A case of secondary plasma cell leukemia resistant to novel agents, in which stringent complete remission was achieved and maintained for a long period of time after VAD therapy and tandem autologous transplantation.

A 61-year-old woman was diagnosed in June 2011 as having immunoglobulin G (IgG) ĸ-type multiple myeloma (MM), stage II, according to the International Staging System (ISS). Chromosome analysis showed a complex karyotype, including t(11;14) and del 13q. Analysis of the cell surface markers revealed that the cells were positive for mature plasma cell-1 (MPC-1), and negative for cluster of differentiation (CD) 45 and CD49e, suggestive of an intermediate level of maturity of the cells. The disease was refractory to bortezomib-dexamethasone (BD) therapy and progressed to plasma cell leukemia despite the treatment. Treatment was therefore switched to lenalidomide-dexamethasone (RD) therapy, however, the condition again proved to be refractory to this therapy. A partial response (PR) was achieved with vincristine-doxorubicin-dexamethasone (VAD) therapy. The residual plasma cells became CD45-positive, suggesting a change of the cells from an intermediate level of maturity to mature cells. In December, autologous peripheral blood stem cell transplantation (Auto-PBSCT) was performed after high-dose melphalan therapy (melphalan 200 mg/m(2)) as pretreatment. PR was observed and a second Auto-PBSCT was performed in July 2012. Stringent complete remission (sCR) has been maintained for 2 years since, without any further treatment. This is the first reported case of secondary plasma cell leukemia (sPCL) resistant to new drugs that was successfully treated by high-dose melphalan in combination with VAD therapy and Auto-PBSCT.