A rare case of IgDλ/λ free Multiple Myeloma as a virtuous example of collaboration between clinical activity and laboratory medicine

Abstract BACKGROUND: IgD Multiple Myeloma (MM) is a rare hematological neoplasm characterized by an aggressive course compared to the other isotypes of Myeloma; its laboratory findings are usually anemia, presence of Bence Jones protein (BJP), hypogammaglobulinemia, lack of a monoclonal peak on serum protein electrophoresis (SPE), renal failure, osteolytic lesions. CLINICAL CASE: A 72-year-old man with bone pain presented to the Hematology Unit because of bone pain and laboratory tests showing a Monoclonal Component type λ and normocytic anemia (Hemoglobin level 10.5 g/dL). A conventional skeletal radiography of cranium and spine in toto was performed and showed multiple discopathies, sacroiliitis and bilateral coxarthrosis. RESULTS: Laboratory tests performed in Clinical Pathology and Microbiology Unit showed hypogammaglobulinemia, acute renal failure (s-creatinine 2.86 mg/dL, eGFR 39,01 mL/min), s-calcium 9.3 mg/L, serum Free Light Chains ratio 0,0044, presence of BJP type λ, a peak of 19.7 g/L in SPE. Serum immunofixation (sIFE) performed by anti-IgD and λ free serum showed a monoclonal IgDλ band and a monoclonal λ free band. Nuclear Magnetic Resonance (NMR) imaging showed cervical-dorso-lumbar and pelvic osteolysis, while osteomedullary biopsy showed a 70% plasma cell infiltration. Symptomatic IgDλ MM was diagnosed: the symptomatic findings where anemia and bone disease. CONCLUSION: The 72-year-old patient of our clinical case presented at diagnosis some features commonly present in IgD MM. In this case, the laboratory adopted new diagnostic protocols in order to make a correct diagnosis; the hematological parameters, SPE and sIFE were monitored for 56 months. New therapies have been shown to improve outcomes in this disease and a recent revision of recommendations has contributed to good clinical practice for patients with relapsed/refractory MM.