Sjögren syndrome associated with multiple myeloma of the IgA κ-type

Abstract We report a case of a 62-year-old female patient with Sjögren syndrome (SS) who developed multiple myeloma (MM) of the IgA κ-type. In 1986, the patient was admitted to our hospital with a facial rash, keratoconjunctivitis sicca, and xerostomia. She was diagnosed as having discoid lupus erythematosus (DLE) and SS. She was treated with bromhexine hydrochloride for SS and with topical fluorinated steroid for DLE. In 1992, she developed compression fractures of the lumbar vertebrae and was readmitted to our hospital. DLE was not recognized. Laboratory findings revealed IgA 2046 mg/dl, IgG 529 mg/dl, and IgM 21 mg/dl. Anti-SS-A antibody was 1 : 32 and anti-SS-B antibody was 1 : 2. M protein of IgA κ was demonstrated by immunoelectrophoresis. Aspiration biopsy of the bone marrow revealed 20.2% plasma cells. A bone scintigram demonstrated many hot spots at the cervical and lumbar vertebrae. She was diagnosed as having SS and MM of the IgA κ-type. After chemotherapy for MM, the percentage of plasma cells in the bone marrow and the concentration of serum IgA decreased to 6.2% and 532 mg/dl, respectively. SS is frequently associated with benign monoclonal gammopathy or lymphoproliferative disorders, especially Waldenström's macroglobulinemia or malignant lymphoma. Although benign monoclonal gammopathy has frequently been observed in patients with SS, SS associated with MM is extremely rare.