Among autoimmune diseases, Sjogren's syndrome (SS) displays the highest 
incidence of non-Hodgkin lymphoma (NHL) development with the salivary extranodal 
marginal zone B cell lymphomas being the most common type. The majority of 
SS-associated NHLs are characterized by localized stage, indolent clinical 
course, and recurrence in other extranodal sites. Although the transition from a 
chronic inflammatory condition to malignant lymphoma is a multistep process yet 
poorly understood, there is increasing evidence that chronic antigenic 
stimulation by an exoantigen or autoantigens plays an essential role in the 
development of SS associated lymphoproliferation. Additional molecular oncogenic 
events such as microsatellite instability, loss of the B cell cycle control, and 
the forced overproduction of specific B cell biologic stimulators seem to 
contribute to the emergence and progression of the malignant overgrowth. Among 
the clinical and serological parameters that have been associated with lymphoma 
development in SS patients, the presence of palpable purpura, low C4, and mixed 
monoclonal cryoglobulinemia constitute the main predictive markers, and patients 
displaying these risk factors should be monitored closely.