[Primary Sjögren's syndrome presenting as unconsciousness associated with IgA-lambda M-protein].

We describe the case of a 43-year-old woman who presented with primary Sjögren's syndrome (SS) which manifestated as unconsciousness due to M protein. A diagnosis of SS was made based on a ten-year history of dryness, a Shirmer test, and the histological findings of labial biopsy. A rouleaux formation was observed and serum protein electrophoresis revealed a monoclonal spike of 4.0 gm/dl in the gamma-region, which was characterized as IgA-lambda. Biopsy of the minor salivary glands showed marked polyclonal lymphoproliferation with lymphoid follicles, including both T cells and B cells as revealed by immunohistological staining. Therefore, the patient had a lymphoproliferative lesion of the minor salivary glands, which is also known as pseudolymphoma. We conclude that fainting associated with marked M protein may be manifestation of SS. Such cases should be followed carefully since the subsequent neoplastic transformation of pseudolymphomas have been previously reported.