NASOPHARYNGEAL LYMPHOMAS - FURTHER EVIDENCE FOR A NATURAL-KILLER-CELLORIGIN

The authors report four cases of sinonasal lymphomas with immunophenot ypic (four cases) and genotypic (three cases) studies. These lymphomas are frequent in Oriental countries, but unusual in Western population s, particularly in France. Although they have been originally consider ed as T-cell lymphomas, their origin remains unclear, and several auth ors have recently suggested that they are a natural killer (NK)-cell p roliferation. The tumor cells of the four cases reported here showed c haracteristics of NK cells. On cryostat sections, they were CD3 negati ve, but CD2 and CD56 positive. The cytoplasm of the tumor cells exhibi ted azurophilic granulations. Using polymerase chain reaction (PCR), n o clonal rearrangement of the T-cell receptor gamma gene was present. Furthermore, clinically, two presented a pharyngeal involvement, and t wo were also characterized by hepatosplenic involvement at the time of the diagnosis. Thus, the present cases provide additional evidence to ward the NK-cell origin of these rare lymphomas. Many sinonasal lympho mas, including the present cases, are positive for Epstein-Barr virus (EBV) (LMP-1 antibody and EBER-messenger RNA probes). This may suggest an important role of EBV as a local factor in their pathogenesis. Cop yright (C) 1996 by W.B. Saunders Company.