Non-secretory multiple myeloma in a patient with chronic kidney disease

Multiple myeloma (MM) ) is a malignant plasma cell disorder from the group of monoclonal gammopathies. One of the most frequent diagnostic findings is the M-spike in serum protein electrophoresis (SPEP), which is notably absent in a rare non-secretory subtype of this disease.

A case report describes a 55-year old woman with a history of chronic kidney disease (CKD) in stage 3, proteinuria, asthma and Graves' disease. She presented for a diagnosis of proteinuria (of 2,2 g/24 h). Her SPEP was normal, and she underwent a kidney biopsy, which showed mild glomerulal abnormalities. She returned to the clinic after 5 years with progression of CKD (between hospitalizations creatinine rose from 1,27 mg/dl to 2,8) and proteinuria (2,7 g/24 h). She had normocytic anemia, normocalcemia and normal ESR. The SPEP showed no suspicious findings, but suspecting multiple myeloma, immunofixation was performed. It showed excessive levels of kappa FLC in serum and urine. A bone marrow biopsy showed plasmocytes characteristic for MM in both number and phenotype. No osteolytic lesions were shown in diagnostic imaging, and beta-2-microglobulin was elevated to 6,5 μg. Thus, the patient was diagnosed with ISS stage 3 multiple myeloma and referred to a hematology clinic for treatment.

The diagnosis of atypical cases of multiple myeloma may pose a difficulty to clinicians. Knowledge of diagnostic tests is required to introduce proper treatment.