A Curious Case of Multiple Myeloma Hidden in a Cloud of Severe Cryoglobulinemia

Cryoglobulins are proteins that form ‘cloudy’ precipitates at temperatures <37°C. In type I cryoglobulinemia, the causative protein is a monoclonal immunoglobulin due to an underlying plasma cell dyscrasia. Cryoglobulinemia can present with hyperviscosity syndrome, characterized by headache, fatigue, and blurred vision. In episodes of severe cryoglobulinemia, premature precipitation of proteins can lead to falsely negative diagnostic tests and complications with treatment. The following case exemplifies the complications of diagnosis and treatment of cryoglobulinemia with hyperviscosity syndrome.