A Protean Protein

• If a monoclonal protein is suggested by SPEP but cannot be identified by standard immunofixation, request immunofixation for IgD or IgE. Screen patients for IgD and IgE paraproteins before making a diagnosis of light chain multiple myeloma.
• Polyclonal gammopathy or reduced renal clearance with accumulation of free light chains in the serum may mask the presence of low levels of monoclonal FLC and result in a normal sFLC ratio.
• Thrombosis is a less-recognized but documented feature of POEMS syndrome which may be mediated by the overproduction of proinflammatory and proangiogenic cytokines, though the precise pathogenesis is unknown.

Acknowledgment

The authors thank Dr. Theodore Kurtz and Dr. Anne Deucher from the department of laboratory medicine at the University of California, San Francisco for providing their respective expertise in clinical chemistry and hematopathology.

Disclosures

The authors have no conflicts of interests to disclose.

1. Rajkumar SV, Dimopoulos MA, Palumbo A, et al. International Myeloma Working Group. International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma. Lancet Oncol. 2014;15(12):e538-ee548. doi: 10.1016/S1470-2045(14)70442-5.