Abstract
We encountered a rare a case of isolated internal iliac aneurysm-rectal fistula. The patient was an 86-year-old man and his chief complaint was irregular bowel movement. Upon admission, he developed fresh melena. Contrast-enhanced computed tomography demonstrated a 4.5-cm-diameter right internal iliac arterial aneurysm and an adherent cystic mass 6 cm in diameter compressing the rectum. An aorto-enteric fistula was highly suspected and emergency surgery was performed. Pseudoaneurysm from the right internal iliac aneurysm adhered tightly to the rectum and aneurysm wall and the rectum was resected en-bloc. Branches of the internal iliac aneurysm were closed from inside the aneurysm. The abdominal aorta was reconstructed with Y-shaped ePTFE graft and a Hartmann operation was done. His postoperative course was uneventful. Pathological examination revealed rupture of the right internal iliac aneurysm penetrating into the submucosal layer of the rectal wall. The rectal mucosa became ischemic, suggesting that herald bleeding might have been due to mucosal bleeding caused by ischemia.
