrangement on polymerase chain reaction analysis, unlike nasal NK/T-cell lymphoma. Comparison of clinical parameters and overall survival among the three groups demonstrated only minor differences.
Conclusions:  Nodal T/NK-cell lymphoma may occupy the grey zone between extranodal nasal-type NK/T-cell lymphoma and nodal CTM+ PTCL in a spectrum of NK to T-cell lymphomas that are EBV+. The close relationship between NK/T-cell lymphomas and cytotoxic T-cell lymphomas was also substantiated.