Cryocrystalglobulinemia mimicking rheumatoid arthritis and vasculitis.

We describe a patient with longstanding arthropathy resembling rheumatoid arthritis (RA) and cold induced purpura for many years, concomitant with IgG kappa paraproteinemia. At autopsy, the patient was found to have evidence of widespread vascular occlusions due to precipitated crystals as well as tissue deposition of crystals. Neither vasculitis nor synovitis was observed despite the clinical picture of both. Blood and synovial fluid obtained antemortem were found to spontaneously form crystals when stored at 4 degrees C, and the washed crystals were composed of the same monoclonal IgG kappa previously found in serum. Cryocrystal formation occurred at 33 degrees C and neutral pH. This patient thus had cryocrystalglobulinemia mimicking clinical manifestations of RA and vasculitis.