Ilio-rectal fistula : a rare cause of lower gastrointestinal bleeding: case report and literature review

Primary ilio-enteric fistulas are rare vascular conditions that may present with aspecific symptoms. We report here a case of a left internal iliac artery aneurysm fistulized to the rectum and provide a review of the literature to highlight the variability of clinical presentations and therapeutic options. An 81-year-old man with a history of pelvic irradiation and surgery for prostate carcinoma presented to the emergency department with lower gastrointestinal bleeding. Imaging revealed a fistulization of a left internal iliac artery aneuvrysm into the rectum. He underwent open surgical treatment, consisting of exclusion of the aneurysm, primary arterial closure without graft interposition, and a Hartmann’s procedure. This case highlights that biphasic bleeding should raise high suspicion in patients with history of pelvic radiotherapy or surgery, or a known pelvic aneurysm, even if its size is below the treatment threshold. The reviewed literature illustrates the importance of individualized, multidisciplinary decision-making and the need to consider rare diagnoses when faced with atypical presentations of lower gastrointestinal bleeding.