IgD Multiple Myeloma, Does It Still Have a Poor Prognosis?

IgD Multiple myeloma is considered unusual myeloma, with just 2% of cases of MM being diagnosed as IgD subtype. The infrequency of its presentation and the poor prognosis make the disease challenging to treat, with many patients being selected for clinical trials.

A 63-year-old female presented to the ER after falling on ice. After undergoing a CT Head, multiple lytic lesions in the occipital region were found, confirmed by MRI. 2 months later, a bone marrow biopsy found 90% of marrow replaced by CD138 plasma cells, positive for kappa & negative for lambda, consistent with myeloma. On evaluation, she was found to have pan-hypo-gammglobulinemia. However, the skeletal survey did not find any other lytic lesions. Seeing this, IgD levels were measured and found to be >100 times over the upper normal limit with normal beta2-microglobulin levels, confirming monoclonal gammopathy. A FISH study found the patient positive for t(11;14)/CCND1IGH translocation (85% of cells) and negative for TP53. Palliative radiotherapy for the skull base was performed before the patient started chemotherapy. The patient was deemed a suitable candidate, selected for a clinical trial, and placed on RVd [revlimid + velcade + dexamethasone] with delayed bone marrow transplant. As the patient developed a rash and neuropathy from velcade [bortezomib], it was paused and restarted after three months. The patient was doing well on this chemotherapy regimen for two years and was placed on lenalidomide-based maintenance therapy. Two years later, her disease started progressing with an increased frequency of bone pains and opioid dosing. At this juncture, it was decided to change course and start her on pomalidomide/dexamethasone. This did not help the patient, and the neurological side effects of dexamethasone made us change course and initiate a daratumumab, bortezomib, cyclophosphamide and dexamethasone. This proved unfruitful, too, as the patient developed adverse effects of polyneuropathy, pancytopenia requiring transfusion, and worsening GERD. Seeing the disease relapse and intolerance to the previous regimen, we decided to initiate a once-per-week regimen of selinexor, bortezomib, and dexamethasone. The patient has improved on this regimen and is back to her baseline for physical activity, mental status and pain, and an improved appetite.

In this case, we wanted to highlight how incidental findings on a CT lead us to diagnose a rare type of multiple myeloma and how, in the era of novel agents, the survival of patients can be prolonged significantly. Considering the rarity of this subtype, international collaborative studies are suggested to further elucidate the underlying mechanisms for developing potent therapeutic approaches.

Most of the data reported on how IgD multiple myeloma progresses was written before the arrival of novel agents. More evaluation of survival times and progression of the disease needs to be done as it's possible that IgD MM is not as poor a prognosis as it once was.

No relevant conflicts of interest to declare.