Primary lymph node plasmacytomas (plasmacytic lymphomas)

To determine whether primary lymph node plasmacytoma (PLNP) is a distinct e ntity among other types of plasma cell neoplasia, we analyzed a large serie s of PLNPs from 2 large lymphoma registries to compare histologic, immunoph enotypic, and clinical features of PLNPs, nonnodal extramedullary plasmacyt omas, and multiple myeloma. Twenty-five PLNPs (clinical data on 15 cases) w ere compared with 10 non-lymph node plasmacytomas and 51 cases of multiple myeloma; 36 cases of reactive plasmacytoses were used as controls. The hist ologic features of PLNP and other extramedullary plasmacytomas were similar The histologic features of PLNPs were more immature than those of reactive plasmacytoses and less immature than in multiple myeloma. The immunophenot ype of PLNPs significantly differed from that of reactive plasmacytoses, ot her extramedullary plasmacytomas, and multiple myeloma. PLNPs did not progr ess to multiple myeloma, unlike other extramedullary plasmacytomas, even th ough survival in PLNPs and other extramedullary plasmacytomas was similar O ur findings suggest that PLNPs may be distinct from other plasma cell dyscr asias.