Pseudo-monoclonal gammopathy due to autoimmune disease: a case report.

Hyperglobulinemia is a common manifestation of plasma cell disease, and it is sometimes caused by autoimmune diseases (AIDs). We report an uncommon presentation of hyperglobulinemia, with a high amount of plasma cells in bone marrow, pancytopenia, hematemesis, and splenomegaly in an 18-year-old woman. Some examinations were performed to determine the diagnosis, including serum protein electrophoresis, immunofixation electrophoresis, the free light chain assay, abdominal enhanced computed tomography (CT) and CT venography, and positron-emission tomography-CT. The patient was finally diagnosed with AID. Considerable improvement in her symptoms was observed after immunosuppressive therapy. Findings in this case highlight that not only differentiation of hyperglobulinemia caused by monoclonal or polyclonal immunoglobulin, but also AIDs, need to be considered to exclude non-Hodgkin's lymphoma and plasma cell disease.