Woman with cryptic chronic back pain: a case report

Abstract

Background: Multiple myeloma is a haematological malignancy often accompanied with monoclonal protein presence in the serum. We present a patient diagnosed with multiple myeloma with negative protein electrophoresis and serum free light chain (sFLC) test which are often used as a first-line screening tests for monoclonal gammopathies. Case Description: A 61-year-old woman presented with chronic lower back pain for the past 2 months with no recent history of fall or trauma. She was investigated for multiple myeloma following her clinical presentation and radiological findings of lytic lesion over her spine, her serum and urine protein electrophoresis with immunofixation as well as sFLC results were negative. She had mild hypercalcaemia but no anaemia and her urea and creatinine levels were within normal range. Patient’s peripheral blood smear showed presence of occasional plasma cells with no rouleaux formation. However, her bone marrow biopsy myelogram revealed 30% medullary plasmocytosis with immunohistochemistry and flow cytometry showed kappa restriction and CD138-positive findings. Conclusions: Serum protein electrophoresis and immunofixation together with sFLC are recommended screening tests for suspected case of multiple myeloma. A negative screening test panel should not be solely used to exclude the diagnosis if the clinical suspicion is high as illustrated in this case.