A case of arteriovenous malformation in the inferior mesenteric artery region resected surgically under intraoperative indocyanine green fluorescence imaging.

INTRODUCTION AND IMPORTANCE: An arteriovenous malformation (AVM) is defined as a vascular malformation with a short, non-capillary communication between the arteries and veins. Most gastrointestinal AVMs are solitary, occurring predominantly in the stomach, small intestine and right colon, and rarely in the inferior mesenteric artery (IMA) region. CASE PRESENTATION: A 70-year-old man was first diagnosed with ischemic enteritis two years earlier, and was hospitalized several times with the same diagnosis. He visited our hospital because of left lower abdominal pain and melena. Colonoscopy showed findings suggestive of ischemic enteritis, and contrast-enhanced computed tomography (CT) and IMA angiography showed hyperplasia and dilation of blood vessels from the sigmoid-descending colon junction to the upper rectum. We performed conventional laparoscopic low anterior resection using intraoperative intravenous injection of indocyanine green (ICG). The final diagnosis was arteriovenous malformation in the IMA region. The patient had an uneventful postoperative course and was discharged on the 13th day after the operation. CLINICAL DISCUSSION: Cases of AVM in the IMA region are relatively rare. This is the first reported case of AVM in the IMA region that was resected under intraoperative ICG fluorescence imaging (FI), which provided useful information on the extent of intestinal resection and mesenteric dissection required, and confirmed the adequacy of intestinal blood flow during and after mesenteric dissection and anastomosis. CONCLUSION: It is advisable to use ICG FI intraoperatively during resection of AVMs in the IMA region, as with colorectal cancer surgery.