[Light chain escape followed by leukemic transformation in a patient with IgD myeloma]

A 63-year-old male with multiple myeloma (IgD-λ) received autologous peripheral blood stem cell transplantation (PBSCT) after induction of VAD in March 2008, and obtained a very good partial response. However, he required BOR/DEX and a second PBSCT for relapse, and in August 2012, treatment with LEN/DEX was started. After 4 cycles of LEN/DEX, IgD decreased but FLC-λ increased paradoxically, indicating a clonal change. In January 2013, an LCD regimen was started and after 4 cycles, IgD showed normalization, but his condition worsened as FLC-λ increased. This case showed a fulminant clinical course with light chain escape in this era of treating multiple myeloma with novel agents.