Tacrolimus-Associated Terminal Ileitis After Kidney Transplantation, Mimicking Crohn Disease: A Case Report

: The onset of gastroduodenal ulcers is a frequent complication after transplantation, whereas cases of intestinal ulcers are sporadic and poorly described in the literature. A patient on immunosuppressive therapy with tacrolimus and mycophenolate mofetil after kidney transplant for immunoglobulin A-related glomerulonephritis developed symptoms compatible with Crohn disease 7 months after the transplant. The patient was hospitalized for abdominal pain, diarrhea, fever, and weight loss. Imaging and a colonoscopy showed signs of idiopathic inflammatory bowel disease (IBD) affecting the terminal ileum. Behcet's disease, post-transplant lymphoma, cytomegalovirus, Epstein-Barr virus, or mycobacteria infection were excluded. Mycophenolate mofetil was suspended, and steroid therapy was increased without clinical improvement. Eleven units of blood were required for severe anemia. A further colonoscopy revealed ulcerations involving the cecal fundus, ileocecal valve, and distal ileum with bowel stenosis and suspected ischemia. The patient, therefore, underwent an emergency laparoscopic ileocolic resection. The histologic examination did not reveal clear signs of IBD, ischemia, or viral infection of the ileum. The findings seemed indicative of iatrogenic damage from immunosuppressive therapy. The postoperative course was regular, and after 12 months, the patient was asymptomatic, on low-dose tacrolimus and prednisone therapy. During immunosuppressive therapy, the onset of isolated ileal ulcers, which can mimic IBD, may be a sporadic complication.