Clinical features of extramedullary multiple myeloma

Objective:To investigate the incidence and clinical features of extramedullary multiple myeloma(EM).Method:Three hundred and fifty-seven patients with multiple myeloma(MM) were retrospectively analyzed for the incidence of EM,clinical and laboratory features,therapeutic effects and outcome.Result:Forty-three EM were found at the diagnosis or during therapy,thus the incidence rate was 12.04%.In the logistic regression analysis,only the type of immunoglobulin was associated with EM(P0.05).The most common location of EM was soft tissues.In 35 patients whose therapeutic effect could be evaluated,2 were nCR(5.7%),7 were PR(20.0%),and 9 were MR(25.7%).Therefore the total effective rate was 51.4%.Median time to progression was 7.5 months(1~18 months).The estimate overall survival(OS) of patients with EM was significantly shorter than those without EM(31.0 months vs.42.4 months,P0.05).Twenty-five patients were found to have EM at diagnosis,and their estimate OS was 19.1 months.Eighteen patients were found to have EM during therapy,and their estimate OS was 42.7 months(P0.01).Conclusion:The incidence of EM may be associated with type of immuglobulin.For patients with EM,conventional chemotherapy is with poor efficacy and the prognosis is unfavourable,especially when the diagnosis of EM is concurrent with the diagnosis of MM.