Monoclonal gammopathy in extranodal marginal zone lymphoma (ENMZL) correlates with advanced disease and bone marrow involvement

Monoclonal gammopathy is a well-recognized occurrence in splenic marginal zone lymphoma (MZL); however, its prevalence has never been reported in extranodal MZL (ENMZL). We present results of a retrospective analysis of 26 patients with newly diagnosed as well as previously treated ENMZL. Monoclonal gammopathy was detected in 7 out of 26 (27%) patients. All patients with a monoclonal gammopathy had stage IV disease, and most of them had involvement of lymph nodes and/or bone marrow (n = 6). Only 1 out of 7 patients with a monoclonal spike had stage IV disease diagnosed based on multifocal mucosal involvement. There was also a strong correlation between the involvement of bone marrow and the presence of a monoclonal spike (Fisher's exact test, P = 0.0007). Prevalence of monoclonal gammopathy is higher than previously recognized and indicates advanced disease. However, the prognostic significance of the presence of monoclonal gammopathy in this population is unknown. (C) 2004 Wiley-Liss, Inc.