Fibrin-Associated Large B-Cell Lymphoma Mimicking Pyogenic Spondylitis After Abdominal Aortic Graft Infection

Case: A 75-year-old man with prior abdominal aortic graft replacement was treated for suspected graft infection involving the lumbar spine. Persistent inflammation despite antibiotics and posterior fusion led to anterior debridement through a retroperitoneal approach with iliac bone grafting. Histopathology revealed fibrin-associated large B-cell lymphoma (FA-LBCL). His condition deteriorated, precluding further surgery or chemotherapy, and he died after transfer for palliative care. Conclusion: FA-LBCL, a rare entity often detected histologically in surgical specimens, is associated with fibrin deposition from chronic inflammation or infection. Given its clinical similarity to infectious bone lesions, pathological evaluation should be considered if infection treatment fails.