Abstract
The sigmoid colon is an uncommon site for the origin of primary malignant lymphomas in the GI tract. Additionally, immunosuppressive agents, widely used in treating autoimmune diseases, have been associated with the induction of malignancies, including lymphoproliferative disorders. In this report, we present a rare case of GI perforation suggesting a link between immunosuppressive therapy, particularly tacrolimus treatment, and diffuse large B-cell lymphoma (DLBCL). A 75-year-old female patient presented with abdominal pain to our ER. She had a medical history of polymyositis and interstitial pneumonia, treated with the immunosuppressant tacrolimus. An abdominal CT scan revealed free gas in the abdominal cavity, leading to a diagnosis of GI perforation. The patient exhibited generalized peritonitis and underwent emergency surgery the same day. During surgery, a perforation in the sigmoid colon was identified, and a Hartmann procedure was performed. Postoperative pathology showed CD20+, CD30+, CD5-, CD10-, BCL6+, MUM1+, and MIB-1 LI of 50-60%. The diagnosis of DLBCL was confirmed, classified as EBV-positive diffuse large B-cell lymphoma, not otherwise specified (NOS), in the sigmoid colon, with positive EBER-ISH, LMP-1, and EBNA2 findings. Given her history of immunosuppressant use, she was categorized as having other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-LPD), according to the WHO Classification of 2017. This case highlights the importance for clinicians to consider the risk of oncogenesis associated with the prolonged use of immunosuppressive agents.