Inferior Vena Cava Graft–Enteric Fistula Presenting with Occult Gastrointestinal Bleeding and Psoas Abscess: A Rare Case Report

Background: Inferior vena cava (IVC) graft–enteric fistula is an exceptionally rare but potentially fatal complication of caval reconstruction. Case Presentation: A 22-year-old woman with previous IVC and right renal vein reconstruction presented with an 18-month history of intermittent abdominal pain, diarrhea, and progressive anemia. On admission, contrast-enhanced computed tomography demonstrated a thrombosed IVC graft with perigraft gas and fluid, loss of the fat plane between the graft and adjacent bowel, and a multiloculated right psoas abscess. Escherichia coli was isolated from blood and drainage cultures. Upper gastrointestinal endoscopy directly visualized prosthetic graft material protruding into the descending duodenum, confirming a graft–enteric fistula. After targeted antimicrobial therapy and stabilization, the patient underwent complete graft explantation, resection of the involved duodenal and jejunal segments, duodenojejunal reconstruction, and extensive retroperitoneal debridement. She remained free of recurrent infection, fistula, and gastrointestinal bleeding at 5-year follow-up. Conclusions: In patients with previous caval reconstruction, persistent gastrointestinal symptoms, unexplained anemia, bacteremia, or retroperitoneal infection should raise suspicion for a graft–enteric fistula. Computed tomography may identify suggestive perigraft changes, whereas endoscopy can provide direct confirmation of luminal erosion.