IgD-λ myeloma with extensive free light-chain excretion: a diagnostic pitfall in the identification of monoclonal gammopathies

Immunoglobulin D-λ/λ biclonal multiple myeloma: A case report

BACKGROUND

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.

CASE SUMMARY

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.

CONCLUSION

This case highlights the differential clinical manifestations and laboratory findings of IgD-λ/λ myeloma to help minimize the chance of misdiagnosis.

Immunoglobulin D-kappa multiple myeloma in a patient with rheumatoid arthritis: a case report and review of the literature

A 77-year-old Japanese woman with a 21-year history of seropositive, erosive rheumatoid arthritis (RA) and a 10-year history of methotrexate (MTX) therapy was admitted with malaise and mild consciousness disturbance. Laboratory data showed hypercalcemia, acute kidney injury, normocytic anaemia, and thrombocytopenia. As we first assumed drug-induced toxicity by MTX and eldecalcitol, both were discontinued and leucovorin rescue therapy and calcitonin were administered. However, her condition continued to worsen. Serum protein electrophoresis showed only a small M-peak, immunoelectrophoresis of both the serum and urine demonstrated Bence-Jones kappa (κ) type monoclonal protein without immunoglobulin heavy chain, and bone marrow examination revealed proliferation of plasma cells. We diagnosed her with Bence-Jones κ type multiple myeloma (MM) and transferred her to the department of haematology of a higher order medical institution. Conclusively, the diagnosis of immunoglobulin (Ig) D-κ type MM, a rare variant of this disorder, was determined in accordance with serum immunofixation. Several previous studies have suggested that pre-existing RA is a risk factor for MM. Although IgD MM is characterised by its clinical severity and poor prognosis compared to other subtypes, it is often misdiagnosed or mistaken as light chain type MM, as in the present case, because of the low level of IgD M-protein, resulting in delayed diagnosis. Physicians must take MM into consideration as a differential diagnosis when inactive RA patients present with inexplicable elevated calcium, renal failure, anaemia, and bone lesion symptoms and should be aware of IgD MM to establish the correct diagnosis promptly.

Presentation Patterns, Diagnostic Markers, Management Strategies, and Outcomes of IgD Multiple Myeloma: A Systematic Review of Literature

Immunoglobulin (Ig) D multiple myeloma (MM) is a rare subtype of MM comprising 2% of all the cases. Malignant plasma cell invasion leads to signs and symptoms similar to other subtypes of MM. The synthesis rate of IgD is lower in IgD MM patients, making it very difficult to diagnose compared to other subtypes. As there is no available diagnostic test with 100% accuracy, the diagnosis of IgD MM is based on multiple factors. Recent advances in the treatment have resulted in a better overall survival for IgD MM patients. The aim of this systematic review was to summarize the data on presentation patterns, diagnosis modalities, management strategies, and outcomes in patients with IgD MM.