Rectal Cancer Complicated by a Pelvic Arteriovenous Malformation Managed with Preoperative Embolization and Robotic Surgery: A Case Report

INTRODUCTION: Pelvic arteriovenous malformations (AVMs) are rare vascular anomalies that may cause marked venous engorgement and increase the risk of massive hemorrhage during pelvic surgery. When rectal cancer coexists with a pelvic AVM, achieving oncological radicality while maintaining surgical safety becomes particularly challenging. CASE PRESENTATION: A patient with rectal cancer complicated by a pelvic AVM was referred for surgical treatment. Preoperative imaging demonstrated a pelvic AVM supplied by branches of the internal iliac artery with venous drainage into the rectal venous plexus. Selective preoperative coil embolization was performed to treat the AVM while rectal arterial perfusion was preserved. Robotic-assisted total mesorectal excision (TME) was subsequently undertaken. Despite residual presacral venous dilatation related to chronic hemodynamic changes, robotic-assisted TME was completed without hemorrhagic complications. Intraoperative indocyanine green fluorescence angiography confirmed adequate perfusion of both the proximal colon and the distal rectal stump, allowing safe primary anastomosis without a diverting stoma. The postoperative course was uneventful. CONCLUSIONS: Rectal cancer associated with a pelvic AVM presents unique surgical challenges due to altered pelvic vascular anatomy. This case suggests that careful preoperative planning, selective embolization, and appropriate integration of advanced surgical techniques may facilitate safe radical resection in similarly complex pelvic conditions.