This case report is a useful account of an unusual presentation of IgD myeloma. Because of the prognostic differences that exist between IgD myeloma and other more common forms of the malignancy, recognition of this paraprotein is important. Without the laboratorian's involvement, this diagnosis can easily be delayed or missed.
The authors followed all of the steps that should be taken in a case such as this. They noted the polyclonal immune paresis although the globulin fraction was normal and proceeded to immunofixation of the serum because there was a small band in the β region. In my experience, a distinct band might not always be visible on simple electrophoresis, and therefore immunofixation is always indicated in cases where the polyclonal immunoglobulins are suppressed. Once a monoclonal light chain was identified, the authors were correct to look for IgD and IgE heavy chains—particularly so in this case, where monoclonal λ light chains are involved, given the preponderance of λ light chains in IgD myeloma. Examination of urine for the presence of Bence Jones proteinuria should be a mandatory procedure in cases like this.
A more general clinical point should be made about the investigation of anyone with a “pathological bone fracture.” The possibility of myeloma was not investigated earlier, although there was clear evidence of rib fractures a year previously, presumably because of the patient's age and otherwise nonspecific symptoms. Regardless of the patient's age, if there is a pathological fracture, an immunoglobulin profile then becomes an essential part of the workup of that patient.
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Authors' Disclosures of Potential Conflicts of Interest: No authors declared any potential conflicts of interest.
Role of Sponsor: The funding organizations played no role in the design of study, choice of enrolled patients, review and interpretation of data, or preparation or approval of manuscript.
- Received for publication April 12, 2010.
- Accepted for publication April 13, 2010.
- © 2010 The American Association for Clinical Chemistry