Abstract
Isolated internal iliac artery aneurysms are rare and at high risk of rupture with an associated high mortality. We report 2 cases of ruptured isolated internal iliac artery aneurysm presenting with rectus sheath hematoma in the lower abdomen with difficult diagnoses. Case 1: A 77-year-old man presented with lower abdominal pain. A computed tomography (CT) scan revealed an isolated aneurysm of the right internal iliac artery and a hematoma expanding from the outer layer of the peritoneum beneath the lower rectus abdominis muscle, through the bladder to the right pelvic retroperitoneum. However, there was no evidence of hematoma around the aneurysm and thus a definitive diagnosis of rupture was not made. On Day 2, exacerbation of his anemia was noted and an explorative laparotomy was performed which revealed a rupture at the base of the aneurysm. The blood flow was blocked from within the aneurysm, and aneurysmorrhaphy was performed but the patient died from a postoperative complication of pneumonia. Case 2: A 76-year-old man who presented with lower abdominal pain underwent a CT scan that revealed an isolated left internal iliac artery aneurysm with a small surrounding hematoma, and a rectus sheath hematoma in the lower abdomen, and thus we diagnosed a ruptured aneurysm. The blood flow was blocked from within the aneurysm, and aneurysmorrhaphy was performed. The patient was discharged without complications. Although rapid diagnosis and appropriate treatment are needed for ruptured aneurysms to improve the survival rate after rupture, diagnosis is difficult in atypical cases of a rare disease without evidence of hematoma around an aneurysm. If a ruptured aneurysm is suspected, exploratory laparotomy should be performed.
