Sjögren's syndrome associated with multiple myeloma.

Sjögren's syndrome (SS) is a chronic autoimmune disease of unknown etiology characterized by lymphocytic infiltration of the exocrine glands and a polyclonal B-cell activation; it is demonstrated by the presence of multiple autoantibodies against organ- and non-organ-specific autoantigens. SS is associated with malignant lymphomas, Waldenstrom's macroglobulinemia and benign monoclonal gammopathy, while its relationship with multiple myeloma is extremely rare. The association between multiple myeloma and rheumatoid arthritis and other autoimmune diseases has been established, but it is not clear why a B-cell proliferation like myeloma occurs more rarely than other B-cell disorders in patients with SS. We describe a patient who presented with multiple myeloma and SS that might have existed for at least 2 years prior to the appearance of myeloma.