Primary colonic MALT lymphoma associated with Crohn's disease: Case report and review of the literature

KEY CLINICAL MESSAGE: To date, the pathogenic mechanisms of the association between Crohn's disease and MALT lymphoma are ambiguous and yet remain to be elucidated. The publication of other cases illustrating this rare association would be interesting to properly plan therapeutic strategies and to better understand the pathogenesis and the prognosis of this association. ABSTRACT: Crohn's disease is a progressive disease, with increasing incidence, that leads to bowel damage and disability. Primary colonic MALT lymphoma is a low‐grade B lymphoma, representing only 2.5% of all MALT lymphomas. The pathogenesis of these two cancers is still not clearly elucidated and their association is rare. To our knowledge, only two cases have illustrated synchronous Crohn's disease and MALT lymphoma. The possible role of Crohn's disease as a precursor of MALT lymphoma is still debated; some studies proposed that immunosuppressive drugs used in Crohn's disease are involved in the lymphomagenesis of MALT lymphoma. Other studies supposed no relation between these two neoplasms. We present a rare case of association between Crohn's disease and primary colonic MALT lymphoma in an elderly female patient who had not received any immunosuppressive therapy. The patient presented with chronic diarrhea, epigastric pain, and weight loss. A colonoscopy with biopsies was performed. The histopathologic examination concluded with the diagnosis of not only Crohn's disease but also MALT lymphoma. This discovery of MALT lymphoma was incidental. We highlight the clinical and histopathological features, and we discuss the association between Crohn's disease and MALT lymphoma, which may provide additional information about pathogenic mechanisms.