Spontaneous Tumoural Regression in a Patient with t(4;14) Translocation Multiple Myeloma. A Case Report.

INTRODUCTION Despite recent advances, multiple myeloma continues to be an incurable malignancy, with a median overall survival (OS) of 29–62 months. A shortened survival is seen in myeloma patients having a t(4;14) translocation either with standard or high-dose chemotherapy (median OS 26 and 33 months, respectively). CASE REPORT A 60 year-old female was found to have a high ESR (121mm/h) and low hemoglobin (113g/L) in December 2005. Further work-up led to the diagnosis of stage 1A (Durie-Salmon) multiple myeloma on the basis of the following investigations:

1. a protein electrophoresis showed IgG 12.2g/L, IgA 23.4g/L and IgM 0.33g/L with an IgA-kappa paraprotein;

2. a bone marrow biopsy revealed 20–30% infiltration with atypical plasma cells, kappa restricted; IGH-MMSET fusion transcripts were detected by RT-PCR, consistent with the presence of t(4;14) positive cells in the specimen;

3. a metastatic survey showed generalized osteopenia throughout the axial skeleton and multiple subtle permeative lucencies in the proximal humeral diaphyses bilaterally.

A 24-hour urine collection showed 0.05g/L proteinuria with no Bence-Jones proteins detected. Her peripheral blood counts were as follows: hemoglobin 118g/L (MCV 91fL), platelets 275 bil/L and white blood cells 6.6 bil/L with 3.9 neutrophils and 1.8 lymphocytes. Her electrolytes and calcium were within normal limits but she had a slightly elevated creatinine at 107umol/L (normal <99). Her b₂-microglobulin, C-reactive protein and albumin were all normal at 219nmol/L (normal ≤219), 4mg/L (normal ≤12) and 36g/L (36–50) respectively. No active therapy was recommended apart from monthly PAMIDRONATE for permeative lucencies. Her past medical history was significant for an IgA cryoglobulinemia diagnosed in 1985 when she presented with arthritis, purpura and Raynaud’s phenomenon. Her cryocrit has been ranging from 0–25% over the years; most recently still at 5%. She did not require any treatment until 1989 when she was started on low dose-steroids. Her flares consist mainly of lower limbs arthritis and purpura and they have been treated with intermittent PREDNISONE 5–7.5mg per day. A progressive drop in her M-protein has been documented since June 2006 with her most recent protein electrophoresis revealing no paraprotein, quantitative IgG is 7.7g/L, IgA 2.23g/L and IgM 0.63g/L. A bone marrow biopsy has shown less than 5% plasma cells. Her peripheral blood counts and biochemistry remained within normal limits and her skeletal survey is unchanged. A 24-hour urine collection shows no significant proteinuria (0.07g/L). Her free light chains assay revealed kappa 13.8mg/L and lambda 11.0mg/L with a ratio kappa/lambda 1.3.

CONCLUSIONS We have documented tumoural regression in a patient with IgA-kappa multiple myeloma and t(4;14) only receiving intermittent low dose PREDNISONE and monthly PAMIDRONATE. This exceptional phenomenon has been well described with other malignancies such as testicular germ cell tumours, hepatocellular carcinomas and neuroblastomas; however, to the best of our knowledge, only in 2 cases of multiple myeloma. The unusual nature of this finding is highlighted by the presence of the t(4;14) in the plasma cells, known to be associated with more aggressive disease. The underlying mechanisms, speculated to be immunological for most of the other cancers, remain completely unknown in this case.