LAUSR

OBJECTIVE Primary aortoenteric fistulas (PAEFs) are a rare entity with high morbidity, and their relationship with Bacillus Instillation of Calmette-Guérin is anecdotal. METHODS/RESULTS We present a 68-year-old male with a primary aortoenteric fistula after instillation of Bacillus Calmette-Guérin (BCG) for a non-muscle-invasive bladder cancer. Diagnosis was made by CT angiography, subsequently confirmed by intraoperative findings and results of anatomopathological studies of aortic wall samples. We performed an in-situ reconstruction with a silver prosthesis impregnated in rifampicin with satisfactory evolution at one year. CONCLUSIONS Primary aortoenteric fistula is an extremely rare complication, and although its relationship with intravesical BCG therapy is anecdotal, it should be considered in patients with gastrointestinal bleeding who have previously undergone this treatment. Its diagnosis requires clinical suspicion, and its treatment should be carried out without delay. Long-term targeted anti-biotherapeutic treatment is a fundamental pillar for its management. Reconstruction with an antibiotic-impregnated silver prosthesis is a valid option in cases of controlled infection.