Primary lymphoma arising in the nasal cavity among Japanese

Aims: Most lymphomas arising in the nasal cavity are thought to be of natural killer (NK) cell origin. However, some reports indicate that T- and B-cell lymphomas may also primarily arise in the nasal cavity. We therefore studied lymphomas arising in the nasal cavity both histologically and immunohistochemically. Methods and results: Of the 32 cases investigated, 20 cases were also available as fresh frozen specimens. We diagnosed 31 cases as extranodal NK/T-cell lymphoma and one as plasmacytoma. The neoplastic cells were immunoreactive for CD3 (polyclonal) 31/31, LMP-1 12/31, CD20 (L26) 0/31, granzyme B 30/31, TIA-1 30/30, CD56 (123C3) 29/31, CD4 0/31 and CD8 3/31. In situ hybridization for Epstein-Barr virus-encoded small RNA-1 (EBER-1) was detected in 31/31. In frozen tissue sections, neoplastic cells mostly showed CD3 (Leu4)-, CD4 (Leu3a)-, CD5 (Leu1)-, CD8 (Leu2)-, CD16 (Leu11)-, CD56 (Leu19)+, beta F1-, TCR delta 1-, perforin+, CD94+ phenotypes. These immunohistochemical findings indicate their NK cell origin. In three cases, neoplastic cells were positive for CD8. In one of these cases, neoplastic cells were positive for CD8 beta and V alpha 24, suggesting their NKT-cell origin. Conclusions: Our present study indicates that primary lymphomas arising in the nasal cavity are mostly of NK cell derivation. Our present study also suggests that a small number of cases are derived from NKT-cells.