*Article* **Primary Breast Extranodal Marginal Zone Lymphoma in Primary Sjögren Syndrome: Case Presentation and Relevant Literature**

**Giuseppe Ingravallo 1,\*, Eugenio Maiorano 1, Marco Moschetta 2, Luisa Limongelli 3, Mauro Giuseppe Mastropasqua 1, Gisella Franca Agazzino 1, Vincenzo De Ruvo 2, Paola Tarantino 1, Gianfranco Favia <sup>3</sup> and Saverio Capodiferro <sup>3</sup>**


Received: 14 November 2020; Accepted: 7 December 2020; Published: 10 December 2020

**Abstract:** The association between autoimmune diseases, mostly rheumatoid arthritis, systemic lupus erythematosus, celiac disease and Sjögren syndrome, and lymphoma, has been widely demonstrated by several epidemiologic studies. By a mechanism which has not yet been entirely elucidated, chronic activation/stimulation of the immune system, along with the administration of specific treatments, may lead to the onset of different types of lymphoma in such patients. Specifically, patients affected by Sjögren syndrome may develop lymphomas many years after the original diagnosis. Several epidemiologic, hematologic, and histological features may anticipate the progression from Sjögren syndrome into lymphoma but, to the best of our knowledge, a definite pathogenetic mechanism for such progression is still missing. In fact, while the association between Sjögren syndrome and non-Hodgkin lymphoma, mostly extranodal marginal zone lymphomas and, less often, diffuse large B-cell, is well established, many other variables, such as time of onset, gender predilection, sites of occurrence, subtype of lymphoma, and predictive factors, still remain unclear. We report on a rare case of primary breast lymphoma occurring three years after the diagnosis of Sjögren syndrome in a 57-year-old patient. The diagnostic work-up, including radiograms, core needle biopsy, and histological examination, is discussed, along with emerging data from the recent literature, thus highlighting the usefulness of breast surveillance in Sjögren syndrome patients.

**Keywords:** autoimmune diseases; Sjögren syndrome; minor salivary glands; B-cell lymphoma; extranodal marginal zone lymphoma; MALT lymphoma; primary breast lymphoma
