[Refractory multiple myeloma preceded by extramedullary plasmacytoma of lymph node--a case report and review of the literature].

It has been reported that extramedullary plasmacytoma (EMP) tends to be characterized by an indolent clinical course and lower incidence of progression to multiple myeloma. Primary plasmacytoma of lymph nodes is extremely rare and details of its clinical picture remain unclarified. We recently encountered an unusual case of EMP of lymph nodes that progressed to refractory multiple myeloma only 18 months later. A 74-year-old woman was admitted to our hospital because of a painless swelling in the right inguinal region. A tumor was removed surgically, and a histological diagnosis of EMP of the lymph nodes was made. Bence Jones protein (BJP) was detected in the urine, but there was no other evidence of systemic myelomatosis. The patient received local irradiation, which resulted in the elimination of BJP. Eighteen months later, however, a tumor developed in her right stemo-clavicular joint. A bone survey revealed multiple osteolytic lesions, and many atypical plasma cells were observed in the bone marrow, indicating multiple myeloma. The patient deteriorated despite several regimens of combination chemotherapy, and died four and a half years after the initial diagnosis of EMP.