Small Bowel Perforation as an Initial Manifestation of Immune Deficiency and Dysregulation-Associated Lymphoma in a Patient With Rheumatoid Arthritis: A Case Report.

Lymphoid proliferation and lymphomas associated with immune deficiency and dysregulation (IDD-LPD and lymphomas) are rare entities that occur in patients with autoimmune diseases, such as rheumatoid arthritis (RA) on immunosuppressant medications. Herein, we report a case of a 66-year-old woman diagnosed with IDD lymphoma after emergency laparotomy for ileal perforation. She had a history of RA, had been treated with antirheumatic drugs for 15 years, and was recently suspected of having gastric cancer with multiple liver metastases by her primary care physician. The patient was referred to our hospital because of severe abdominal pain. Computed tomography (CT) revealed peritonitis with intra-abdominal free air, and emergency laparotomy was performed. Intraoperative findings revealed multiple nodules in the ileum with two perforations, in addition to a gastric tumor and multiple liver tumors. Partial resection of the perforated ileum and anastomosis were performed. Histopathological examination of the resected ileum confirmed diffuse large B-cell lymphoma, leading to a diagnosis of IDD-lymphoma. Antirheumatic drugs were discontinued after diagnosis. Although the liver lesions shrank after discontinuation, Gallium-67 scintigraphy showed diffuse liver uptake. After careful discussion with hematologists, chemotherapy was administered (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone, six cycles). One year after chemotherapy, the patient remained in remission, and her RA symptoms were stable without antirheumatic drugs.