Refractory Myeloma Developed with Multiple Extramedullary Tumors and Myelofibrosis

Abstract

Toshie Ogasawara, Shoko Marshall, Hiroshi Kazama, Kiyotaka Kawauchi and Tetsuya Ogawa

The use of novel drugs has improved prognosis in multiple myeloma (MM). However, as the pathophysiology of primary Extramedullary Myeloma (EM) is not well defined due to its rarity, effective treatment for EM is not yet established. We report the case of a 63-year-old man with MM who presented with back pain and fever following the development of extramedullary disease, including subcutaneous tumors accompanied by marrow fibrosis. CT at presentation revealed subcutaneous tumors, mediastinal lymphadenopathy, and pleural involvement with pleural effusion. Peripheral blood exhibited leukoerythroblastosis. Bone marrow biopsy showed diffuse fibrosis and infiltration of large or small atypical cells with high N/C ratio that did not resemble plasma cells, and were positive for CD138 and cytoplasmic IgG/κ immunoglobulin. Biopsy of subcutaneous tumors showed an infiltration of small atypical cells similar to those of bone marrow. The diagnosis was MM with primary EM that was refractory to chemotherapy with bortezomib and progressed with multiple subcutaneous tumors. Intriguingly, molecules related to proliferation including p53, cyclin D1, and Ki-67 were differentially expressed between bone marrow tumor cells and soft tissue tumor cells. In addition, the simultaneous occurrence of primary EM and diffuse myelofibrosis at diagnosis is peculiar.

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