Published online Apr 16, 2021. doi: 10.12998/wjcc.v9.i11.2576
Peer-review started: December 8, 2020
First decision: December 30, 2020
Revised: January 11, 2021
Accepted: February 4, 2021
Article in press: February 4, 2021
Published online: April 16, 2021
Immunoglobulin D (IgD) multiple myeloma (MM) is a rare subtype of MM and commonly occurs in younger subjects but at a later stage of the International Staging System (ISS) when admitted. As a special type of IgD myeloma, IgD-λ/λ biclonal MM is rarer. Its serum protein electrophoresis and serum immuno-fixation electrophoresis (IFE) might find no anomalies even if the bone marrow (BM) examination is performed. Thus, it is easy to miss the diagnosis.
A 62-year-old man diagnosed as IgD-λ/λ myeloma (ISS stage III) was admitted with fatigue and weight loss. The physical examination suggested an anemic face, a few moist rales at the left lung base, and mild concave edema in both lower extremities. Laboratory examinations showed the elevated creatinine levels, β2-microglobulin, lactic dehydrogenase, and erythrocyte sedimentation rate, while the decreased neutrophils, granulocytes, and hemoglobin. In the serum protein electrophoresis, there appeared two inconspicuous M-spikes. Serum IFE indicated an over-representation of lambda light chain and yielded two monoclonal bands in λ region, but only one corresponding heavy chain band in the antisera to IgD region. The BM histology and BM cytology both supported the diagnosis of IgD-λ/λ myeloma.
This case highlights the differential clinical manifestations and laboratory findings of IgD-λ/λ myeloma to help minimize the chance of misdiagnosis.
Core Tip: Immunoglobulin D (IgD)-λ/λ myeloma is extremely rare and has a later International Staging System stage at diagnosis. The median survival time is shorter than that of other subtypes, and renal insufficiency is prone to occur at the time of diagnosis. Furthermore, the laboratory examination tends to consider IgD-λ/λ myeloma as other isotypes in that its serum immunofixation electrophoresis shows two bands in the λ region but no responding heavy chain band. Therefore, more complete serum immunofixation electrophoresis should be conducted to reduce the rate of missed diagnoses.