Epstein-Barr Virus-Positive Diffuse Large B-Cell Lymphoma Involving the Colon in a Patient With Ulcerative Pancolitis and Polymyositis on Long-Term Methotrexate Therapy.

The link between immunosuppressive therapy and increased lymphoma risk is well established in patients with solid organ transplantation. Epstein-Barr virus-positive (EBV) diffuse large B-cell lymphoma (DLBCL) is known to be a complication in patients receiving methotrexate for rheumatoid arthritis, and the risk of lymphoma in inflammatory bowel disease (IBD) has raised concerns regarding the lymphoproliferative potential of immunomodulatory therapy. In this report, we describe a case of EBV-positive DLBCL arising within the colon of a patient affected by ulcerative pancolitis. The patient is a 73-year-old man with a history of IBD and polymyositis on long-term methotrexate therapy. Increasing age and long-term methotrexate therapy may simulate post-transplantation immunosuppression and contribute to lymphoma tumorigenesis in a segment of chronically inflamed colon.