Vasculitis and Sjögren's syndrome with IgA-IgG cryoglobulinemia terminating in immunoblastic sarcoma.

Generalized lymphadenopathy and other manifestations of Sjögren's syndrome developed in a 68 year old woman with a long history of systemic vasculitis and arthralgia. An unusual immunologic feature was hypogammaglobulinemia and immunoglobulin A (IgA) monoclonal immunoglobulinemia with mixed IgA-IgG cryoglobulin. At autopsy, the histopathologic findings were compatible with immunoblastic sarcoma. The monoclonal IgA protein, found in serum, pleural and pericardial fluids, showed rheumatoid factor activity. Immunocytes from the immunoblastic sarcoma were found to be the source of the monoclonal IgA protein.