Waldenström's macroglobulinemia.
A 71-year-old man presented with palpable purpura and received a diagnosis of type II cryoglobulinemia. He had an elevated cryocrit (13%), evidence of a monoclonal IgM kappa immunoglobulin (0.8 g per deciliter), and a positive result for rheumatoid factor. A specimen from a bone marrow biopsy showed less than 1% plasma cells, and serologic testing for hepatitis C was negative. Sixteen months after diagnosis, he was admitted for progressive renal disease. A repeat bone marrow biopsy revealed a hypercellular marrow with 15% monotypic IgM kappa–restricted plasma cells, confirming a diagnosis of Waldenström's macroglobulinemia. He was treated with rituximab and therapeutic plasma exchange but was lost to follow-up after hospital discharge. Four months later, he presented with altered mental status and progressive ischemic injury of the toes, the fingers, the superior aspect of the ears, and the tip of the nose, probably related to hyperviscosity and cryoglobulinemic vasculitis. He required amputation of the digits and since presentation about 1 year ago has been treated with intravenous immunoglobulin, rituximab, and therapeutic plasma exchange.
