Multiple myeloma revealed by a pulmonary embolism, with more anodal migration of λ IgG in the β2 region on serum protein electrophoresis.

Abstract

Introduction: Serum protein electrophoresis (SPE) is widely used to detect monoclonal gammopathies and other hematologic or inflammatory disorders. IgG monoclonal proteins typically migrate in the gamma region, while IgA frequently migrates in the beta region. However, IgG migration in the β₂ region is an exceptionally rare occurrence that can pose significant diagnostic challenges.

Case presentation: We present the case of a 76-year-old woman who was initially diagnosed with acute bilateral pulmonary embolism and deep vein thrombosis as the first clinical manifestation of multiple myeloma. Laboratory findings revealed hypercalcemia, mild anemia, and a monoclonal IgG lambda peak in the β₂ region, which was confirmed by immunofixation. Echocardiography revealed left ventricular dilation with preserved right-sided heart structures. Ten days later, the patient developed cauda equina syndrome due to spinal involvement, requiring urgent surgical decompression.

Discussion: This case highlights three exceptionally rare and clinically significant features: (1) IgG monoclonal protein migration in the β₂ region, (2) pulmonary embolism as the first manifestation of multiple myeloma, and (3) severe skeletal complications after minimal trauma. Clinicians should consider underlying monoclonal gammopathy in unexplained thromboembolic events and exercise caution when interpreting atypical SPE patterns, which may be crucial for early diagnosis. The unusual combination of these findings underscores the importance of a comprehensive approach to diagnosing plasma cell disorders.

Conclusion: Recognition of more anodal IgG migration and awareness of thromboembolic presentation are crucial to ensure early diagnosis and appropriate management of multiple myeloma.