Plasma cell myeloma positive for t(14;20) with relapse in the central nervous system

t(14;20)(q32;q11)/IGH-MAFB is a rare chromosomal abnormality in plasma cell myeloma (PCM), accounting for 1-2% of PCM cases. Patients with this translocation may have a poor prognosis. However, the clinicopathological features and response to novel agents have not been well clarified. We present a 63-year-old Japanese female with PCM positive for t(14;20). The tumor responded well to a proteasome inhibitor, bortezomib, and the patient achieved complete remission. Six months after remission, tumor relapse was noted in the left cerebellum and the right frontal lobe of the cerebrum. After whole brain radiation therapy, the tumor masses decreased in size. The patient was followed up with best-care support, but died of the disease 29 months after the initial PCM diagnosis. t(14;20)-positive PCM responded well to bortezomib at the time of the initial treatment. The CNS tumor involvement, which is rare in PCM, may be associated with the clinical aggressiveness of the t(14;20)-positive form of this myeloma.