Massive lower gastrointestinal bleeding from an external iliac artery fistula in a patient with bladder cancer.

Arterioenteric fistula is a rare cause of lower gastrointestinal bleeding, yet it can potentially cause massive, life-threatening bleeding. Patients with an advanced pelvic malignancy can develop hemorrhage from an arterioenteric fistula. Selective mesenteric angiography is unable to demonstrate the source of bleeding in these patients, so evaluation of the iliac arteries is essential. We present a 67-year-old man with advanced bladder cancer presenting as massive, life-threatening lower gastrointestinal bleeding from an external iliac arterial fistula to the cecum.