Intraperitoneal Hemorrhage Caused by a Descending Colonic Arteriovenous Malformation Requiring Emergency Surgery: A Case Report and Literature Review.

INTRODUCTION: Gastrointestinal arteriovenous malformations (AVMs) typically present with luminal gastrointestinal bleeding because they are generally located within the mucosa or submucosa. Intraperitoneal hemorrhage caused by a colonic AVM is exceedingly rare. Herein, we report a rare case of a colonic AVM that presented with intraperitoneal hemorrhage that required emergency surgical intervention.

CASE PRESENTATION: A 59-year-old man presented to a local hospital with left-sided abdominal pain. CT revealed intra-abdominal bleeding, and the patient was subsequently transferred to our institution. Although he was hemodynamically stable on arrival, repeat CT demonstrated an increase in the volume of intra-abdominal hemorrhage. Given the progression of intraperitoneal hemorrhage despite stable hemodynamic status and the absence of a definitive preoperative diagnosis, emergency surgery was performed. Upon laparotomy, approximately 600 mL of hemoperitoneum was identified. A 5-cm area of serosal disruption was observed in the descending colon, and partial colectomy with stapled anastomosis was undertaken. The postoperative course was uneventful, and the patient was discharged on POD 9. Gross examination of the resected specimen revealed an intact mucosal surface, whereas hemorrhage had extended to the serosal surface. Histopathological examination demonstrated irregularly dilated arteries and veins with arteriovenous shunts extending from the deep submucosa to the muscularis propria, confirming the diagnosis of AVM.

CONCLUSIONS: We report a rare case of intraperitoneal hemorrhage originating from a colonic AVM. In this case, bleeding from an AVM extending from the submucosa to the muscularis propria penetrated the serosal surface, resulting in intraperitoneal hemorrhage.