IgM-λ multiple myeloma presenting with systemic amyloidosis

Abstract

A 59-year-old man was referred to our hospital due to nephrotic syndrome with IgM paraproteinemia. Physical examination demonstrated marked hepatomegaly and anasarca. Serum M-protein was 0.94 g/dl and urinary analysis detected the presence of Bence Jones protein. Bone marrow plasma cell count was 11.2%. Histological examination demonstrated AL-type amyloid deposition in the liver, kidneys, bone marrow, stomach and rectum. These findings led to a diagnosis of IgM multiple myeloma with systemic amyloidosis. Although there was no apparent response to 2 courses of vincristine, doxorubicin and dexamethasone (VAD) regimen, subsequent treatment with bortezomib in combination with dexamethasone resulted in a rapid reduction in M protein to 0.49 g/dl, approximately half the pre-treatment level.