Small-cell lymphoma and Sjögren's syndrome. Lymphoplasmacytic subvariant of small-cell lymphoma with IgA/kappa immunoglobulin surface markers.

To our knowledge, the association of the plasmacytoid variety of small-cell lymphoma with primary Sjögren's syndrome has not been reported. We describe a patient with SS who developed plasmacytoid small-cell lymphoma. As opposed to the commonly detected IgM, the lymphocyte surface immunoglobulins contained monoclonal IgA/kappa light chains. In addition to the unique immunopathologic features, the impressive response to chemotherapy and the importance of surface immunoglobulin markers in the diagnosis of malignancy in Sjögren's syndrome are discussed.